vtca-msha safety seminar · 2017. 4. 13. · blast shelter signalling. blast area safety-clearing...

VTCA Safety SeminarsBlasting Safety

Blasting/Explosives Safety

� Definitions

� Blast Site Safety

� Pre Blast Concerns

� Blast Area

� Post Blast Exams

� Misfires

� Flyrock

State/Local Blasting Requirements

� Note: State and local blasting requirements may be more strict than the federal requirements.

� Some states require a new miner to attend their training program prior to entry into a mine.

� Virginia requires GMM Training

Blasting/Explosives SafetyDefinitions Surface Metal/Nonmetal

� Blast Site, Part 56 – The area where explosive materials are handled during loading. This includes the 50’perimeter around the loaded holes in all directions. 50’ requirement can be reduced to 30’ if perimeter is demarcated with a barrier.

Blasting/Explosives SafetyDefinitions Underground Metal/Nonmetal

� Blast Site, Part 57 – The area where explosive materials are handled during loading. This includes the 50’perimeter around the loaded holes in all directions. 50’ requirement can be reduced to 30’ if perimeter is demarcated with a barrier. 15’ or more of solid pillar or broken rock can be substituted for the 50’ distance.

Blasting/Explosives SafetyDefinitions Surface & Underground M/NM

� Blast Area, Part 56 & 57– The area where concussion, flying material, or gases from an explosion may cause injury to person.

VTCA Safety Seminars

� Blast Site Safety� 30 CFR 56/57.6306(a)

Loading, Blasting and Security

� “When explosive materials or initiating products are brought to the blast site, the blast site shall be attended; barricaded or posted with warning signs, such as “DANGER,” or “Keep Out;” or “flagged against unauthorized entry”


� Control of Blasting Operations 56/57.6300 (a)

� “only persons trained and experienced in the handling and use of explosive material shall direct blasting operations and related activities”

� “trainees and inexperienced persons shall work only in the presence of persons trained and experienced in the handling and use of explosive materials”

Blast Site Safety-Pre Blast Hazard Assessment

� Inspect the work area/blast site to be sure this area is safe to work at.

� Inspect the face for proper burden.

� Inspect the highwall edge for overhangs and undercuts.

Blast Site Safety - Safety Meeting

� Conduct pre-blast safety meeting with the blast crew. Document the meeting

� Review:� Blast plan

� Any hazards in the area

� Loading procedures

� Aid in the movement of equipment

� Use of Wheel Chocks

� Use of Personal Protective Equipment

� Blast signals

� Guarding

Blast Site Safety-Fall Hazard Zone

– Visual Warnings • Signs or Tape

• Cones or Boulders

• Paint or Chalk

– Physical Barriers• Berms or Boulders

• Handrails

• Fencing

• Cables

– Belt or Harness and Lanyard

– Buddy System

Blast Site Safety - Boreholes

� Measure burden, spacing, and hole depth for proper measurements prior to loading.

Blasting Safety - Drill Logs

� Safety:� Communication with

driller and blaster to reduce flyrock.

� Custom load holes according to changing rock conditions.

� Caves/Voids.

� Mud seams

� Amount of overburden

Blasting Safety-Drill Logs

� Performance:� Fragmentation with low

vibration and air blast.

� # holes and depth.

� Blast hole deviation.

� Actual burden and spacing.

� Any changes to layout.



� 30 CFR 56/57.6306(c) Loading, Blasting and Security

� “ Once loading begins, the ONLY activities permitted within the blast site shall be those activities directly related to the blasting operation…”



� 30 CFR 56/57.6306(c) Loading, Blasting and Security

� “ …and the activities of surveying, stemming, sampling of geology, and reopening of holes, PROVIDED that reasonable care is exercised.”

VTCA Safety SeminarsBlast Site Safety/ Security

50 feet

Charged or Loaded Holes

Uncharged orUnloaded Hole

50 feet

50

feet

50

feet

9 Holes2 Loaded7 Unloaded


� Blast Site Safety (Shot Loaded)

Loaded Shot

50 ft Perimeter

New DrillingPermitted

NoDrilling

PermittedInside50 ft

Perimeter

Blast Site Safety - Loading

� When Boosters and Detonators are laid out they should be separated on the ground.


