(MTE Ordinance No. 836, of May 27, 2024)
Summary:
22.1 Objective
22.2 Scope
22.3 Organization’s Responsibilities
22.4 Occupational Risk Management (ORM)
22.5 Workers’ Rights and Duties
22.6 Organization of Workplaces and Activities
22.7 Circulation and Transportation of People and Materials
22.8 Continuous Conveyors
22.9 Work Surfaces, Mobile Platforms, and Walkways
22.10 Stairs
22.11 Hoisting Equipment
22.12 Machinery, Equipment, and Tools
22.13 Stability of Massifs
22.14 Underground Openings: Development, Treatment, and Support and Sign Systems
22.15 Protection against Mineral Dust
22.16 Communication Systems
22.17 Signs
22.18 Electrical Installations
22.19 Operations with Explosives and Accessories
22.20 Activities with Floating Dredges
22.21 Hydraulic Disassembly
22.22 Ventilation in Underground Activities
22.23 Beneficiation
22.24 Waste, Tailings, and Product Disposal
22.25 Lighting
22.26 Prevention against Fires and Accidental Explosions
22.27 Prevention of Explosive Dust Explosions in Underground Coal Mines
22.28 Flood Protection
22.29 Radioactive Equipment
22.30 Emergency Response Plan (ERP)
22.31 Emergency Exits and Routes in Underground Mines
22.32 Suspension and Resumption of Activities in Mines
22.33 Internal Committee for Accident and Harassment Prevention in Mining (CIPAMIN)
22.34 Sanitary and Comfort Conditions in Workplaces
22.35 General Provisions
Glossary
Annex I – Steel Cables, Chains, and Accessories
Annex II – Training and Qualification
Annex III – Minimum Requirements for the Use of Fixed Boom Hoisting Equipment
Annex IV – Tables
22.1 Objective
22.1.1 This Regulatory Standard aims to establish the precepts to be observed in organizations to ensure that the planning and development of mining activities are compatible with the ongoing pursuit of workers’ safety and health.
22.2 Scope
22.2.1 This standard applies to organizations that carry out activities related to:
a) underground mining, including mining operations covered by the Small-Scale Mining Permit (PLG);
b) open-pit mining, including mining operations covered by the PLG;
c) mineral processing facilities located within mining areas and PLG-covered areas; and
d) mineral research.
22.3 Responsibilities of the Organization
22.3.1 It is the responsibility of the organization to:
a) ensure strict compliance with this Standard;
b) designate the technical managers for each sector; and
c) halt any activity that exposes workers to conditions of grave and imminent risk to their health and safety.
22.3.2 All mines and other activities referred to in item 22.2.1 of this NR must be under the technical supervision of a legally qualified professional.
22.3.2.1 The organization must keep records, either physical or electronic, of the technical supervision activities as outlined in item 22.3.2 of this NR, documenting occurrences, observations, proposed interventions, whether implemented or not, that may affect mine safety.
22.4 Occupational Risk Management
22.4.1 The organization is responsible for implementing Occupational Risk Management in its activities, preferably per establishment, as defined in NR-1 (General Provisions and Occupational Risk Management).
22.4.1.1 The Occupational Risk Management Program (PGR) should preferably be developed by a multidisciplinary team and implemented under the organization’s responsibility.
22.4.1.2 In addition to the requirements in NR-1, the PGR must address the hazards and their respective preventive measures as outlined in this standard.
22.4.1.2.1 The hazard identification and occupational risk assessment process outlined in item 1.5.4 of NR-1 must consider, where applicable, the following aspects:
a) explosive atmospheres;
b) oxygen deficiencies;
c) mechanical ventilation;
d) respiratory protection, adopting the Respiratory Protection Program (PPR) of the Jorge Duprat Figueiredo Foundation for Occupational Safety and Health (FUNDACENTRO) and its amendments or another equivalent program;
e) hearing protection, adopting the Guidelines and Minimum Parameters for the Development and Management of the Hearing Conservation Program (PCA), 2018, by FUNDACENTRO and its amendments or another equivalent program;
f) underwater work;
g) stability of natural and modified or constructed masses by the organization; and
h) modifications and introductions of new technologies.
22.4.2 When service provision occurs in the activities specified within the scope of this NR in the premises of the contracting party or in a location previously agreed upon in the contract, in addition to the provisions of item 1.5.8 of NR-1, the following must be observed:
a) the contracting and contracted parties must execute integrated actions to apply the preventive measures outlined in this NR, aiming to protect all workers exposed to occupational risks;
b) the PGR of the contracting organization must include the preventive measures for the contracted organizations or reference the programs of the contracted parties;
c) when the activities carried out by the contracting and contracted parties are performed simultaneously, the contracting party must coordinate the implementation of the preventive measures outlined in this NR;
d) the contracting party must provide the contracted party with information on the hazards and occupational risks under its management that are present in the areas where the contracted party will carry out its activities and, where applicable, the preventive measures to be adopted; and
e) the contracted organizations must provide the contracting party with an inventory of occupational risks specific to their activities carried out in the areas where the service will be provided.
22.4.3 In addition to the provisions of item 1.5.7 of NR-1, the organization must:
a) include in the PGR the safety and health procedures at work, as outlined in this NR; and
b) maintain in the establishment:
I – the inventory of Risks prepared by the contracted parties, where applicable;
II – traffic plan; and
III – load plans.
22.5 Rights and Duties of Workers
22.5.1 In addition to the provisions of NR-1, workers have the right to stop their tasks whenever they find evidence of serious and imminent risks to their safety and health or that of others, immediately reporting the situation to their superior, who will take the appropriate measures.
22.5.2 Workers are required to immediately report to their superior any situation they consider to pose a risk to their safety and health or that of others.
22.6 Organization of Workplaces and Activities
22.6.1 The organization shall take the necessary measures to ensure that workplaces are designed, constructed, equipped, used, and maintained so that workers can perform their assigned tasks, eliminating or minimizing risks to their safety and health as much as practicable and feasible.
22.6.2 Mining areas with operational activities must have marked access routes and roads, and identified entrances, displaying the organization’s name, the mining process number with the National Mining Agency (ANM), the geographical coordinates of its location, the legally responsible technical manager for the project, as well as the requirements defined in ANM regulations.
22.6.3 In the following activities, when not performed remotely, teams of at least two workers must be designated:
a) Underground, in activities such as:
I – collapse of loose rock and unstable blocks;
II – containment of disarticulated rock masses;
III – rock mass drilling;
IV – resumption of activities in dead-end areas longer than 10 meters; and
V – loading explosives, detonation, and removal of failed blasts;
b) Open-pit, in activities such as loading explosives, detonation, and removal of failed blasts.
22.6.3.1 When the activities described in sub-items “I” and “III” of item 22.6.3 are mechanized, a risk analysis may indicate the involvement of only one worker.
22.6.3.2 The organization must establish safety procedures for the supervision and control of other workplaces where work can be carried out alone.
22.6.4 Organizations involved in handling, manipulation, storage, and transport of flammable and/or combustible liquids underground must include in the PGR, in addition to the requirements of this standard:
a) the inventory and characteristics of the flammable and/or combustible liquids;
b) the specific hazards related to the locations and activities involving flammable and/or combustible liquids;
c) the procedures and plans for accident prevention involving flammable and/or combustible liquids; and
d) the measures for action in emergency situations.
22.6.4.1 The organization must have at least two workers trained in the basic course provided in Annex I of NR-20 (Health and Safety at Work with Flammables and Combustibles), per shift, who provide services underground and are directly involved with flammable and/or combustible liquids.
22.6.5 The collective fall protection system consisting of guardrails and toe boards, as specified in this NR, must have the following characteristics:
a) be safely and securely dimensioned, constructed, and fixed to withstand the expected loads;
b) be made of weather- and corrosion-resistant materials;
c) have a top rail installed between 1.1 meters and 1.2 meters in height from the floor along the entire length;
d) the top rail should not have a flat surface to prevent the placement of objects; and
e) have a toe board at least 20 cm high and an intermediate rail at 70 cm from the floor, located between the toe board and the top rail.
22.6.6 Galleries and workplaces must be adequately drained when applicable.
22.7 Circulation and Transport of People and Materials
22.7.1 Every mine must have a traffic plan establishing rules for movement preference, minimum distances between machines, equipment, and vehicles compatible with safety, and allowed speeds according to the road conditions.
22.7.1.1 In open-pit mines and external areas of underground mines, the traffic plan must include:
a) a layout identifying the circulation routes with their widths, updated as needed based on mine operations;
b) the location of signs;
c) the location of pull-off areas and intersections, when present.
22.7.2 Circulation routes must be signposted, unobstructed, protected against material falling, maintained in good safety and traffic conditions, and preferably lit or with other measures ensuring worker safety in low visibility conditions.
22.7.2.1 At intersections and main branch locations, directions and mine exits, including emergency exits, must be indicated.
22.7.2.2 The signs of the mine’s circulation routes must be kept updated.
22.7.3 When the total walking distance for a worker to and from their activity location exceeds 1,000 meters, the mine must provide a transportation system for this movement.
22.7.4 Ore treatment facilities over 12 meters high must have a mechanized vertical transportation system for people and materials to access work locations, and it is prohibited to install elevators with a single cable or those adapted with more than one cable that do not meet current national technical standards. (5 years implementation period for ore treatment facilities already in operation or technical proof in the event of unfeasibility of implementation according to Art. 3 of MTE Ordinance No. 225, of February 26, 2024)
22.7.5 Unpaved vehicle circulation routes must be kept moist or other means used to minimize dust generation.
22.7.6 Traffic routes in open-pit mines must comply with the following requirements:
a) the external limits of the benches used as roads must be marked and visibly signposted during the day and night, with light signals in adverse visibility conditions;
b) the minimum width of traffic routes must be twice the width of the largest vehicle used for single-lane roads and three times for double-lane roads;
c) on the sides of the benches or roads where there is a risk of vehicle falls, berms with a minimum height corresponding to half the diameter of the largest tire of vehicles passing through must be constructed;
d) escape areas must be built along the routes, with their locations defined in the traffic plan.
22.7.6.1 When the mine plan and the nature of the activities carried out or the size of the mine do not allow compliance with item 22.7.6(b), the width of the traffic routes may be at least one and a half times the width of the largest vehicle used, and in this case, there must be interspersed bays for vehicle parking and additional procedures and signs to ensure safe traffic, as provided in the traffic plan.
22.7.7 Small vehicles operating in open-pit mining areas must keep their headlights on all day to facilitate visibility and have signaling through flashing lights and a flag on a telescopic antenna or another device that allows their visualization by operators of other equipment and vehicles.
22.7.8 In underground galleries or ramps with two-way traffic, there must be designated areas for deviations at regular intervals or signaling devices indicating priority flow, to avoid simultaneous traffic in opposite directions.
