AMIT 129: Lesson 7 Mine Explosives and Blasting

Objectives

Upon completion of this lesson students should be able to:

  • Describe types of explosives.
  • Explain the basics of handling explosives.
  • Explain the basics of toxic fumes.
  • Demonstrate safe work procedures.

Reading & Lecture

Mine Blasting

Blasting is the process of breaking rocks into small pieces by use of explosives.

Types of Explosives:

  • Explosives based on chemical nature
  • Explosives based on availability

Blasting in an open cut mine.

Explosives

Explosives Types

The most important responsibility of the blaster in charge is to prepare and fire safely. They are to practice safety in transportation, storage, handling, and the proper use of explosives.

Mine Explosives

 

  • Black Powders (Early Times) – SN + Sulfur + Carbon
  • Dynamite – NG + Wood Pulp (or SN)
  • ANFO (Blasting Agents) – Ammonium Nitrate + Fuel Oil
  • Water Gel, Slurry & Emulsion
  • Detonators (Blasting Caps) – Electric, NONEL & Electronic
  • Safety Fuses
  • NONEL (Shock) Tubes
  • Detonating Cords
  • Primers & Boosters

 

Packaged Emulsions

Hazards in Use of Explosives

 

A. Transportation hazards

  1. The vehicle used to transport explosives should be in good operating condition. If the vehicle were to get a flat tire or lose its brakes It would lead to a serious hazard for everyone. The cargo space in which the explosives are stored should be of non-sparking material. If the vehicle got into an accident with damage to the cargo area, you would want to minimize any sparks that could set off the explosives.
  2. Detonators and explosives should be kept apart by at least four inches of hardwood, or transported separately. If a detonator were to accidentally fire this would prevent it from setting off any explosives.
  3. Explosives should be transported at times when the fewest number of people will be endangered. During shift change or before or after personnel are transported into or out of the mine is usually a good time to bring explosives into the mine.
  4. Explosives should not be stacked higher than the sideboards of the vehicle. If the vehicle were to hit a bump some boxes could fall off the side.
  5. No smoking is permitted on or near the vehicle. Hot ashes or flames pose a danger when mixed with powder.
  6. If ANFO or any other powder is spilled it should be immediately cleaned up.
  7. Do not ride on the cage when it is being used to transport explosive material.
  8. Vehicles should be driven carefully and excessive speeds should be avoided. Do not drive over unbridged power cables.
  9. Vehicles loaded with explosives should not drive into any maintenance area where sparks from welding or stray electric currents could set off explosives.

 

B. Detonator Hazards

  1. Do not let leg wires and detonators come into contact with electrical equipment, wires or rails. These may carry enough of a current to set off the charge.
  2. Caps can deteriorate and become more sensitive because of age. Caps may also become useless from such damage as being kinked, exposed to extreme heat, or contaminated with water. They should be properly disposed but only by experienced powdermen.

 

C. Magazine Hazards

  1. Magazines must be built in dry, isolated areas of the mine so as to be well ventilated, bullet-proof, locked, and have non-sparking material on the inside wall. It must be marked with a sign located in such a place that if a bullet were to be fired into it the bullet would not pass into the stored powder.
  2. Flammable materials such as fuel or oil should not be stored near a magazine.
  3. Smoking in and around a magazine is prohibited.
  4. Detonators and explosives should not be stored together in the same magazine. Separate magazines for them should be at least 25 feet apart.
  5. The magazine must be kept clean of ti ash, empty boxes, and paper at all times. They are both a fire hazard and a cause of slips and falls.
  6. No electric wiring or open lights should be taken into a magazine.
  7. Surplus or loose explosives should not be left in unsecured areas such as cuts, passes, or by the outside walls of the magazine.

Non-electric Detonators

D. Blasting Hazards

Misfires

A misfire is a loaded hole that fails to fire. The procedure following firing a round is that the blaster or supervisor will inspect the muck pile for misfires. No one else is permitted to enter the area until the all-clear signal is given.