� Primers shall only be made up at the time each hole is loaded.

� Do not assemble primers ahead of time and leave on the surface.

� Pre Blast Concern� Premature

Detonation:� Activities

� Loading

� Hookup

� Initiation by

� Mechanical

� Electrical

� Chemical

� Thermal


� Pre Blast Concern� Mechanical Premature

Detonation� Tamping on a

primer

� Dropping of a large diameter cartridge on a primer

� Running over a primer lying on the bench

� Drilling into a hole containing an explosive material

� WHAT ELSE???


� 30 CFR 56/57.6306(b) Loading, Blasting and Security

� “Vehicles and equipment shall not be driven over explosive material or initiating systems in a manner which could contact the material or system, or create other hazards”


Blast Site Safety-Vehicles

� When out of the cab of the vehicle, the wheels of each vehicle shall be chocked.

� This includes all rubber tire mobile equipment.


� Rigid cartridges of explosives 4” in diameter or larger shall not be dropped directly on the primer.

� Protect the primer from tamping.



� Pre Blast Concern

� Electrical Premature Detonation

� RF Energy

� Power Lines

� Lightning

Blast Site Safety-Loading

� Electrical Storms, Use the 30 Second Rule

� If the time between seeing lightning and hearing thunder is less than thirty seconds, you are in danger.

� You can turn on a AM radio to detect if any lightning is in the area. Listen for static.

� Lightning detectors can be used.


� Electrical Storms� Surface-During the progress

and approach of an electrical storm, all blasting operations shall cease.

� Underground-Electrical blasting operations capable of being initiated by lightning shall be suspended and miners withdrawn from the blast area until safe to return.

� All miners shall be evacuated from the blast area until the storm has passed.

Bad Weather


� Electric Detonators� Check Continuity of each

detonator prior to stemming and circuit resistance prior to connection to the power source.

� Only use approved BLASTER’s Galvanometer and BLASTER’smultimeter to check electric detonators and circuits.


� E*Star Electronic Detonators:

“Internal shunting by protective devises contained in the E*Star detonator replaces the need for an exterior mechanical means of shunting.”

Blast Site Safety- Loading

� Non-Electric Detonators

� Have a second qualified person verify all non-electric connections.


� Lead Detonator Connection

� Once the Lead detonator is connected, the lead lines/wires must be manuallyunreeled.


� ELEMENTS OF BLAST AREA SECURITY

� CLEARING

� COMMUNICATING

� GUARDING

� CONTROLLING

� BLAST SHELTER

� SIGNALLING

Blast Area Safety-Clearing

� 30 CFR 56/57.630(f)

� Ample time shall be given to allow all miners to be evacuated from the blast area.

Blast Area Safety-Clearing

� There shall be no connection to the power source or attaching an initiating device to the blast until all miners have left the blast area.


BLAST AREA SAFETY� Guarding

� Assignments

� Locations

� Safety Equipment

� Protection against flyrock

� Orders

� Duties

� Release of Duties


BLAST AREA SAFETY� Communicating

� Guard/Blaster Communication Devices

� Guard Communication Instructions

� Notice of Breach

� Understanding of the Blasting Signals


BLAST AREA SAFETY

� 30 CFR 56/57.6306(f)

� (3) “ All access routes to the blast area shall be GUARDED, or barricaded to prevent the passage of persons or vehicles.”

VTCA Safety SeminarsGuarding and Guard Points

2-Lane Public Highway

Blast Site

Point B

Point D Point EHighway

Control PointHighway

Control Point

Mine Haul Road-Down Ramp

Mine Haul Road-Up Ramp

Point C

Point A

RampControlPoint

RampControlPoint

Blast Area Safety-Clearing the Blast Area

� The blaster shall verify the blast area is clear.

� Double check to be sure all miners and equipment are clear.

� Are access points guarded?

Blast Area Safety-Blast Shelter

� The blaster, and all other miners in the blast area, shall be protected by a blasting shelter.

� What is a proper blasting shelter?

Pictur ?

Blast Area Safety-Blast Shelter

� If you have any question about what type of blasting shelter to use or what is proper cover, ASK BEFORE YOU USE IT.

VTCA Safety SeminarsBest Location for Shelter?