22.7.9 When there is a single route for personnel circulation and material transport or vehicle traffic underground, the gallery must have a minimum width of 1.5 meters beyond the width of the largest vehicle traveling through it, with established circulation rules.
22.7.9.1 When the mine plan and the nature of the activities do not allow the existence of the safety distance provided in item 22.7.9, openings must be built in the gallery or ramp walls, at least 60 cm deep, 2 meters high, and 1.5 meters long, properly signposted and unobstructed every 50 meters, for personnel shelter.
22.7.10 When winches are used to transport material on inclined planes without specific and isolated pedestrian barriers, they must remain stopped while personnel circulate.
22.7.11 If there is an irregularity that poses a risk to transportation by cage or inclined plane, the winch operation must be immediately prohibited, and appropriate measures promptly taken to restore transportation safety.
22.7.12 Material transport by means of mine carts is prohibited. (5 years implementation period for mines using railcars according to Art. 3 of MTE Ordinance No. 225, of February 26, 2024)
22.7.13 The operation of transportation equipment for people and materials is only permitted for trained, authorized, and identified workers by the organization.
22.7.14 Transportation equipment must have locking devices that prevent unauthorized operation.
22.7.15 The capacity and maximum operating speed of transportation equipment must be displayed on a visible plate.
22.7.16 Rubber-tired transportation equipment must have:
a) headlights;
b) reverse light and sound signal connected to the gear shift system;
c) horn;
d) signal indicating direction change; and
e) rearview mirrors or a camera system replacing them.
22.7.16.1 The devices mentioned in item 22.7.16 must be kept in good condition and working order.
22.7.17 Vehicles used for transporting workers in all mine areas must be designed and built for this purpose.
22.7.17.1 In underground mines, worker transportation can be done using adapted vehicles that meet the following requirements:
a) safe traffic conditions;
b) foam seat with backrest;
c) seat belt;
d) protection against weather conditions and accidental contact with the gallery roof; and
e) ladder for boarding and disembarking, when necessary.
22.7.17.1.1 In situations where using a seat belt may pose additional hazards to the worker, its use may be waived, provided safety procedures for these situations are observed.
22.7.18 The joint transportation of people and materials such as tools, equipment, supplies, and raw materials is only permitted in quantities compatible with safety and when securely stored in an appropriate, closed, and fixed compartment to prevent injury to workers.
22.7.19 Vertical transportation equipment for materials and people must be designed by a legally qualified professional and meet current national technical standards or applicable international technical standards.
22.7.20 The vertical transportation of people is only permitted in cabins or cages with the following characteristics:
a) a minimum height of 2 meters;
b) gates on each level with an interlocking device monitored by a safety interface to prevent unauthorized access to the shaft;
c) doors with an interlocking device monitored by a safety interface to prevent movement with the doors open;
d) a sturdy roof with a handrail and emergency exit;
e) lateral protection to prevent accidental access to the outside area;
f) lighting;
g) conveniently protected access;
h) a distance of less than 15 cm between the access platform and the cage;
i) a communication system with the winch operator at boarding and disembarking points;
j) a sound and light signaling system or radio or telephone communication allowing communication along the entire shaft for maintenance and emergency purposes; and
k) devices that interrupt the winch’s electric current when the cabin or cage, when ascending or descending, exceeds the allowed speed and positioning limits.
22.7.20.1 The braking system of the vertical transportation equipment must be activated when:
a) there is a stop command;
b) the transportation system is deactivated;
c) the protective devices are activated;
d) there is a power interruption;
e) the speed limit is exceeded; and
f) the maximum load limit is exceeded.
22.7.20.1.1 The braking system can only release the vertical transportation equipment when the engines are running.
22.7.21 Transportation equipment for people on ramps or inclined planes on rails must meet the following minimum requirements:
a) have seats equal to the maximum user capacity;
b) have front and top protection to prevent accidental contact with the roof;
c) embark or disembark people only in appropriate places; and
d) winches must have at least two steel cables, each individually capable of supporting the loads in case one breaks.
22.7.22 The transportation of people during the shaft opening and equipping phase must meet the following minimum requirements:
a) the shaft must have a protective cover with a hinged opening to prevent material or people from falling and must remain closed while people are in the shaft;
b) the shaft collar must be concreted;
c) the transport bucket must be constructed of quality material, resistant to the transported load, and with a minimum side height of 1.2 meters;
d) a maximum speed of 1.2 meters per second, which must be reduced during the approach to the bottom of the shaft;
e) have specific sound signaling, as per chapter 22.16 of this NR; and
f) not transport people and materials together.
22.8 Continuous Conveyors
22.8.1 The design, installation, assembly, operation, and maintenance of continuous conveyors must comply with the requirements of this NR, NR-12 (Machinery and Equipment Safety), and the technical specifications of current national or applicable international technical standards.
22.8.1.1 Continuous conveyors already in use and built before January 2011 must have control measures to mitigate the hazards identified in the PGR.
22.8.2 The design and construction of continuous conveyors must consider the system’s tensioning to ensure adequate tension for safe operation, as specified in the design.
22.8.3 Emergency stop devices along the entire length of continuous conveyors, activated by cable, must operate under tension, automatically stopping the equipment’s hazardous functions in case of cable breakage or slackening.
22.8.4 Continuous conveyors must have devices that stop their operation when safety limits are reached, as specified in the design, covering at least the following conditions:
a) belt breakage;
b) abnormal belt slippage relative to the drums;
c) abnormal belt misalignment; and d) overload.
22.8.5 In coal mines, conveyor belts must be made of self-extinguishing material.
22.8.5.1 In coal mines, all necessary measures must be taken to prevent the accumulation of coal dust along the moving parts of the conveyor belt systems where friction heating could occur.
22.8.6 The start-up of continuous conveyors is only permitted twenty seconds after an audible signal with automatic activation or another automatically activated communication system indicating the start of movement.
22.8.7 The floors of continuous conveyor walkways must be non-slip, durable, and maintained in proper working condition.
22.8.8 Conveyors that, due to the nature of the operation, cannot support the structure of walkways must have this condition certified by a legally qualified professional and must have an alternative safety system and procedure for inspection and maintenance.
22.8.9 Elevated continuous conveyors must be equipped with protective devices where there is a risk of falling or uncontrolled material ejection.
22.8.10 Cleaning and maintenance work on continuous conveyors must be carried out according to item 12.11.3 of NR-12, except when cleaning is done by water jet or other systems, which must then have a mechanism preventing accidental worker contact with moving parts.
22.8.11 Material transportation by cableway must comply with the requirements of NR-12.
22.8.12 The endless cable of the material transport system by cableway can only operate under the following conditions:
a) having an anti-reverse system that prevents continued movement in case of shutdown;
b) protecting the moving parts of the drive and return stations;
c) being installed in a way that eliminates abrupt and uncontrolled movements; and
d) starting only twenty seconds after an audible automatic signal or another automatic communication system indicating its activation.
22.9 Work Surfaces, Mobile Platforms, and Walkways
22.9.1 Workstations must have mobile platforms whenever the height of the work fronts exceeds 2 meters or the floor configuration does not provide the necessary safety.
22.9.1.1 Mobile platforms must have a non-slip floor at least 1 meter wide, with a collective fall protection system, with the dimensions specified in item 22.6.5 of this NR.
22.9.1.2 It is prohibited to use machines and equipment as work platforms if they have not been designed and built for this purpose.
22.9.1.3 Machines and equipment adapted for use as work platforms must be guaranteed to be safe to use and operated by a legally qualified professional.
22.9.2 Suspended walkways and their access points must be stable and in proper working condition and have a collective fall protection system with the dimensions specified in item 22.6.5 of this NR.
22.9.2.1 The floors of the walkways must be non-slip, durable, and maintained in safe condition.
22.9.2.2 Work walkways must be at least 80 cm wide, and those intended for occasional use may be 60 cm wide.
22.9.2.3 Work walkways built and in operation, which were not designed and built according to the requirements of item 22.9.2 and sub-items 22.9.2.1 and 22.9.2.2 of this NR, must have appropriate safety procedures for operation.
22.9.3 Work on waste and ore piles and in gallery clearance must be carried out according to safety procedures developed by the organization.
22.9.4 For work carried out on inclined surfaces with a fall risk of more than 2 meters, the provisions of NR-35 (Working at Height) must be followed.
22.9.5 For crossing pits, chimneys, or floor openings, walkways equipped with a collective fall protection system must be installed, with the dimensions specified in item 22.6.5 of this NR.
22.10 Stairs
22.10.1 When the access to workplaces involves stairs, they must have the following minimum characteristics:
a) Be dimensioned, constructed, and securely fixed;
b) Be rigid and capable of withstanding the required loads, thereby minimizing the risk of falls;
c) Be free of loose or broken elements;
d) Be made of or coated with weather-resistant and corrosion-resistant materials if exposed to external or corrosive environments; and
e) Have uniform steps and flights.
22.10.1.1 When the means of access to workplaces have an inclination greater than 20° (twenty degrees) and less than 50° (fifty degrees) with the horizontal, a securely fixed stair system must be installed with the following characteristics:
a) Have risers between steps with a height between 18 cm (eighteen centimeters) and 20 cm (twenty centimeters);
b) Have a maximum vertical distance between planes or flights of 3.6 m (three meters and sixty centimeters);
c) Have a collective fall protection system with dimensions as specified in item 22.6.5 of this NR; and
d) Have an anti-slip floor material.
22.10.1.2 When the means of access to workplaces have an inclination between 50° (fifty degrees) and 70° (seventy degrees) with the horizontal, a stair system must be installed with the following characteristics:
a) Have a distance between steps of 25 cm (twenty-five centimeters) to 30 cm (thirty centimeters);
b) Have a minimum spacing of 10 cm (ten centimeters) between the step and the wall or other obstruction behind the stair, providing secure foot support;
c) Have a rest platform with a minimum width of 60 cm (sixty centimeters) and a length of 1.2 m (one meter and twenty centimeters) at intervals of no more than 7 m (seven meters), with sufficient opening to allow worker passage; and
d) Continuation of the ladder’s uprights exceeding the rest platform or the upper floor by at least 1 m (one meter).