  1. If the blaster finds a misfire he will attempt to re-wire and detonate it or flush it out of the drill hole with water and then dispose of it.
  2. After the blast the rock pile should be hosed down with water to keep the dust settled.
  3. In the event the misfire is completely covered by rock, the blaster may not see it. This results in a very dangerous situation. Do not attempt to move it yourself. If you discover a misfire in the rock, work should stop immediately, the area should be cleared and guarded, and the supervisor should be contacted.
  4. Toxic fumes may be found after detonation. You can avoid these fumes by remaining out of the blast area until ventilation dilutes the gases and carries them out of the mine.
    • Carbon monoxide can be detected by observing one of the first symptoms of such poisoning – headache pain.
    • Explosives containing nitroglycerine or other nitro compounds may burn rather than detonate. One gas resulting from this is nitrogen dioxide which is extremely dangerous to your lungs in small amounts. It has a burned powder odor.
    • Wet ANFO will generate nitrous oxide fumes.
  5. After the blast the rock pile should be hosed down with water to keep the dust settled.

Overshooting

Overshooting results from either an excessive use of explosives, an improperly sized drill hole, or holes that are not properly placed according to the delay pattern. Undershooting is just the opposite. Overshooting weakens the remaining deposit making it susceptible to falls and may require use of supports. Undershooting results in an uneven face and creates haulage problems by having to move larger sized rocks.

 Fly Rock

Fly rock consists of pieces of rock blown from the shot area by the explosive force. This rock can be lethal because of its , weight and velocity of travel. Flyrock is also caused by a blowout. When a blast hole is not drilled deep enough into the rock, the explosive force blows the rock out into the drift or work area.

Flyrock has killed and injured people
A link to the CDC’s guide to flyrock awareness

Electrical Hazards

Electrical hazards are present if the mine uses electric blasting caps.

  1. Natural sources like static electricity or lightning storms.
  2. Man-made sources like stray electricity and radio transmitters.
  3. Only special galvanometers should be used to test continuity. Regular galvanometers may set off the charge. If you find a cap in the muck pile do not attempt to test the leg wires – only experienced powdermen are equipped to do such work.
  4. Any power equipment with leaking current presents a hazard.
  5. Static charge built up from pneumatic loading equipment.

Bootlegs

Never drill into a bootleg – it could contain a charge of powder that might detonate when struck by the drill steel. Prior checks of the hole may have accidentally not detected the powder, so do not take any shortcuts.

Safe Work Procedures with Explosives

Training

Task training is given to the powder crew to increase their technical skills in the use of explosives. Only experienced people trained in use of explosives or working under close supervision should work with explosives. All other miners should stay out of the way while the powder crew works unless assigned to the area.

Clearing the Blast Area

Clearing the blast area is very important. Unless the area is secured, other people may unknowingly walk into a life threatening situation from either the blast itself or the toxic fumes that follow the blast.

  1. The blasting crew will clear the area of all personnel, and then give a warning signal before setting of the round. Guards should be posted at all entrances to the area with specific instructions to keep everyone out. Guards should not leave their post even for a moment because someone could walk past without being seen. Guards must remain at their posts until specifically told to return to their regular work.
  2. Equipment should be moved clear of the blast area to prevent damage.
  3. Miners should stand clear of the blast area, such as behind equipment, to protect themselves from being hit by flyrock. Always give yourself enough room to stay clear.
An image of a warning sign outside of a mining area.
Photo by Kimon Berlin

Re-Entering the Blast Area

Before resumption of work, a supervisor or blaster will inspect the blast area for misfires and fumes. No one should enter this area past the guards until the all-clear signal is given by this person.

Reporting Undetonated or Misfired Explosives

Any miner who discovers an undetonated explosive near a magazine or along a haulageway, or a misfired explosive near their work area shall halt work, clear everyone out of the area and guard it, and notify a supervisor about the hazardous situation. Never attempt to move the explosive yourself because it may be very unstable and could go off in your hand.

Personal Protective Equipment

  • Hard hat
  • Safety Toed Shoes
  • Reflective Vest
  • Safety Glasses
  • Gloves
  • Hearing Protection

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AMIT 129: Lesson 6 Conveyor System

Overview

Conveyors  are common around surface mine yards and plants. They are an efficient way to move material, but can be very dangerous to those working around them. You may be asked to work around them: to clean up spillages, for example, or to perform routine maintenance on them. Mines have established procedures for working around belts.

Objectives

Upon completion of this lesson students will be able to:

  • Explain the conveyor system.
  • Define conveyor Start and Stop, Lock Out and Tag Out (LO/TO).
  • Explain conveyor tags.
  • Demonstrate how pull cords work.