Upper Bench

SHOT

Blaster Protective Shelter-Discussion Locations

PIT FLOOR

Two Bench Mine (BH= 50 ft)

Face

Lower Bench A

D

E

BC

F

G

HI

Blast Area Safety

Wireless Remote Firing Device


BLAST AREA SAFETY

� Blasting Signals

� Audible

� Time Schedule

� Posted


BLAST AREA SAFETY� Blasting Signals

� PRE BLAST� Audible

� First Warning

� Time before detonation?

� 3 min. prior

� Signal Type

� 1 min. siren

� 30 sec. Silence

� 1 min. siren

� 30 sec. BLAST!


� Blast Area (MSHA)� Gases ?

� Carbon Monoxide (CO)

� Colorless/Odorless

� Cause???

� Oxides of Nitrogen (Nox)

� Yellow-Brown-Red?

� Cause???

Blast Area Safety-Post Blast/ Fumes

� Fumes are Toxic.

� Fumes shall be allowed to dissipate prior to re-entry into the blast area.

Blast Area Safety-Post Blast Exam

� A Post Blast Exam shall be performed addressing potential blasting hazards.

� This exam shall be conducted prior to work being able to resume in the blast area.

BLAST AREA SAFETY

� Blasting Signals

� POSTBLAST

� Audible

� Means no Misfires, miners may return to the work area

� Signal Type (EXAMPLE)

� 30 seconds all clear

Blast Area Safety-Post Blast

Blast Area Safety-Post Blast “All Clear”

� An “All Clear” Signal shall be given once the post blast exam has been completed and there are no dangers present.

Blast Area Safety-Misfire Procedures

� What is a Misfire?

� The complete or partial failure of explosives to detonate as planned.


� Cause for Misfires?� Human Error

� Hurrying

� Holes not connected

� Not measuring column rise

� Product Failure� Age

� Uncoupling

� Defective

� Wrong Application

� Not used according to manufacturer’s instructions.

� Anything Else?

Blast Site Safety-Is it a Misfire?

� If you push the button on the firing device and the shot does not detonate, is this a misfire?

� Answer: YES. Misfire procedures must be followed.

Blast Area Safety-Is it a Misfire?

� If you forget to connect the last two holes into the blast round, is this a misfire?

� YES. Misfire procedures must be followed.


� What are the misfire procedures? Before entering the blast area:

� The power source must be disconnected from the blast round.

� The firing line must be shunted, if using electric.


� What are the misfire procedures?

30 CFR § 56.6310

Misfire waiting period.When a misfire is suspected, persons shall not enter the blast area--

(a) For 30 minutes if safety fuse and blasting caps are used; or

(b) For 15 minutes if any other type detonators are used.


� What are the misfire procedures? � Defer to State Regulation

� Clear area for 15 min.

� BIC, Pit Foreman, or Plant Manager contact:

� Discuss proper procedures to approach/remove misfire


� What are the misfire procedures? � When a misfire cannot be

disposed of safely, each approach to the misfire area shall be posted/blocked to prohibit entry into this area.

� Only work necessary to remove the misfire hazards shall be permitted in the area.


� Flyrock (IME SLP #12)

� Definition

� “Rocks propelled by the force of an explosion beyond the blast area.”

FLYROCK

� Blast Area Definition (MSHA)� Flying Material?

� Rock

� Shot Rock

� Rock on the surface of a Shot

� Stemming Ejection

� Earth

� Overburden

� Mud Seams

� Ice

� Man-made things such as steel, concrete, etc

This piece of rock was flyrock

� Major Causes

� DELAYING

� ROCK MOVEMENT RELIEF

� OVERLOADING

� MISFIRES

FLYROCK

� Flyrock

� OVERLOADING

� Insufficient Stemming

� Prevention ???

FLYROCK

� Flyrock

� OVERLOADING

� Insufficient Stemming

� Prevention

� Adequate Stemming for Charge Diameter and Shot Relief

FLYROCK

� Flyrock

� OVERLOADING

� Insufficient Burden

� Prevention

� Adequate Burden for Charge Diameter

� Decoupled Charge

� Don’t Charge or Charge only bottom

FLYROCK

VTCA Safety SeminarsBlasting Safety

Questions

vtca-msha safety seminar · 2017. 4. 13. · blast shelter signalling. blast area safety-clearing...

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