22.10.1.3 When the means of access to workplaces have an inclination greater than 70° (seventy degrees) with the horizontal, a stair system must be installed with the following characteristics:
a) Protection cages, if the height exceeds 3.5 m (three meters and fifty centimeters), installed from 2 m (two meters) from the floor, extending beyond the rest platform or the upper floor by at least 1 m (one meter), with a diameter of 65 cm (sixty-five centimeters) to 80 cm (eighty centimeters), having vertical bars with a maximum spacing of 30 cm (thirty centimeters) between them and a maximum distance of 1.5 m (one meter and fifty centimeters) between arches or spans between arches of no more than 30 cm (thirty centimeters), equipped with a vertical support bar for the arches;
b) Continuation of the ladder’s uprights exceeding the rest platform or the upper floor by at least 1 m (one meter);
c) A maximum total height of 10 m (ten meters), if it is a single flight;
d) A maximum height of 7 m (seven meters) between two rest platforms if it is a multi-flight system, built in consecutive flights with parallel axes, spaced at least 70 cm (seventy centimeters);
e) Have a distance between steps of 25 cm (twenty-five centimeters) to 30 cm (thirty centimeters);
f) A spacing between the lower floor and the first step of no more than 40 cm (forty centimeters);
g) A minimum spacing of 10 cm (ten centimeters) between the step and the wall or other obstruction behind the stair, providing secure foot support; and
h) Steps with surfaces that prevent slipping.
22.10.2 The use of individual fall protection systems, in accordance with NR-35, is mandatory on fixed vertical ladders with a height greater than 2 m (two meters).
22.10.3 Wooden stairs must have the following minimum characteristics:
a) The wood must be of good quality, free from knots or cracks that compromise its strength;
b) Not be painted or treated in a way that hides imperfections;
c) Have a distance between steps of 25 cm (twenty-five centimeters) to 30 cm (thirty centimeters);
d) Have a spacing of at least 10 cm (ten centimeters) between the steps and the wall or other obstruction behind the stair, providing secure foot support; and
e) Extend at least 1 m (one meter) above the floor or opening, unless there is a sturdy handrail at the top of the stair.
22.10.4 In the case of using metal stairs, additional safety measures must be adopted when they are near electrical installations.
22.10.5 The use of chain ladders is only permitted during the opening phases of shafts in underground mines.
22.10.6 Access to machines and equipment via stairs must comply with the requirements of NR-12, and the provisions of chapter 22.10 of this NR do not apply.
22.11 Lifting Equipment
22.11.1 Lifting equipment must have:
a) Indication of the maximum allowable load and the maximum operating speed, along with devices that ensure it stops if these limits are exceeded;
b) Speed indicator and limiter for machines with power exceeding forty kilowatts;
c) In underground environments, an independent depth indicator for the drum;
d) A safety brake to prevent rollback; and
e) An emergency brake when used for transporting people.
22.11.1.1 Lifting equipment must be used in accordance with the manufacturer’s recommendations and the load plan.
22.11.1.1.1 The load plan must be prepared by a legally qualified professional.
22.11.2 The means of transporting and removing materials underground, powered by a winch, must meet the following minimum requirements:
a) A braking system designed to sustain up to one and a half times the maximum working load, regardless of its position;
b) Gates at each level with a safety interface-monitored interlocking device to prevent unauthorized access to the shaft; and
c) Devices that cut off the winch’s electrical power when the equipment exceeds the permitted speed and positioning limits during ascent or descent.
22.11.2.1 The vertical material transport equipment’s braking system must be activated when:
a) A stop command is given;
b) The transport system is deactivated;
c) The protection devices are activated;
d) There is a power interruption;
e) The speed limit is exceeded; and
f) The maximum allowable load is exceeded.
22.11.2.2 The braking system can only release the vertical material transport equipment when the motors are running.
22.11.3 Lifting equipment must be assembled according to the manufacturer’s recommendations and applicable technical standards.
22.11.4 When using fixed boom lifting equipment, the minimum requirements outlined in Annex III of this NR must be followed.
22.12 Machines, Equipment, and Tools
22.12.1 The provisions of this standard and NR-12 apply to machines, equipment, and tools as appropriate.
22.12.2 Machines, equipment, and tools used in environments with a potential for explosive atmospheres must be explosion-proof.
22.12.3 Machines, equipment, and tools generating vibrations must be maintained to ensure their integrity and lubrication of their moving components.
22.12.4 Electrical machines, equipment, and tools must be connected to the power supply through a plug and socket assembly, in compliance with applicable national technical standards.
22.12.5 The hoses and connections supplying stationary pneumatic machines and equipment must have the following characteristics:
a) Remain protected, firmly attached to the outlet and inlet tubes, and preferably away from circulation paths; and
b) Be equipped with an auxiliary device that ensures the hose is contained, preventing whipping in case of accidental detachment.
22.12.6 The hydraulic cylinders of machines and equipment must be equipped with safety systems to prevent falls in case of pressure loss in the hydraulic system.
22.12.7 Safety systems must be mounted directly on the cylinder body, or if not possible, rigid tubing, welded or flanged, must be used between the cylinder and the valve.
22.12.8 Hydraulic jacks used in mass shoring activities must be associated with redundancy devices or other devices that ensure safety in case of hydraulic jack failure.
22.12.9 Containers holding compressed gases must be stored in well-ventilated areas and protected against falls, heat, and accidental impacts, as well as complying with applicable national technical standards and manufacturer recommendations.
22.12.10 Self-propelled machines and equipment whose unauthorized activation could endanger the health or physical integrity of any person must have an ignition key to lock their activation devices.
22.12.11 Self-propelled machines with a tare weight exceeding 4,500 kg (four thousand five hundred kilograms) must have an air-conditioned cabin and provide protection against falling and projecting objects, as well as solar radiation and weather conditions. (3 years implementation period for new self-propelled machines according to Art. 3 of MTE Ordinance No. 225, of February 26, 2024)
22.12.11.1 Self-propelled machines with a tare weight equal to or less than 4,500 kg (four thousand five hundred kilograms) must have a workstation protected against falling and projecting objects, as well as solar radiation and weather conditions. (5 years implementation period for used self-propelled machines according to Art. 3 of MTE Ordinance No. 225, of February 26, 2024)
22.12.12 Self-propelled machines and equipment must have at least one simple, non-monitored mechanical interlock device to protect the engine compartment.
22.12.13 The installation of safety systems on self-propelled machines and equipment must be carried out by a legally qualified professional or a qualified or trained professional, duly authorized by the organization.
22.12.14 Self-propelled machines and equipment must have securely fixed accesses to all their operation, refueling, raw material insertion and finished product removal, preparation, maintenance, and constant intervention points.
22.12.15 Locations or workstations above floor level, where workers have access for operations or any other routine interventions on self-propelled machines and equipment, such as refueling, preparation, adjustment, inspection, cleaning, and maintenance, must have stable and secure work platforms.
22.12.15.1 In the technical impossibility of applying the provisions of item 22.12.15 of this NR, the use of Mobile Elevated Work Platforms (MEWPs) may be adopted.
22.12.16 It is prohibited to maintain the support of self-propelled machines and equipment solely by hydraulic cylinders during maintenance.
22.12.17 The refueling of self-propelled machines and equipment with an internal combustion engine must be carried out by trained workers, in an appropriate location, using techniques and equipment that ensure operational safety.
22.12.18 The activation of large self-propelled machines and equipment must be preceded by the emission of an automatic sound signal.
22.12.19 Workers must be trained and instructed in the use of tools, following the safety recommendations of this standard and, where applicable, the manufacturer’s manual.
22.12.20 When using tools, loose clothing and adornments that may endanger the worker’s safety must be avoided.
22.12.21 Tools must be visually inspected by the user before use.
22.12.22 Tools must be suitable for their intended use, and the use of defective, damaged, or improvised tools is prohibited.
22.12.23 The organization must only use electrical tools that have a starting device installed to avoid the possibility of accidental operation.
22.12.24 The starting devices of electrical tools must be continuous action devices, and the use of a lock in the on position is prohibited.
22.12.25 The power supply system of electrical tools must be handled in a way that does not twist, break, or abrade, nor obstruct the movement of workers, machines, and equipment.
22.12.26 Electrical tools may only be used with their protection devices properly installed.
22.12.27 Electrical tools used for cutting must be equipped with a disc specific to the type of material to be cut.
22.12.28 The use of portable electrical tools without double insulation is prohibited.
22.12.29 The organization must only use pneumatic tools that have a starting device installed to avoid the possibility of accidental operation.
22.12.30 The starting devices of pneumatic tools must be continuous action devices, and the use of a lock in the on position is prohibited.
22.12.31 The air valve of the pneumatic tool must automatically close when the operator’s hand pressure on the starting devices ceases.
22.12.32 The hoses and connections for the supply of pneumatic tools must withstand service pressures and remain firmly attached to the outlet tubes and away from circulation paths.
22.12.33 Pneumatic tools must be disconnected when not in use, with prior shutdown of the air supply to the hoses and pressure relief.
22.12.34 The following is prohibited when using pneumatic tools:
a) Using them to clean clothes; and
b) Exceeding the maximum air pressure.
22.12.35 During the initial drilling operations in walls and ceilings with pneumatic hammers, an appropriate device must be used to secure the shaft, and the exclusive use of hands is prohibited.
22.12.36 Powder-actuated fastening tools must have a safety system to prevent accidental firing.
22.12.37 The operator of a powder-actuated fastening tool must be qualified and authorized.
22.12.38 The use of powder-actuated fastening tools is prohibited:
a) In environments containing flammable or explosive substances; and
b) In the presence of people, including helpers, within the projectile’s range of action.
22.12.39 Powder-actuated fastening tools must be unloaded (without the pin and fixing pin) whenever they are not in use and stored in a restricted-access location.
22.12.39.1 Before fixing pins with the tool, the most suitable type of pin and fixing pin must be checked.
22.12.40 The organization must provide workers with the necessary hand tools for free.
22.12.41 Workers are obliged to take care when using hand tools and to return them to the organization whenever requested.
22.12.42 Hand tools must not be left on walkways, stairs, scaffolds, and other work or circulation surfaces and must be stored in appropriate locations when not in use.
22.12.43 Hand tools used in electrical installations must be insulated according to the voltage involved, in compliance with NR-10 (Safety in Electrical Installations and Services).
22.12.44 Hand tools must be transported in proper containers.
22.12.45 Scaling rods must be ergonomically compatible with the work to be performed, considering operational safety, having sufficient length and strength and the smallest possible weight to avoid excessive muscle strain.
22.13 Stability of Rock Masses
22.13.1 The maps and plans of topographic surveys for underground and open-pit mining must be made available, upon request, to regulatory authorities and worker representatives.
22.13.2 The organization must adopt technical procedures to control the stability of rock masses, observing engineering criteria, including actions to:
a) Monitor the movement of strata;
b) Properly treat the roof and walls of work and personnel circulation areas;
c) Monitor and control the benches and slopes of open-pit mines;
d) Verify the impact on the stability of previously mined areas; and
e) Check for factors that could destabilize rock masses, especially water, gases, altered rocks, faults, and fractures.
22.13.2.1 Mining methods that involve controlled caving of the rock mass or pillar recovery must be accompanied by safety measures that allow continuous monitoring of the extraction process by qualified personnel under the responsibility of a legally qualified professional.