Reading & Lecture

Conveyor Belts Safety

Following these safety rules will help keep you safe. Carelessness or lack of attention can result in your being pulled into the rollers or other moving parts, causing injury or death. Some common-sense safety practices are as follows:

  1. Tuck in loose clothing, or avoid wearing anything that is baggy enough to get caught by moving belts and rollers.
  2. Remove loose jewelry. Your mine may not allow jewelry at all, including necklaces, rings, or bracelets. Check with your safety training to see what the policy is.
  3. Do not remove guards from conveyor unless it is necessary to do the task assigned. Turn off the conveyor if possible, until your job is completed. Be sure to lock it out and tag it out. Replace guards immediately upon finishing and before restarting the conveyor.
  4. Be extremely cautious around rollers… you can get sucked in, and you will never win the battle against that equipment.

Conveyor belt shut off, lock out and tag out (LO/TO)

If you are asked to do maintenance on a conveyor, be sure it is turned off, locked out and tagged out. Notify everyone that you are turning off the conveyor, and be sure to check that it doesn’t have two sources of power. It is never a good idea to ride on a moving conveyor, so stay off of these pieces of equipment when they are running.

Before starting your task, make sure the conveyor is:

  • shut off (verify shut-off by checking the power meter)
  • locked out (keep the key to the lock in your pocket, always with you)
  • tagged out (put your name and the date on the tag and do not give your key to anyone else)

Be sure to:

  • never ask someone else to remove your lock, and do not take anyone else’s lock off of a power source – you could be killed if the equipment you are working on starts unexpectedly; and
  • know what the lock out/tag out devices are and where they are stored on your mine’s property.

After you have completed the lock out/tag out procedure, verify the power is off by pushing the start button. This will alert you if there is more than one power source to the conveyor.

Conveyors usually have “kill buttons” or “pull cords” on them to allow you to shut the power off immediately. You need to know where these are on every piece of equipment you are asked to work around so that in case of an emergency, you can shut down the conveyor. These devices are not a substitute for a LO/TO, however.

Diagram of an Austdac Pullkey ESS3 system
Diagram of an Austdac Pullkey ESS3 system

You may be asked to do maintenance on the upper end of the conveyor.

Make sure the anti-reversing mechanism on the head pulley is engaged to prevent the belt from rolling backward as you move up the conveyor. When working off the ground, at the top of the conveyor belt, for example, you must wear an approved fall protection harness. This is a belt with a lanyard that attaches you to the structure you are working on.

Your fall protection harness may have a self-retracting lanyard, or may have a fixed length lanyard. Either way, it does you no good if it isn’t attached to something that will hold your weight if you fall. Your safety trainer will provide additional training on the use of fall protection.

It is up to you to know when you should wear it, how to put it on properly, and how to check it for wear.

A photo of an inadequate pulley guard.

 

The picture above shows an inadequate conveyor tail pulley guard. The rear and top of the pulley are fully exposed providing access to moving machine parts.

The guard in the picture below covers the pinch point and the moving parts of the tail pulley. If properly maintained, this design can prove effective in preventing contact during work-related activities.

A diagram showing an effective pulley guard
[Conveyor image with enclosed pulley guard case]
An image showing the guard surrounding a tail pulley
[Elevated tail pulley image]
 

The figure above shows an elevated tail pulley. Because the underside of the pulley is accessible, it needs to be guarded. The guard may have openings large enough to allow fines to fall through, but not large enough to allow a miner to reach the moving machine parts.

Visible Signs of Bad Conveyor

  • Cut and or worn return idler brackets
  • Spillage in the load zone
  • Edge damage to the conveyor belt (See examples)
  • Hot marks on the sides of the head chute where the belt has been riding
  • Belt running off at the counter weight and tail pulleys

 

Conveyor Pogo Mine

Advantage of Keeping Your Conveyor Belts Clean

  • Increase your production
  • Eliminate downtime
  • Greatly reduce damage to conveyor belt edges & structures
  • Improve life of conveyor belt and conveyor components
  • Reduce spillage
  • Improve SAFETY

 

 

A covered conveyor
Image attribution: Brian M. Powell. This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license

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AMIT 129: Lesson 5 Hazard Recognition

Objectives

Upon completion of this lesson students will be able to:

  • Analyze accidents and contributing factors.
  • Identify causes of accidents.
  • Explain Miner’s responsibility.
  • Demonstrate proper handling of accidents.