22.13.3 When potential instability situations in the rock mass are detected through evaluations that consider the geotechnical and geomechanical conditions of the site, activities must be immediately halted, workers must be removed from the risk area, necessary corrective measures must be taken by trained workers under the supervision of a legally qualified professional.
22.13.3.1 The following occurrences are considered indicative of potential instability in the rock mass:
a) In open-pit mines:
I. Fractures or blocks detached from the main body on the faces of the pit benches and the opening of cracks at the top of the bench;
II. Opening of fractures in rocks with the possible emergence of water;
III. Features of surface subsidence;
IV. Structures on negative slopes; and
V. Water percolation through fracture planes or mechanical breaks;
b) In underground mines:
I. Mechanical breaks with blocks detached from the roof or walls;
II. Mechanical breaks in the roof, host rocks, or support pillars;
III. Emergence of an abnormal volume of water during excavation, drilling, or after blasting; and
IV. Significant deformation in support structures.
22.13.3.2 If the situations described in subitem 22.13.3.1 of this NR occur without proper monitoring, as provided in item 22.13.2 of this NR, activities must be immediately halted, without prejudice to the necessary corrective measures.
22.13.3.2.1 The resumption of operational activities can only occur after corrective measures have been taken and formal clearance of the area by the responsible technical supervision.
22.13.4 The deposition of any material near the crest of benches and the parking of machinery must observe a minimum safety distance, defined based on the stability and height of the bench and must be included in the PGR.
22.13.5 It is mandatory to stabilize or remove material at risk of falling from the upper bench crest.
22.14 Underground Openings: Development, Treatment, and Support and Sign Systems
22.14.1 Underground openings must be designed, executed, and maintained during their useful life, observing the provisions of this standard, ANM standards, and applicable national and international standards.
22.14.1.1 All underground openings must be evaluated and treated according to their hydrogeomechanical characteristics and the purposes for which they are intended, under the responsibility of a legally qualified professional.
22.14.1.2 For mines requiring treatments, the respective plans must be available, updated, with technical descriptions and justifications of the systems used.
22.14.1.3 Treatment services and their recovery must be performed only by trained workers.
22.14.1.4 In the development of galleries, shafts, inclined planes, ramps, and main axes, locations where there is fixed work, mining in already mined, weathered areas, or along zones with geological disturbances, appropriate safety treatment techniques must be used.
22.14.2 At the collar of shafts and mine entrances, control measures must exist to prevent the entry of water in quantities that compromise their stability or cause collapses.
22.14.3 Galleries must be designed and constructed to ensure the safety of machine and equipment operators passing through them, ensuring adequate traffic conditions and preventing accidental contact with the roof and walls, and must be part of the mine traffic plan.
22.14.4 In mining influence areas, the development of other underground works that could compromise their stability and worker safety is not allowed.
22.14.5 Openings that may pose a risk of material or person falls must be signaled and have a collective fall protection system, with the dimensions provided in item 22.6.5 of this NR.
22.14.6 Underground openings and work fronts must be periodically inspected to identify unstable blocks and rock hazards.
22.14.6.1 Inspections must be conducted with special care when resuming mining fronts after blasting.
22.14.7 If unstable blocks are found, their influence area must be physically isolated until they are treated or removed.
22.14.7.1 If rock hazards are found, they must be immediately removed.
22.14.7.2 The removal of rock hazards or unstable blocks must preferably be done using mechanized equipment designed for this purpose, and if technically unfeasible, using appropriate devices for the activity, which must be available at all work fronts and carried out by trained workers, following safety procedures developed by the organization.
22.14.8 The bottom of elevator and cage shafts must be lowered beyond the last level, adequately sized, equipped with drainage systems, and cleaned periodically to maintain a safe depth.
22.14.9 The deposits of dismantled materials near access levels to shafts and inclined planes must be adequately protected against sliding or placed at a distance greater than 10 m (ten meters) from the opening.
22.14.10 Access roads, transit routes, and other openings with inclinations greater than thirty-five degrees must be protected to prevent sliding and falls of objects and people.
22.14.11 All main galleries must be visibly identified and signaled.
22.14.12 Underground areas that have already been mined or deactivated must remain signaled and interdicted, with access allowed only to authorized personnel.
22.14.13 The organization must systematically and periodically inspect all active mine treatment as defined in its procedures.
22.14.13.1 If the treatment is compromised, additional measures must be taken to ensure worker safety.
22.14.13.2 The recovery services of mine treatment must be under the responsibility of a legally qualified professional.
22.14.14 All shoring materials must be protected against moisture and replaced in case of rot, corrosion, or other types of deterioration.
22.15 Protection Against Mineral Dust
22.15.1 In locations where dust is generated on the surface or underground, the organization must periodically monitor workers’ exposure through Similar Exposure Groups and the control measures adopted, recording the data in compliance with, at a minimum, Table III of Annex IV of this NR.
22.15.2 A Similar Exposure Group corresponds to a group of workers who experience similar exposure, such that the result provided by the exposure assessment of any worker in the group is representative of the exposure of the rest of the workers in the same group.
22.15.3 When the tolerance limits for exposure to mineral dust are exceeded, technical and administrative measures must be adopted to eliminate, reduce, or neutralize its effects on workers’ health, considering the action levels according to NR-9 (Assessment and Control of Occupational Exposures to Physical, Chemical, and Biological Agents).
22.15.4 In locations where rock or ore is being drilled, cut, blasted, loaded, crushed, ground, unloaded, or transferred, water must be available in usable conditions for dust control purposes.
22.15.4.1 Drilling or cutting operations must be carried out using wet processes to prevent dust dispersion in the work environment.
22.15.4.2 If humidification is not possible due to the mineralogical characteristics of the rock, technical impossibility, or if water poses additional risks, devices or control techniques must be used to prevent dust dispersion in the work environment.
22.15.5 Dust-generating equipment exposing workers must use devices for its elimination or reduction and be maintained in operational condition.
22.15.6 The surfaces of machines, installations, and floors in areas where people and equipment transit must be continuously humidified or cleaned to prevent dust accumulation and dispersion in the work environment.
22.15.7 Workstations, where possible, must be enclosed or isolated and:
a) Have systems that maintain thermal and acoustic comfort conditions as provided in NR-17 (Ergonomics);
b) Allow work with the system hermetically sealed; and
c) Have systems that periodically renew the air.
22.16 Communication Systems
22.16.1 All underground mines must have a standardized communication system to permanently communicate the movement of machines or equipment, materials, and people in shafts, ramps, and inclined planes.
22.16.2 The start of personnel transport in shafts and inclined planes must be communicated by the communication system to the winch operator.
22.16.2.1 If there is no standardized code for the communication system in the mine, the basic signal code, both audible and visual, must follow the system shown in the table below:
| NUMBER OF SIGNALS | TYPE OF SIGNAL | ACTION |
|---|---|---|
| 1 | Long | Stop |
| 1 | Short | Up |
| 2 | Short | Down |
| 3 | Short | Entry or exit of people |
| 3+3+2 | Short | Go down slowly |
| 3+3+1 | Short | Go up slowly |
| 4 | Short | Start of personnel transport |
| 4+4 | Short | End of personnel transport |
| 5 | Short | The signaler will enter the cage |
| 1 | Continuous | Emergency |
22.16.2.2 The standardized communication system code must be posted in a visible location at all stop points and transport system operation stations.
22.16.3 When a communication system failure is detected, the transport of people and materials must be immediately halted, the supervisory staff informed, and the necessary repairs made.
22.16.4 Every communication system must confirm to the sender that the receiver has correctly received the message.
22.16.5 All operational, support, and emergency sectors of the mine must be interconnected by a communication system.
22.16.5.1 When telephone lines are used, they must be independent and protected from contact with the general electrical network.
22.16.6 In gassy mines, the communication system must be explosion-proof.
22.17 Signs
22.17.1 Signs must be maintained in perfect condition.
22.17.2 Tanks, storage areas, and areas where flammable materials, toxic substances, and materials capable of generating explosive atmospheres are used must be marked with signs indicating:
a) Danger zone;
b) Prohibition of open flames, smoking, or other devices that produce heat and sparks; and
c) Restricted access to authorized workers.
22.17.2.1 In storage areas for toxic substances and flammable fuel tanks, signs indicating the type of product and its maximum capacities must be posted in a visible location.
22.17.3 The identification of chemical products stored, handled, or used by the organization must follow the provisions of NR-26 (Safety Signs).
22.17.4 Access to underground mines, pits, benches, and ramps must be identified and marked with signs.
22.18 Electrical Installations
22.18.1 The organization must comply with NR-10 and the other provisions of this chapter.
22.18.2 Electrical supply cables and conductors used must be certified by a certification body accredited by the National Institute of Metrology, Standardization, and Industrial Quality (INMETRO).
22.18.3 Cables, installations, and electrical equipment must be protected against impacts, water, and the influence of chemical agents, considering their applications according to technical specifications.
22.18.4 The locations for installing transformers and capacitors, their panels, and respective operating devices must meet the following requirements:
a) Be ventilated and illuminated or, when installed in confined environments, be designed and constructed with appropriate technology;
b) When underground, be constructed and protected against falling materials and collision risks;
c) Be properly protected and marked with signs indicating the danger zone to warn that access is prohibited to unauthorized persons;
d) Not be used for purposes other than those established in the electrical design; and
e) Have an appropriate fire protection and firefighting system for the risk class, as per the design.
22.18.5 The energized terminals of transformers must be isolated by barriers or other physical means to prevent accidental contact.
22.18.6 The distribution panels or boards of electrical installations must:
a) Be sized with the capacity to install the components of the electrical circuits that constitute them;
b) Be made of materials resistant to the heat generated by the installation components;
c) Have live parts inaccessible and protected for unauthorized workers;
d) Have unobstructed access;
e) Be installed with enough space for servicing and operation;
f) Be identified and marked with signs regarding electrical risks;
g) Comply with the required protection class; and
h) Have their circuits identified.
22.18.7 The lockout during maintenance and repair operations of electrical installations must be done using a padlock and tags fixed in a visible location, containing at least the following information:
a) Time and date of the lockout;
b) Reason for maintenance; and
c) Name of the responsible person for the operation.
22.18.8 Emergency equipment and machines designed to maintain the continuity of electrical power supply and safety conditions at work must be kept permanently in working order.
22.18.9 Electrical power conductors must be installed so that they are not damaged by any means of transport, rock fragments, or by their own weight.
22.18.9.1 Electrical power conductors, when installed on the roof of galleries, must be at a height and location compatible with the safe transit of people, machines, and equipment and protected against accidental contact.
22.18.10 Automatic cable retrieval systems for mobile electrical equipment must be electrically bonded to the main equipment’s chassis.
22.18.11 In locations with the presence of flammable and explosive gases, electrical maintenance tasks must be performed under supervision in accordance with NR-10, with the power grid turned off and the activation switch locked, continuously monitoring gas concentrations to ensure the safety and health of the involved workers.
22.18.12 During electrical installations and maintenance, the settings and characteristics of safety devices cannot be bypassed.
22.18.13 It is the responsibility of the worker who identifies a defect in the electrical installations to inform their immediate superior so that the organization can take appropriate action.
22.18.14 Work on electrical networks between two or more points without visual contact between workers can only be performed using a communication system among them to prevent accidental energization.
22.18.15 Electrical network components that are no longer in use must be de-energized as defined in NR-10 and, if no longer used, must be removed.
22.18.16 In inclined planes, galleries, and shafts, cable and energized line installations must be executed with fixed supports for secure attachment.
22.18.17 Traction battery charging stations underground must observe the following conditions:
a) Be identified and marked with signs;
b) Be subject to fresh mine air ventilation, ensuring the airflow passes first over the transformers and then over the batteries, exiting directly into the ventilation return system;
c) Be separated from other electrical installations and equipment maintenance areas; and
d) Allow access only to authorized personnel carrying explosion-proof lamps.
22.19 Operations with Explosives and Accessories
22.19.1 All operations involving explosives and accessories must follow the manufacturer’s safety recommendations, as well as the provisions of NR-19 (Explosives), this Standard, and the explosives regulations of the Directorate of Controlled Products Inspection (DFPC) of the Brazilian Army.
22.19.2 In each mine where rock blasting with explosives is necessary, a blasting plan must be available, which includes:
a) Sketch with the distribution and arrangement of the holes;
b) Depth of the holes;
c) Planned quantity of explosives per hole and total used in the blasting;
d) Types of explosives and accessories used;
e) Detonation sequence;
f) Loading ratio;
g) Volume to be blasted;
h) Minimum return time after detonation; and
i) Indication of the loading risk area based on items “c,” “d,” “f,” and “g.”
22.19.2.1 The mine blasting plan must be prepared by a legally qualified professional.
22.19.3 The handling and use of explosive material must be carried out by a blaster, who may be assisted by a trained worker under their supervision.
22.19.4 The execution of the blasting plan, detonation operations, and related activities must be supervised and carried out by the blaster.
22.19.4.1 The blaster is responsible for:
a) Ordering the removal of explosives and accessories from the magazines or storage areas, transportation, and unloading at the worksite in the required quantities;
b) Guiding and supervising the loading of the holes, verifying the loaded quantity and the firing sequence;
c) Requesting the measurement of explosive gas concentrations before and during hole loading in mines or work fronts subject to gas emissions, respecting the limit stated in subitem 22.26.3.1 of this NR;
d) Guiding the connection of loaded holes with the initiation system;
e) Ensuring no one is in the blasting area before igniting the charge and leaving;
f) Ensuring proper operation of auxiliary ventilation and water spraying in development fronts;
g) Ensuring there are no misfires and, if any, taking the measures outlined in item 22.19.30 of this NR; and
h) Informing the area or service front supervisor of the completion of detonation activities.
22.19.5 Blasting with explosives must meet the following conditions:
a) Predefined detonation times displayed on visible signs at the mine access points;
b) The loading risk area must be marked, and work restricted to authorized personnel during loading;
c) Preceded by the activation of an audible, visual, or other more effective technological system;
d) The loading risk area must be evacuated and monitored before blasting;
e) Provision of a shelter for those triggering the detonation;
f) Cleaning the holes; and
g) If it is impossible to detonate partially or fully loaded fronts, the area must be evacuated and isolated until the reason for the detonation impediment ceases.
22.19.5.1 In underground operations, in addition to item 22.19.5 of this NR, the following conditions must be met:
a) Containment as per the mining plan;
b) Protected and operational ventilation system; and
c) Water sprinkler system in mining and development fronts for washing gases and dust during and after detonation.
22.19.5.1.1 When interconnecting two underground work fronts, the following criteria must be observed:
a) Total evacuation of personnel from both fronts during each detonation;
b) Non-simultaneous detonation of fronts; and
c) Establishment of a minimum safety distance for stopping one of the fronts.
22.19.5.2 In open-pit mines, in addition to item 22.19.5 of this NR, the following conditions must be met:
a) Measures to prevent the projection of rock fragments beyond the detonation area limits;
b) No detonations at night or when there is a risk of lightning; and
c) No detonations under low light conditions, except in exceptional cases with control measures provided in a risk analysis.
22.19.5.3 If detonation outside the predefined times is necessary due to the production process, the organization must implement a specific safety procedure for the detonation activity, observing items 22.19.5.1, 22.19.5.1.1, and 22.19.5.2 of this NR, as applicable.
22.19.6 The location, construction, storage, and maintenance of primary and secondary explosive and accessory magazines must comply with this standard and NR-19.
22.19.7 Explosive and accessory magazines underground must not be located near personnel access galleries or the main ventilation system of the mine.
22.19.8 Access to explosive and accessory magazines is only permitted to properly trained, qualified, or certified and authorized personnel, or those accompanied by such persons.
22.19.9 Storage locations for explosives and accessories underground must:
a) Contain no more than the quantity to be used in a 5 (five) day work period;
b) Be protected from accidental impacts;
c) Be locked under the responsibility of a legally qualified professional;
d) Be independent, separated, and marked;
e) Be marked on the mine plan, indicating their capacity; and
f) Be free from excessive moisture and have ventilation to maintain an appropriate temperature and minimize gas drift to work fronts in case of an accident.
22.19.9.1 Access within 20 meters of underground explosive and accessory storage locations is only permitted to workers in that area for gallery maintenance and storage work.
22.19.9.2 The containment system within a 25-meter radius of explosive and accessory storage locations must be made of non-combustible material, and no other material may be deposited within the storage locations.
22.19.10 The use of explosives must be controlled and recorded by the organization.
22.19.10.1 Explosive and accessory stock must be controlled and recorded by the organization, and the records must be periodically examined and checked by the blaster.
22.19.11 It is prohibited to keep explosives and initiating accessories outside the magazines or storage locations underground after completing the loading work.
22.19.11.1 Unused explosives and accessories must be immediately returned to their respective magazines or storage locations underground.
22.19.12 Explosives and accessories must be stored in their original packaging or appropriate containers on non-metallic, resistant, and moisture-free material.
22.19.12.1 Explosives and accessories must not be in contact with any material that could generate sparks.
22.19.13 Magazines and storage locations for explosives and accessories must be marked with warning signs reading “EXPLOSIVES” in visible locations near and at the access doors to these areas.
22.19.14 The vehicle used for internal movement of explosives and accessories must be equipped with a metallic connection from the body to the ground and protection to prevent metal parts from contacting explosives and accessories, observing the manufacturer’s recommendations.
22.19.14.1 Loading and unloading must be done with the vehicle turned off and locked.
22.19.15 Workers involved in the internal movement of explosives and accessories must receive specific training for their activity.
22.19.16 Internal movement of explosives, including detonating cords, simultaneously with accessories and other materials, as well as with unauthorized persons, is prohibited.
22.19.17 Internal movement of explosives and accessories must be done using appropriate containers.
22.19.18 The winch or elevator operator, if present, must be informed in advance of any movement of explosives and accessories inside shafts and inclined planes.
22.19.19 Explosives compromised in their condition, including those from misfires, must be destroyed according to the manufacturer’s instructions and the explosives regulations of the Directorate of Controlled Products Inspection of the Brazilian Army.
22.19.20 It is prohibited to use matches, lighters, open flames, or any instrument or tool that generates sparks during the handling, priming, and movement of explosives and accessories.
22.19.21 Only wooden, plastic, or copper tamping rods are permitted for loading holes.
22.19.22 Instruments and equipment used for electrical detonation and resistance measurement must be periodically inspected and calibrated, with the last inspection recorded.
22.19.23 In underground mines with emissions of flammable or explosive gases, the use of explosives is only permitted with procedures ensuring worker safety.
22.19.24 Priming of explosives is prohibited outside the work front.
22.19.25 The attachment of the detonator to the fuse must be done with a specific tool for this purpose.
22.19.26 Conductive wires used in electrical detonations must have the following characteristics:
a) Be appropriate for this application;
b) Be electrically insulated;
c) Contain no splices;
d) Be kept short-circuited until connected to the detonators;
e) Be connected to the detonation equipment by the blaster only after personnel have been removed from the detonation front; and
f) Have sufficient length to provide a safe distance for the blaster.
22.19.27 In mines with low relative humidity, subject to static electricity buildup, the blaster must use a grounding ring or another more effective technical solution during circuit assembly and electrical detonation.
22.19.28 For shaft and ramp deepening work, the following additional requirements must be met:
a) Movement of explosives and accessories to the blasting site can only occur separately and after all unauthorized personnel have been removed;
b) All electrical installations in the shaft or ramp must be turned off before connecting the electric detonators to the lead wire;
c) Detonation can only be triggered from the surface or intermediate levels; and
d) Winch and elevator operators must be properly informed of the start of loading with explosives.
22.19.29 Returning to the blasted front is only permitted after verifying the following conditions:
a) Dissipation of gases and dust, observing the minimum time determined by the ventilation plan and blasting plan;
b) Confirmation of area stability;
c) Marking and elimination of misfires; and d) Authorization from the blaster.
22.19.30 Upon detection or suspicion of misfires in the detonated material after the return of activities, the following measures must be taken:
a) Work must be immediately interrupted;
b) The area must be evacuated; and
c) Inform the blaster to take appropriate action.
22.19.30.1 The removal of misfires can only be performed by the blaster or, under their guidance, by a trained or qualified and authorized worker.
22.19.31 The removal of misfires can only be done using a device that does not produce sparks.
22.19.32 Remaining explosives and accessories from a loading must have their disposal planned in a procedure developed by the organization and defined by the Brazilian Army.
22.19.33 The reuse of explosives and accessories from misfires is prohibited, and their disposal must be planned in a procedure developed by the organization and defined by the Brazilian Army.
22.19.34 The use of failed holes is prohibited.
22.20 Activities with Floating Dredges
22.20.1 Floating dredges, in addition to the obligations established by specific legislation, must meet the following requirements:
a) the dredge platform must be equipped with a collective fall protection system with the dimensions provided in item 22.6.5 of this NR;
b) all equipment must be securely fixed to prevent displacement;
c) possess an audible alert for emergency situations;
d) be equipped with life jackets in a number corresponding to the occupants; and
e) have the maximum allowed load indicated in a visible location.
22.21 Hydraulic Dismantling
22.21.1 Workers and equipment performing the dismantling must be protected at an adequate distance to shield them from possible collapses or landslides.