Reading & Lecture

Analysis of Accidents and Contributing Factors

Definition of an Accident:

  1. Any unplanned and unanticipated event that results in personal injury and/or in property damage.
  2. An analysis of accidents must consider a number of contributing factors, which must at least include the accident type (falls, being struck by object), energy source (electricity, machinery), unsafe acts or conditions, nature of the injury, and the affected part or parts of the body.

Causes of Accidents

Basic causes of accidents may be one or more elements in the following lists.

  1. Management safety policy and decisions
    • Production and safety goals
    • Communications
    • Inspection procedures
    • Maintenance
    • Housekeeping
  2. Environmental factors
    • Weather
    • Dusts, gases and vapors
    • Noise
    • Illumination
  3. Personal factors
    • Safety motivation and awareness
    • Knowledge and training
    • Physical and mental state
    • Reaction time

 

Indirect Causes

Review this video introduction to unsafe acts and preventative safety methods.

Unsafe acts

  1. Operating equipment at excessive speeds
  2. Operating equipment without authorization or training
  3. Using equipment or tools improperly
  4. Using defective equipment
  5. Removing or damaging safety devices on equipment
  6. Not using personal protective equipment when appropriate
  7. Not warning others of hazardous conditions
  8. Failure to secure equipment and block tires
  9. Improper lifting, loading, or placement of equipment, tools, or supplies
  10. Servicing equipment in motion
  11. Horseplay
  12. Use of alcohol or drugs

Unsafe Conditions

  1. Sliding or falling material at bins, hoppers, and dump points
  2. Pressure lines and vessels
  3. Inadequate supports or guards
  4. Poor housekeeping
  5. Poor illumination
  6. Hazardous highwalls, spoil banks, and water pools
  7. Fire and explosion hazards
  8. Defective tools, equipment, or supplies
  9. Congestion of work place
  10. Inadequate warning systems
  11. Excessive noise
  12. Slippery or rough haulage and walkways
Highwall collapse on heavy equipment.
From the Department of Labor website, “On Wednesday, December 7, 2011, at approximately 7:30 a.m., a 49-year-old excavator operator, with 20 years of mining experience, was fatally injured when a highwall he was working near collapsed. The excavator was being used to load rock trucks. The operator’s cab was positioned on the highwall side when the accident occurred.”
An accident involving blind spots and heavy equipment
An accident at the Anglo Coal Mine, caused by a blind spot while operating heavy equipment.
The results of a falling material accident
From the Department of Labor website, “On August 3, 2015, a 64-year old miner with 44 weeks experience was killed at a sand and gravel mine. The victim was operating a front-end loader, loading trucks from a stockpile, when he exited the loader. While outside the loader, the approximate 35-foot high stockpile slope failed and engulfed the victim between the stockpile and the loader.”

Direct Causes

  1. Unplanned release of energy and/or hazardous material such as falls of rock or materials, failing brakes, or removal of air hose without bleeding the line

Distinction between health and safety concerns in the mine

  1. Health refers to proper functioning of the body
    • Health is affected by substance which interfere with normal functioning.
    • Health problems, while slow in occurring, may be permanently disabling
  2. Safety refers to avoiding accidents by following safe work procedures and recognizing and correcting unsafe conditions.

Miner’s responsibility

  1. Reporting hazards
  2. Tagging unsafe equipment
  3. Eliminating known hazards
  4. Warning others
  5. Avoiding areas of hazards

Common Types of Accidents

Most Common Types of Accidents in Metal/Nonmetal Underground Mines

Handling materials is a common activity related to accidents (lifting, puffing, pushing or shoveling packaged or loose material).

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Frequency of Occurrence

Of all accidents reported in 1979 for underground mines, 31% occurred during handling of materials.

Accident Characteristics

Of all accidents in underground mines involving materials handling, 62% resulted in lost work days for non-fatally injured miners. The average severity of these accidents was lost time ranging from 12 to 164 days.

Most frequent parts of body injured in accidents

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Most frequent nature of injury

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These accidents may often be avoided by using correct procedures for handing materials.