22.21.2 Unauthorized persons are prohibited from entering areas where hydraulic dismantling is being carried out.
22.21.3 Workers in charge of dismantling must be protected by appropriate equipment for working in high humidity conditions.
22.21.4 In hydraulic dismantling installations, the following requirements must be observed:
a) pipes, fittings, and supports must be suitable for these purposes and equipped with a device to prevent hose whipping in case of accidental disconnection;
b) there must be support for the jetting equipment; and
c) the installation must have an emergency shutdown device for the pressure pump.
22.22 Ventilation in Underground Activities
22.22.1 Underground mines must have a mechanical ventilation system designed and developed by a legally qualified professional and be an integral part of the mining and development process of the mine.
22.22.1.1 The mechanical ventilation system project must be kept up to date.
22.22.2 The mechanical ventilation system, in areas where work activities and people circulation occur, must ensure continuous air renewal to meet the following minimum requirements:
a) supply the need for oxygen;
b) effectively dilute flammable or harmful gases and workplace dust; and
c) ensure air temperature and humidity suitable for human work.
22.22.3 The ventilation system must meet at least the following requirements:
a) have an emergency fan with sufficient power to maintain the requirements set out in items “a” to “c” of 22.22.2 of this NR;
b) the fan intakes must be protected;
c) the main and emergency fans must be installed to prevent air recirculation; and
d) have an alternative power supply system from an independent source to activate the emergency system in the following situations:
I – mines subject to the accumulation of explosive or toxic gases; and
II – mines where lack of ventilation endangers the safety of people during evacuation.
22.22.3.1 In the absence of power supply or an independent power source, the organization must ensure the immediate evacuation of people.
22.22.4 The mechanical ventilation system must be maintained in accordance with a maintenance plan developed under the responsibility of a legally qualified professional.
22.22.5 For each mine, a current ventilation flowchart must be developed and implemented, containing the location, flow rate, and pressure of the main and emergency fans, when these exist, and the direction of airflow, according to the ventilation project.
22.22.5.1 The ventilation flowchart must be available at the entrance of each mine.
22.22.6 The organization must implement the ventilation project through a Ventilation Plan (PV) in accordance with the mine’s mining, development, and operation plan, considering the safety and health of workers.
22.22.6.1 The PV must include updated schematic ventilation diagrams containing at least the following data:
a) location and flow rate of booster fans and auxiliary fans;
b) direction and airflow direction; and
c) location of all doors, barricades, curtains, dikes, partitions, and other ventilation control devices.
22.22.6.1.1 The schematic ventilation diagrams for each level must be posted in a visible location on the respective levels or in the mining panels, depending on the mining method.
22.22.7 All work fronts, in development and mining, must be ventilated by an air current that prevents workers’ exposure to contaminants above legal exposure limits.
22.22.8 The use of the same shaft or inclined plane for air intake and exhaust is prohibited, except during development work with tubed exhaust or adduction or through a device or system that prevents the mixing of the two airflows.
22.22.8.1 Pipes used for air exhaust or adduction must be kept in working condition.
22.22.8.1.1 In the event of perforations, tears, or any other situation where there is a loss of airflow in the pipes that interferes with the effectiveness of the ventilation system, activities must be interrupted until proper correction or replacement of the damaged pipe is made.
22.22.9 In areas where people are transiting or working, the oxygen concentration in the air must not be less than 19% by volume.
22.22.10 At the main air intakes of levels and active work fronts, devices must be installed that allow immediate visualization of airflow direction.
22.22.11 The total flow of fresh air in the mine must meet the sum of the ventilation needs of all active work fronts, dimensioned as specified in this standard and in the PV.
22.22.12 In underground mines, internal combustion engines used must be diesel-powered, respecting the following conditions:
a) effective ventilation system in all operating locations;
b) air filtration systems for the air intake of the engine, with cooling systems and exhaust gas washing or catalysts;
c) flame and spark prevention system for the engine exhaust air, in mines with explosive gas emissions or in the transport of explosives;
d) periodic air sampling program, at intervals not exceeding one month, at the most representative points of the affected area, sampling at least nitrous gases, nitrogen oxide, carbon monoxide, and sulfur dioxide; and
e) periodic sampling program, at intervals not exceeding three months, of particulate materials and exhaust gases from engines under full load and no-load conditions, sampling at least nitrous gases, nitrogen oxide, carbon monoxide, and sulfur dioxide.
22.22.13 Vehicles and internal combustion equipment used in underground mines must be exclusively diesel-powered with sulfur content up to 10 ppm.
22.22.14 In coal mines with grisu emissions or flammable gases, the vitiated air current must be directed upward.
22.22.14.1 The vitiated air current can only be directed downward with technical justification.
22.22.15 The fresh air flow rate in coal mine galleries consisting of the last broken cross-cuts, without the use of diesel-powered machines and equipment, must be at least 250 m³/min.
22.22.15.1 In active mining or development fronts without the use of diesel-powered machines and equipment, the fresh air flow rate must be dimensioned at a rate of 15 m³/min/m² of the respective work front area.
22.22.15.2 In active mining panels without the use of diesel-powered machines and equipment, the fresh air flow rate must be dimensioned at a rate of 15 m³/min/m² of the area of each front where mining unit operations are occurring.
22.22.15.3 In other work fronts without the use of diesel-powered machines and equipment, the minimum allowable fresh air flow rate must be 85 m³/min, and the auxiliary ventilation system must be installed to prevent air recirculation.
22.22.16 In other mines without the use of diesel-powered machines and equipment, except for radioactive minerals regulated by specific legislation, the fresh air flow rate in work fronts must be at least 2 m³/min per person.
22.22.17 In mines, including coal mines, and other underground activities with the use of diesel-powered machines and equipment, the fresh air flow rate will be dimensioned according to the provisions in Table I of Annex IV of this NR, with the greater flow rate prevailing.
22.22.17.1 For coal mines, item “c” of Table I of Annex IV of this NR does not apply.
22.22.18 The air velocity in the underground must not be less than 0.2 m/s nor more than an average of 8 m/s where people circulate.
22.22.18.1 In coal mines, the air velocity must not exceed 5 m/s.
22.22.18.2 Special cases that require an increase in the upper velocity limit up to 10 m/s must be technically justified by the legally qualified professional responsible for the PV.
22.22.18.3 In shafts, drill holes, chimneys, or galleries exclusively for ventilation, the velocity can exceed 10 m/s.
22.22.19 Whenever passage through ventilation doors poses risks due to pressure differences, two doors in series must be installed so that one remains closed while the other is open during the transit of people or equipment.
22.22.19.1 There must be an opening in the ventilation doors to equalize the pressure between the doors.
22.22.19.2 The assembly and disassembly of ventilation doors will only be permitted with authorization from the legally qualified professional responsible for the mine.
22.22.20 In the main air current, structures used to separate fresh air from vitiated air at crossings must be constructed of masonry or fire-resistant material or coated with fireproof material.
22.22.20.1 Ventilation partitions must be kept in good sealing condition to provide adequate and sufficient airflow to the work fronts.
22.22.21 The installation and operation modes of the main and emergency fans must be defined and established in the ventilation project included in the mining plan.
22.22.22 The main and emergency fans must have their air pressure monitored by the organization.
22.22.23 The main fan must have an alarm device indicating its stoppage.
22.22.24 The motors of fans installed in fronts with the presence of explosive gases must be explosion-proof.
22.22.25 All development galleries, after 10 meters of advance, and underground works without communication or in a dead-end must be ventilated by an auxiliary ventilation system, and the fans used must be installed to prevent air recirculation.
22.22.25.1 The distance of 10 meters can be extended to 15 meters with a technical report, prepared by a legally qualified professional, proving that the conditions of item 22.22.2 of this NR are met.
22.22.25.2 The fan start switch must be in the fresh air current.
22.22.26 For each placement or removal of auxiliary ventilation, a specific diagram must be developed, observing the PV.
22.22.27 Auxiliary ventilation must not be turned off while there are people working at the service front.
22.22.27.1 In case of maintenance on the auxiliary ventilation, the following requirements must be followed:
a) personnel withdrawal, allowing only the presence of the maintenance team; and
b) application of a specific procedure for this situation.
22.22.28 Ventilation using only compressed air is prohibited, except in emergencies or if the air is treated to remove impurities.
22.22.28.1 The discharge air from drills is not considered ventilation air.
22.22.29 Personnel involved in ventilation and the entire mine supervision level working underground must receive training in basic mine ventilation principles.
22.22.30 To verify the effectiveness of the mine ventilation system, measurements of air velocity and flow, relative humidity, and temperature must be performed at least monthly by a qualified professional, covering at least the following points:
a) ventilation entry paths;
b) mining and development fronts; and
c) main fan.
22.22.30.1 Measurement results must be recorded in proper logs and available to workers or their representatives and competent authorities.
22.22.31 In the case of mines with grisou or toxic, explosive, or flammable gases, concentration control must be carried out every shift at operating work fronts and important ventilation points.
22.22.32 The underground mine ventilation system must be governed and equipped with procedures or devices that:
a) prevent combustion gases from surface fires from entering the interior; and
b) ensure that combustion gases or other toxic gases generated inside due to fire are not carried to work fronts or are adequately diluted.
22.23 Processing
22.23.1 Processing plants must have their circulation and exit routes identified and visibly marked.
22.23.2 Processing machines and equipment, in terms of physical arrangements and installation locations, in addition to the provisions in chapter 12.2 of NR-12, must be spaced sufficiently apart to allow:
a) the diversion of material in case of defects; and
b) the interposition of other equipment necessary for repairs and maintenance.
22.23.3 It is mandatory to adopt procedures with specific safety measures for working inside the following machines and equipment:
a) feeders;
b) mills;
c) looms;
d) calenders;
e) continuous conveyors;
f) thickeners;
g) storage and transfer silos;
h) crushers; and
i) others used in cutting, turning, grinding, mixing, mass storage, and transport operations, where applicable.
22.23.3.1 Maintenance, inspection, repairs, cleaning, adjustment, and other necessary interventions on processing equipment must be carried out in accordance with NR-12.
22.23.3.1.1 Only the person responsible for the lockout can unlock the machines and equipment.
22.23.3.1.1.1 Exceptionally, when unlocking cannot be performed by the responsible person, the organization may authorize the unlocking of the machines and equipment, with the authorization recorded.
22.23.4 In manual auxiliary work activities feeding crushers or other equipment by gravity, the worker must be connected to an individual fall protection system, in accordance with NR-35.
22.23.5 Sample collection must meet the following requirements:
a) comply with specific safety procedures;
b) the collection sites must have safe means and conditions for the activity; and
c) be performed by a trained worker.
22.23.6 Dumping areas must be marked, lit, and delineated.
22.23.6.1 In dumping conducted directly in locations with a risk of falling people and equipment, a collective protection system against accidental falls must be installed, with resistance to withstand the required stresses, defined in a project prepared by a legally qualified professional.
22.23.6.1.1 For existing installations, the resistance of collective fall protection systems must be certified by a legally qualified professional.
22.23.7 Areas with heap leaching processes and their basins must be fenced and marked, prohibiting unauthorized access.
22.23.7.1 Leaching processes must be carried out by trained workers and under the technical responsibility of a legally qualified professional.
22.24 Disposal of Waste, Tailings, and Products
22.24.1 Waste, tailings, and product deposits must be designed by a legally qualified professional and implemented and maintained under the supervision of a legally qualified professional and comply with current regulations.
22.24.1.1 Piles of final products temporarily stored in the yards of ore treatment facilities are excluded from the requirements of Chapter 22.24 of this NR.
22.24.2 Access to product, waste, tailings deposits, and mining dams must be marked and restricted to personnel necessary for the work conducted there.
22.24.3 The design, construction, maintenance, and operation of any facilities of the organization located downstream of a dam subject to flooding in case of a breach are prohibited, as such situations are considered serious and imminent risks and subject to the interdiction of the organization’s facilities that do not comply with this item. (Effective date amended by art. 2 of MTE Ordinance No. 836, of May 27, 2024 – Effective as of August 26, 2024)
22.24.3.1 For new dams, the prohibition provided in item 22.24.3 of this NR does not apply until the reservoir filling begins. (Effective date amended by art. 2 of MTE Ordinance No. 836, of May 27, 2024 – Effective as of August 26, 2024)
22.24.3.2 Essential sanitary facilities for workers operating in areas downstream of the dam subject to flooding in case of a breach are excluded from the provisions of item 22.24.3 of this NR. (Effective date amended by art. 2 of MTE Ordinance No. 836, of May 27, 2024 – Effective as of August 26, 2024)
22.24.4 The construction of waste, tailings, and product deposits must be preceded by geotechnical, hydrological, and hydrogeological studies.
22.24.5 Waste, tailings, and product deposits must be monitored under the supervision of a legally qualified professional and have monitoring of water percolation, groundwater level, and structure movement, as defined in the project and stability study.
22.24.6 Waste, tailings, and product deposits must meet the minimum stability safety factor established in national technical standards and ANM regulations.
22.24.7 Organizations with dams included in the National Dam Safety Policy (PNSB) must keep the Dam Safety Plan, including the Emergency Action Plan for Mining Dams (PAEBM), available to the Specialized Service in Safety and Occupational Medicine (SESMT), when available, and the predominant category’s union representation.
22.24.8 The schedule of Routine Inspections must be made available in advance to the SESMT, when available.
22.24.9 The Regular Safety Inspection Report of the dam and the respective Stability Condition Declaration (DCE) and the PAEBM Compliance and Operability Report and respective Compliance and Operability Declaration (DCO), as provided in ANM regulations, must be made available to the SESMT, when available, and sent to the union representation upon request within 10 (ten) days.
22.24.10 The organization must inform the SESMT, when available, the predominant category’s union representation, and the regional occupational safety and health authority of any anomalies that trigger a special inspection, as required by the ANM.
22.24.11 In situations of serious and imminent risk of collapse of waste, tailings, and product deposits, the risk areas must be evacuated and isolated, and the process evolution must be monitored, informing all potentially affected personnel, as defined in the Emergency Response Plan (PAE).
22.24.12 The final or temporary disposal of toxic or hazardous products must be carried out safely and in accordance with current regulations from competent authorities.
22.24.13 Deposits of toxic or hazardous chemical substances and products must have a containment system marked and compatible with the stored volume.
22.24.14 Within the safety perimeter of the piles, as defined in the project and stability study, the design, construction, maintenance, and operation of facilities intended for production, auxiliary, administrative, living, health, and recreational activities are prohibited. (5 years implementation period for piles already built and in operation according to Art. 3 of MTE Ordinance No. 225, of February 26, 2024)
22.25 Lighting
22.25.1 Workplaces, circulation areas, and transportation of people must have natural or artificial lighting systems appropriate to the activities carried out.
22.25.1.1 In underground settings, a stationary lighting system is mandatory, maintaining the following minimum average illumination levels in the areas listed below:
a) 100 lx (one hundred lux) at the bottom of the shaft;
b) 200 lx (two hundred lux) in the machine room;
c) 50 lx (fifty lux) in main pathways;
d) 200 lx (two hundred lux) at loading, unloading, and transit points over continuous conveyors;
e) 200 lx (two hundred lux) at the crushing station; and
f) 300 lx (three hundred lux) in the office and repair workshops.
22.25.2 Surface installations that depend on artificial lighting, where a failure could endanger people’s safety, must be equipped with emergency lighting that meets the following requirements:
a) automatic activation in the event of a failure of the main system;
b) be independent of the main system;
c) provide sufficient illumination to allow people to exit the installation; and
d) be tested and maintained in working condition.
22.25.2.1 If emergency lighting installation is not possible, workers must have individual lighting equipment.
22.25.3 The following underground activities must have supplementary lighting in addition to individual lighting:
a) checking for material fall hazards;
b) checking for geological faults and discontinuities;
c) scaling of loose rocks and unstable blocks; and
d) interventions in electrical and mechanical installations at work fronts.
22.25.4 When lighting is required inside explosive and accessory storage depots and locations, it must be suitable for classified areas.
22.25.5 During nighttime work or low-visibility conditions in open-pit mines, operational dumping or unloading fronts must have sufficient artificial lighting.
22.25.5.1 When atmospheric conditions prevent visibility, even with artificial lighting, work and the traffic of vehicles and mobile equipment must be suspended.
22.25.6 The use of individual flashlights is mandatory in the following conditions:
a) for access and work in underground mines; and
b) for nighttime movement in the operation area of mining, dumping, and loading in open-pit mines.
22.25.6.1 In mines with explosive gases, only safety flashlights suitable for classified areas are allowed.
22.25.6.2 Spare flashlights in working condition must be available at points near the workplaces.
22.25.7 Special measures must be taken to protect vision when working with minerals with a high reflectance index.
22.26 Fire and Accidental Explosion Prevention
22.26.1 In mines and installations subject to gas emissions or the generation of suspended particulate, explosive or flammable materials, the PGR (Risk Management Program) must include actions for fire and accidental explosion prevention.
22.26.1.1 Fire prevention and firefighting actions and accidental explosion prevention must be implemented by the organization and include at least:
a) periodic measurements, with intervals determined based on the characteristics of the gases, which may be modified at technical discretion;
b) updated records of measurement results available to workers; and
c) designation of a person responsible for the measurements.
22.26.2 In underground mines, the methane concentration in the work environment must not exceed one percent by volume or equivalent.
22.26.2.1 If methane concentration exceeds this level, work activities must be suspended, and the potentially affected mine areas must be immediately evacuated, informing the immediate supervisor.
22.26.2.1.1 During the suspension of activities, only work to reduce methane concentration is allowed.
22.26.2.2 If methane concentration reaches or exceeds two percent by volume or equivalent, the entry of people into the potentially affected mine areas must be immediately prohibited.
22.26.2.2.1 Any intervention in the prohibited areas referred to in item 22.26.2.2 of this NR is only allowed by remote technological means that do not involve human work in direct contact with the potentially affected mine areas.
22.26.3 The methane concentration in the airflow must be controlled periodically, according to a specific procedure established by the organization.
22.26.3.1 Any type of blasting is prohibited above 0.8 percent by volume of methane in the air.
22.26.4 The organization must provide quick escape personal protective equipment for everyone accessing underground mines.
22.26.5 In all underground mines, in addition to providing quick escape personal protective equipment, non-combustible fixed or mobile refuge chambers must be available, located so that all workers at development and mining fronts do not have to travel more than 750 meters to access them, with the capacity to shelter workers in case of emergency for a minimum time provided in the PAE (Emergency Response Plan), considering the PV (Ventilation Plan), and having the following minimum characteristics:
a) a door capable of being hermetically sealed;
b) a communication system with the surface;
c) potable water, food, and a breathable air system sufficient for the planned time of use;
d) easily accessible and identifiable;
e) a toilet bowl with a seat and lid and a sink; and f) first aid materials.
22.26.5.1 The distance defined in item 22.26.5 of this NR may be increased to up to 1,200 meters with technical justification from a legally qualified professional.
22.26.5.2 For work carried out at service fronts, the locations of the refuge chambers and the duration of stay must be defined by a legally qualified professional, considering the PV, and the technical justifications and calculation memories must be included in the PAE.
22.26.5.3 The location of the refuge chambers must be georeferenced.
22.26.6 Fire prevention must be promoted in all mine facilities through the following measures:
a) prohibition, in underground mines, of carrying or using any object that produces fire or sparks, except those necessary for work activities and carried only by authorized workers;
b) proper disposal of trash and disposable material with flammable potential in any mine facility;
c) prohibition of storing flammable products, explosives, and accessories near transformers, boilers, and other equipment and installations involving electricity and heat;
d) work involving welding, cutting, and heating with an open flame can only be performed when all adequate means for preventing and fighting potential fires are provided; and
e) prohibition of smoking underground.
22.26.7 The carrying and use of carbide lamps are prohibited underground.
22.26.8 In underground mines where a conveyor belt transport system is used, a fire-fighting system must be installed near its drive system and drums.
22.26.9 In fresh air intake areas, additional precautions must be taken to prevent fires and their spread.
22.26.10 Near underground mine entrances, combustible and flammable or explosive product depots must not be installed.
22.26.11 Combustible and flammable product depots inside underground mines must be installed so that, in case of fire and explosion, combustion products do not contaminate the mine’s ventilation air.
22.26.12 Every mine must have fire-fighting systems or devices, as defined in NR-23 (Fire Protection) and inspected under the responsibility of a legally qualified professional, at least annually or as provided in the fire-fighting project.
22.26.13 Fire-fighting systems or devices must be permanently identified and located in appropriate and visible places, as defined in the project.
22.26.14 Workers must receive instructions on fire prevention and firefighting procedures and basic first aid.
22.26.15 Fire-fighting devices must be available at the entrances to explosive and accessory depots, as per NR-23.
22.26.16 Work in classified areas must use machines, equipment, materials, and installations suitable for the work environment atmosphere.
22.27 Prevention of Explosive Dust in Underground Coal Mines
22.27.1 In underground coal mines, the organization must identify dust generation sources and adopt preventive measures to reduce the risk of explosion.
22.27.1.1 Preventive measures should include humidification at dust generation points.
22.27.1.1.1 Alternative preventive measures may be adopted, provided they are technically justified by a legally qualified professional.
22.27.1.2 Existing ignition sources in workplaces must be isolated, and the equipment used must be explosion-proof certified.