  • Use proper lifting, lifting with the legs rather than the back.
  • Wear gloves.
  • Do not allow your vision to be obscured by the load and be careful when passing through entrances.
  • Do not attempt to carry a load which is too heavy, and coordinate your moves with those assisting you.
  • Be careful of sharp edges or protruding sides of the materials you are carrying.
  • When setting materials down, make sure you have sufficient clearance from your toes.

Accidents Caused By Powered Haulage Activities

Powered haulage activities are another source of accidents (conveyors, front-end loaders, haulage trucks, locomotives and railroad cars, and personnel conveyances).

Frequency of occurrence

Of all accidents reported in 1979 for underground mines, 8% occurred around powered haulage.

Accident characteristics

Of all accidents in underground mines involving powered haulage, 74% resulted in lost work days for non-fatally injured miners. The average severity of these accidents was lost time ranging from 30-210 days.

Most frequent parts of body injured in accidents

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Most frequent nature of injury

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Some of the sorts of haulage accidents which occur are as follows:

  • Collisions with other vehicles or stationary objects
  • Being struck, run over by or squeezed between vehicles
  • Striking arms, legs, or other body parts against protruding objects while     riding in mine transportation
  • Slipping or falling while mounting vehicle

Haulage accidents may be reduced by using the rules as follows:

  1. Never exceed the vehicle’s capabilities for speed, stop-ping, and turning.
  2. When on foot watch out for all vehicles and let operators know you are near.
  3. Never get on or off of moving vehicles of any kind.
  4. Keep limbs and head within the riding area.
  5. Make frequent inspections of vehicle’s brakes, lights, steering, and other devices related to safety.
  6. Don’t work on moving conveyor belts or attempt to cross or mount them.
  7. Don’t wear loose clothing or long hair around moving conveyor belts or machinery which has exposed moving parts.
  8. When shoveling onto a moving belt, always shovel in the direct the belt is moving.

Accidents Caused By Use of Machinery

Another major source of accidents is the use of machinery (drills, slushers, power shovels, and compressors).

Frequency of occurrence

Of all accidents reported in 1979 for underground mines, 17% occurred around machinery.

Accident characteristics

Of all accidents in underground mines involving machinery, 64% resulted in lost work days for non-fatally injured miners. The average severity of these accidents was lost time ranging from 18 to 194 days.

Most frequent parts of body injured in accidents

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Most frequent nature of injury

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The sorts of accidents which occur are as follows:

  • Being caught between a machine and the highwall during a slide.
  • Being struck by a moving boom or bucket or blade
  • Being struck or crushed by falling or overturning equipment.
  • Being struck by flying objects.

Many accidents of this nature can be avoided by following safe work procedures.

  • When working near equipment in operation, be sure the operator knows you are there.
  • Avoid the area included in the circle of movement of booms and loaders. Never walk under raised equipment.
  • Never leave equipment unattended in raised position.
  • Be sure equipment is securely blocked before attempting any repair or maintenance with it in raised position.
  • Never attempt to defeat or override the safety devices built into equipment.

Injuries form Slips and Falls

Another source of accidents is slips and falls (while getting on or off machinery and haulage equipment which is not moving, and while servicing or repairing equipment or machinery).

Frequency of occurrence

Of all accidents in 1979 for underground mines, 13% resulted from slips and falls.

Accident characteristics

Of all accidents in underground mines resulting from slips and falls, 73% resulted in lost work days for non-fatally injured miners. The average severity of these accidents was lost time ranging from 21 to 210 days.

Most frequent parts of body injured in accidents

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Most frequent nature of injury

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Some rules which will prevent slips and falls are as follows:

  1. Wear proper footwear.
  2. Always watch where you are going. Don’t allow material being carried to block your visibility.
  3. Use both hands when climbing up or down a ladder. Never jump from rung to rung or try to slide down the ladder.
  4. Clean up any spills that might cause someone to slip.
  5. Never lean over equipment without stable footing.
  6. Use a safety belt to catch any fall from a high place, or when working in a hole or trench.

Injuries From Use of Hand Tools

An additional major source of accidents is the use of hand tools (non-power assisted tools)

Frequency of occurrence

Of all accidents in 1979 for underground mines, 11% resulted from use of hand tools.

Accident characteristics

Of all accidents in underground mines resulting from use of hand tools, 45% resulted in lost work days for non-fatally injured miners. The average severity of these accidents was lost time ranging from 11 to 125 days.