22.28 Flood Protection
22.28.1 The organization must adopt measures to prevent accidental floods in its facilities that could compromise worker safety.
22.28.1.1 In underground mines, additional safety measures must be adopted, and the following steps must be taken:
a) conduct hydrogeological studies to guide preventive measures to avoid flooding;
b) implement an adequate communication system for flood situations in access or exit galleries; and
c) monitor and control the quantity of pumped water and its variations over time.
22.29 Radioactive Equipment
22.29.1 The use and decommissioning of radioactive sources or gauges must follow the guidelines of the National Nuclear Safety Authority.
22.29.2 Organizations using radioactive sources or gauges must maintain their Radiation Protection Plan and calibration certificates of measuring devices available for inspection.
22.29.3 All radioactive sources and areas with dose rates above the limits allowed for the public must be marked with signs.
22.29.4 Workers exposed to ionizing radiation and those who transit through areas with radioactive sources must be informed about the equipment, its operation, and its risks.
22.30 Emergency Response Plan (ERP)
22.30.1 Every mine must develop, implement, and maintain an updated Emergency Response Plan that includes at least the following requirements and applicable scenarios:
a) identification of major risks;
b) procedures for operations in case of:
I – fires;
II – floods;
III – explosions;
IV – collapses;
V – power supply interruption to the main mine ventilation system;
VI – major accidents;
VII – mining dam failure, as provided in the PAEBM;
VIII – other emergency situations depending on the mine’s characteristics, products, and supplies used; and
IX – structure collapse in piles; and
c) location of equipment and materials needed for emergency operations and first aid provision;
d) description of the composition and operating procedures of emergency brigades to act in situations described in items I to VIII of clause “b” of this item;
e) periodic training of emergency brigades at intervals not exceeding twelve (12) months, with theoretical content and practical applications;
f) periodic simulations of rescue situations involving the mine’s contingent directly affected by the event;
g) definition of areas and facilities built and equipped for people’s refuge and first aid provision;
h) definition of emergency communication and signaling systems, covering the internal and external environment;
i) coordination of the organization with civil defense agencies; and
j) establishment of a system that allows knowing, precisely and at any time, the names and probable locations of all people underground.
22.30.2 Annual simulations of the emergency plan must be conducted, mobilizing the mine’s directly affected contingent.
22.30.2.1 Simulated exercises may be considered part of the practical applications of periodic training.
22.30.3 If an emergency situation defined in clause “b” of item 22.30.1 of this NR is detected, the entire risk area must be isolated, and people not directly involved in the emergency response must be evacuated to safe areas.
22.31 Emergency Routes and Exits in Underground Mines
22.31.1 Every active underground mine must have at least two access routes to the surface, a primary route and an alternative or emergency route, separated and connected by secondary routes, so that the interruption of one does not affect traffic through the other.
22.31.1.1 Underground, workplaces must allow for the immediate evacuation of workers in safe conditions.
22.31.1.2 The provisions of item 22.31.1 of this NR do not apply during the mine’s opening phase.
22.31.2 In underground mines, main and secondary routes must provide conditions for every person to have an alternative route to the two surface access routes from the workplaces, one of which is the emergency path.
22.31.3 Emergency routes and exits must be directed as directly as possible to the outside, in a safe zone or predetermined and signposted concentration point.
22.31.4 Emergency routes and exits, as well as circulation routes and the doors giving access to them, must be signposted and kept unobstructed, as per NR-23.
22.31.5 Inclined planes and chimneys intended for emergency exits must have stairs built and installed as prescribed in chapter 22.10 of this NR.
22.31.6 In underground mines with activities started from the effective date of this standard and in the development of new fronts and levels in mines already in operation, emergency exits cannot be installed in exhaust shafts.
22.31.6.1 In operating underground mines with emergency exits installed in exhaust shafts, technical measures must be implemented as established in a procedure to redirect the contaminated air flow in an emergency.
22.32 Suspension and Resumption of Activities in Mines
22.32.1 When temporarily or permanently suspending mining operations, the organization must formally notify the Regional Labor and Employment Superintendency of its Federal Unit.
22.32.2 Suspended mines and already mined or deactivated areas must be fenced and signposted or controlled to prevent inadvertent access, in accordance with current legislation.
22.32.3 To resume mining activities after temporary or permanent suspension, the organization must conduct a new Occupational Risk Management, as provided in chapter 1.5 of NR-1.
22.33 Internal Committee for the Prevention of Accidents and Harassment in Mining (CIPAMIN)
22.33.1 Organizations employing workers must establish and maintain an Internal Committee for the Prevention of Accidents and Harassment in Mining (CIPAMIN) in each establishment, as prescribed in this NR-5 (Internal Committee for the Prevention of Accidents and Harassment – CIPA), where applicable.
22.33.2 CIPAMIN shall be composed of representatives of the employer and employees, along with their respective alternates, according to the minimum proportions specified in Table II of Annex IV of this NR.
22.33.2.1 The composition of CIPAMIN should follow criteria that ensure representation of sectors posing higher risk or having a higher number of work accidents.
22.33.2.1.1 The sectors of higher risk must be defined by CIPAMIN based on PGR data, the analytical report of the Occupational Health Medical Control Program (PCMSO), safety and health performance indicators monitored by SESMT (if available), and other available safety and health data and information.
22.33.2.2 If the establishment does not fall under Table II of Annex IV of this NR and is not covered by SESMT as per NR-4 (Specialized Services in Occupational Health and Safety), the organization must appoint and train a representative from among its employees to assist in implementing preventive actions in workplace safety and health and fulfilling CIPAMIN’s objectives, as per NR-5.
22.33.3 Employee representatives in CIPAMIN will be elected by employees following the procedures established in NR-5, respecting the criteria in subitem 22.33.2.1 of this NR.
22.33.3.1 To comply with the criteria in subitem 22.33.2.1 of this NR for CIPAMIN composition, CIPAMIN will designate areas to be covered by individual employee representation, except during the initial implementation, where the organization will designate the areas.
22.33.3.1.1 CIPAMIN must be composed to ensure representation of all sectors of the establishment, and, if necessary, may group related areas or sectors.
22.33.3.2 Interested candidates must register to represent their area or work sector.
22.33.3.3 The election will be conducted by area or sector, and employees will vote for candidates registered in their area or work sector.
22.33.3.4 The candidate with the most votes in each area or work sector will become the primary CIPAMIN representative.
22.33.3.5 The alternate representative, considering Table II of Annex IV of this NR, will be the candidate with the most votes among all other candidates, regardless of the area or work sector.
22.33.4 CIPAMIN’s duties, in addition to those in NR-5, include:
a) establishing ongoing negotiations within its representations to recommend and request control measures from the employer;
b) monitoring the implementation of control measures and the action schedule established in the PGR and PCMSO;
c) participating in periodic workplace inspections scheduled by the organization or SESMT (if available), following a schedule negotiated with the employer;
d) requiring SESMT (if available) or the employer to provide prior notice of the impact of new projects or significant changes in the work environment or process on worker safety and health; and
e) including topics related to the prevention and combat of harassment and other forms of workplace violence in its activities and practices.
22.33.5 The organization must provide training for the appointed representative and CIPAMIN members, both primary and alternate, before they assume their roles, as defined by NR-5.
22.33.6 The organization must also provide additional training, lasting 20 (twenty) hours, during the term of office, covering safety inspection methodology and other practices defined by the organization.
22.33.7 Appointed representatives from contracted organizations must participate in the meetings of the contracting organization’s CIPAMIN.
22.34 Sanitary and Comfort Conditions in Workplaces
22.34.1 Comfort and hygiene conditions in workplaces are those established in this standard and NR-24 (Sanitary and Comfort Conditions in Workplaces).
22.34.2 Sanitary facilities, located no more than 250 meters (820 feet) away, must be provided at work fronts, separated by gender, and consisting of a toilet and washbasin for every group of 20 workers or fraction thereof, considering the number of workers in the largest shift. Chemical toilets with flushing or waste isolation mechanisms, ventilation, handwashing and drying materials (no communal towels allowed), must be used, and hygiene must be ensured each shift with daily waste removal.
22.34.2.1 For short-duration work activities, where a vehicle is maintained for worker transport, the distance to sanitary facilities can be extended to up to 1,000 meters (3,280 feet).
22.34.3 Changing and storing work clothes underground is prohibited.
22.34.4 Workplaces, stations, and work fronts must ensure workers have access to potable, fresh, and hygienically maintained water, which can be provided through an individual, thermal, hermetically sealed, and sanitized container.
22.34.5 The organization must provide underground workers with meals suitable for the nature of their work, as per current legislation.
22.34.6 If food is provided underground, the organization must maintain an appropriate location that meets safety, hygiene, and comfort standards for meals.
22.35 General Provisions
22.35.1 When the organization provides transportation for personnel, either directly or through contracted organizations, it must ensure that transportation is conducted in standardized vehicles, guaranteeing comfort, convenience, and safety for the workers.
22.35.2 The organization must keep records of occupational accidents and illnesses updated, ensuring full access to this documentation for CIPAMIN and SESMT, if available.
22.35.2.1 Occupational accidents and illnesses must be analyzed according to subitem 1.5.5.5 of NR-1.
22.35.2.2 In the event of a fatal accident, the following measures are mandatory:
a) immediately notify the competent police authority and the regional authority responsible for occupational safety and health; and
b) isolate the area directly related to the accident, maintaining its conditions until it is released by the competent police authority.
22.35.3 The design, construction, maintenance, and operation of facilities intended for administrative, living, health, and recreational activities of the company or Mining Concession Permit Holder are prohibited if located in areas downstream of dams that are subject to flooding in case of rupture. Such situations are considered of serious and imminent risk and may result in the interdiction of the company’s or Mining Concession Permit Holder’s facility that does not comply with this sub-item. (Inserted by MTE Ordinance No. 836, of May 27, 2024 – Temporarily effective until August 25, 2024)
22.35.3.1 For new dams, the prohibition provided for in item 22.35.3 does not apply until the moment the reservoir begins to be filled. (Inserted by MTE Ordinance No. 836, of May 27, 2024 – Temporarily effective until August 25, 2024)
22.35.3.2 The following facilities are considered living areas:
a) sanitary facilities;
b) changing rooms;
c) accommodation;
d) dining area;
e) kitchen;
f) laundry;
g) leisure area; and
h) first aid station.
(Inserted by MTE Ordinance No. 836, of May 27, 2024 – Temporarily effective until August 25, 2024)
22.35.3.3 The essential sanitary facilities for workers operating in areas downstream of dams subject to flooding in case of rupture are exempt from the provisions of item 22.35.3. (Inserted by MTE Ordinance No. 836, of May 27, 2024 – Temporarily effective until August 25, 2024)