Most frequent parts of body injured in accidents

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Most frequent nature of injury

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The following are procedures which will help in avoiding these accidents.

  • Use the right tool for the job.
  • Keep tools in their place when they are not being used. Don’t leave them around as hazards to safety.
  • Be sure you have clearance from other workers and machinery when using hammers and sledges.
  • Always wear safety glasses to protect your eyes from flying material.
  • Follow recommended safety procedures in the use of special tools and equipment.

Injuries From Falls to Back or Sides

The final major source of accidents is falls of the back or sides. This includes falls while barring down or placing props, as well as pressure bumps and bursts. This does not include accidents due to equipment gouging the rock.

Frequency of occurrence

Of all accidents in 1979 for underground mines, 10% resulted from falls of the back or sides.

Accident characteristics

Of all accidents in underground mines resulting from falls of the back or sides, 65% resulted in lost work days for non-fatally injured miners. The average severity of these accidents was lost time ranging from 12 to 600 days.

Most frequent parts of body injured in accidents

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Most frequent nature of injury

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These accidents may often be avoided by observing some of the following safety rules.

  • While barring down always follow safe procedures and keep a path for escape open. When scaling, always wear safety glasses and work under supported roof.
  • If you suspect weak rock, report it to supervision.
  • Test the rock periodically with a hammer to assess its soundness.
  • Never violate the mine’s roof control plan.
  • Look for stress cracks or rocks protruding from the back or sides.
  • Look for formerly dry areas that suddenly become wet.
  • Look for the falling of small chips that might signal larger falls.
  • Look for rock bolts showing signs of stress.
  • Never assume someone else has made tests in the area.

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AMIT 129: Lesson 1 Intro

Overview

Objectives

After completion of this lesson, students will:

  • Understand definitions of open pit and underground mine
  • Learn Mining methods
  • Learn Mining equipment’s
  • Understand Ground control
  • Recognize Mining hazard
  • Know Personal Protective Equipment

Vocabulary

Familiarize yourself with vocabulary introduced in this lesson.

Adit: An adit is a horizontal or nearly horizontal entrance to a mine.
Back: The back is the roof or overhead surface of an underground excavation.
Chute: A chute is a loading arrangement that utilizes gravity flow to move material from a higher level to a lower level.
Cone: A cone is a funnel-shaped excavation located at the top of a raise, and it is used to collect rock from the area above.
Crosscut: A crosscut is a horizontal or nearly horizontal underground opening that is driven to intersect an ore body. Dip: The dip is the angle at which an ore deposit is inclined from the horizontal.
Drawpoint: A drawpoint is a place where ore can be loaded and removed. A drawpoint is located beneath the stopping area, and gravity flow is used to transfer the ore to the loading place.
Drift: A drift is a horizontal or nearly horizontal underground opening.
Finger Raise: A finger raise is used for transferring ore. The usual arrangement is as a system of several raises that branch together to the same delivery point.
Footwall: The footwall is the wall or rock under the ore deposit (compare dip).
Grizzly: A grizzly is an arrangement that prevents oversize rock from entering an ore transfer system. A grizzly usually consists of a steel grating for coarse screening or scalping.
Hanging Wall: The hanging wall is the wall or rock above an ore deposit (compare dip).
Level: A level is a system of horizontal underground workings that are connected to the shaft. A level forms the basis for excavation of the ore above or below.
Manway: A manway is an underground opening that is intended for personnel access and communication. Ore: An ore is a mineral deposit that can be worked at a profit under existing economic conditions.
Orepass: An orepass is a vertical or inclined underground opening through which the ore is transferred.
Prospect: A. prospect is a mineral deposit for which the economic value has not yet been proven.

Reading

Surface mining is the predominant exploitation procedure worldwide. Almost all metallic ores (98%), about 97% of the nonmetallic ores and 61% of the coal in the Unites States are mined using surface methods. And most of these are mined by open pit or open cast methods.

In open pit mining, a mechanical extraction method, a thick deposit is generally mined in benches or steps, although thin deposits may require only a single bench or face. Open pit is usually employed to exploit a near-surface deposit or one that has a low stripping ratio.

Underground mining  is a method which divides into unsupported, supported and caving- are differentiated by the type of wall and roof supports, the configuration and size of production openings, and the direction in which mining operations progress. The unsupported methods of mining are used to extract mineral deposits that are roughly tabular (plus flat or steeply dipping) and are generally associated with strong ore and surrounding rock. Supported mining methods are often used in mines with weak rock structure. Caving methods are varied and versatile and involve caving the ore and/or the overlying rock.

Mining Method

Reaching the Ore Body Extracting         Ore Ground
Control
Haulage Processing Facilities
Shaft

Slope or inline

Outcrop or drift

Portal entries

Room and pillar

Stopes

Raises

Block caving

Timber

Rock bolts and split sets

Concrete and shotcrete

Rubber tired

Track

Grizzly and crusher

Mills

Mining Hazards and Accident Prevention

Unsafe Conditions Unsafe Acts
Ground hazards

Electrical hazards

Gas hazards

Explosive and fuel hazards

Taking risks in operating or maintaining equipment

Bending and lifting

Slips and falls

Mining Equipment and Their Functions

Equipment for reaching the ore body Equipment for extracting ore Equipment for ground control Equipment for haulage
Hoist

Boss buggy

Man trip

Walking

Stoper drill

Jack-leg drill

Jumbos

Muckers

Stoper drill

Jack-leg drill

Jumbo drill

Rock bolts and split sets

Timbers

LHD

Slusher

Muckers

Youngbuggies

Locomotives and ore cars

Company Safety Policy and Rule Book

  1. Management commitment to safety
  2. Safety rules

Ground Control – Underground Supports

  • Provide a safe workplace by supporting the roof and rib to prevent unintentional rock falls.
    Depending on:

    • geological conditions
    • mining methods
    • miners experience
  • Commonly used ground control methods:
    • Timbering
    • Rock/roof bolts
    • Split sets
    • Steel props
    • Concrete lining or shotcrete

Mine Hazards and Accident Prevention

Unsafe condition can cause accidents. These are condition not under the direct control of miners. However, good accident prevention procedures, such as workplace inspection and equipment maintenance, can minimize unsafe conditions. The following are common unsafe conditions.

  1. Ground hazards include falls or back or rib.
  2. Electrical hazards include faulty insulation, splices and grounding.
  3. Gas hazards include fumes from diesel-powered equipment, fires, batteries and blasting.
  4. Hazards will explosives and fuels are always present but are minimized through safe work practices. Transportation of explosives and diesel fuel require additional care.

Unsafe acts are usually the result of taking unnecessary risks and/or trying to take short cuts in proven safe work procedures. Your motivation to work safely will reduce the likelihood for accidents and injury by minimizing unsafe acts.

  1. Taking risks in operation or maintaining equipment means that it is only a matter of time before an accident occurs. Always drive safely. Use your seat belt. Do not give rides in buckets or other areas not intended for transportation.
  2. Much of a miner’s work involves bending and lifting. Always follow safe procedures by bending your knees and using them, rather than your back, to lift. If the load is too heavy or awkward get help. Avoid lifting while your body is twisted or turned. Remember to use tall enough ladders, reach safely, and avoid lifting heavy items overhead.
  3. Wet or oily surfaces, protruding objects, or inattention can cause slips and falls.

A Culture of Safety in a Mining Context

 

Lifting Heavy Objects

A diagram demonstrating how to lift properly
By Unknown or not provided – U.S. National Archives and Records Administration, Public Domain, https://commons.wikimedia.org/w/index.php?curid=17220893

 

  • If the load is too heavy, GET HELP.
  • When using a two-person carry, both carriers face in direction of travel.
  • When lifting in confined areas on hands and knees, lift object with one hand balance with the other.

OSHA Back Safety

 

Personal Protective Equipment

Personal protective equipment is equipment worn to minimize exposure to serious workplace injuries and illnesses. These injuries and illnesses may result from contact with chemical, radiological, physical, electrical, mechanical, or other workplace hazards.

Personal protective equipment is always required on a mine site. It is your responsibility to know how to use it properly, and to wear it whenever you are working.

Some PPE’s are common to all mines, while some may be site-specific for your mine. These include:

  •   safety glasses for protection from rocks, dust and other flying debris;
  •    hard hats;
  •    steel toed boots;
  •    hearing protection;
  •    respirators

PPE Chart

PPE Basics

PPE Overview from OSHAGeneral Respirator Safety from OSHA

 

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