513 EM 385-1-1 Chapters 23-29

Sections

29-8. General Requirements.

Wiring Instructions

Electric initiation systems must be wired according to the Master Blasting Plan and manufacturer’s recommendations.

Firing Procedures

Before each shot, warn everyone in the blast area, post a flag person at all access points, and move drill boats and vessels to a safe distance.
Use safety signals (warning, blast, and all clear signals) with a compressed air whistle, horn, or equivalent, and ensure they are audible throughout the blast area.
The Blaster-in-Charge must handle lead line connections, fire the shot, and disconnect the leading wires from the power source immediately after firing.

Post-Blast Procedures

After each blast, disconnect the firing line, test the atmosphere, and ventilate confined spaces as necessary.
Allow only the Blaster-in-Charge to return to the blast area until the "all clear" signal is given, and then scale down loose debris.
Handle misfires under the direction of the Blaster-in-Charge following the Master Blasting Plan and maintain safety protocols during the process.

Underwater Blasting Guidelines

All operations must be conducted by a Blaster, using water-resistant materials and avoiding dissimilar metals for loading tubes and casings.
Display blasting flags and ensure the proper setup and alignment of drill holes to avoid intersection, using vertical holes and verifying plumbness.

29-9. Figures and Tables.

Not Applicable.

29-10. Checklists and Forms.

Not Applicable.

Knowledge Check Choose the best answer for the question.

29-9. During blasting operations, who must handle lead line connections, fire the shot, and disconnect the leading wires from the power source immediately after firing?

The Blaster-in-Charge

The Blaster

The Blasting Supervisor

The Master Blaster

You forgot to answer the question!

EM 385-1-1 Paragraph 29-8 (l.–o.).

29-8. General Requirements. (l.–o.).

l.  Wiring. Wire electric initiation systems according to the Master Blasting Plan and the manufacturer’s recommendations.  (29-8.l)

m.  Firing. (29-8.m)

(1)  Prior to firing each shot, warn all persons in the blast area of the blast and order to a safe distance from the blast site.  Do not fire blasts until it is certain that every person has retreated to a safe distance and no one remains in a dangerous location.

(2)  Prior to firing each shot, a flag person must be posted at all access points of the blast area to prevent access.

(3)  Prior to firing each shot, drill boats and other vessels must be moved to a safe distance from the blast area.

(a)  Prior to and while the drill boat or vessel is being moved from the blast area, sound off a series of short signals by horn or whistle like the usual navigation warning signals.

(b)  Do not fire any blast while any vessel under way is closer than 1,500 feet (457.2 m) to the underwater blasting area.  Notify those onboard vessels or craft moored or anchored within 1,500 feet (457.2 m) before each blast is fired.

(c)  Do not fire any blast closer than 250 feet (76.2 m) to a boat or vessel containing an explosive magazine.  Personnel engaged in drilling operations on another drill boat within 500 feet (152.4 m) must leave the drill frames for cover if any holes have been loaded.

(d)  Do not fire any blast while any swimming or diving is in progress near the blasting area.

(e)  Whenever a drill boat is moved from the drilling location, fire all loaded under water holes.

(4)  Safety Signals.

(a)  All blasting operations must use the following safety signals:

(a-1)  WARNING SIGNAL.  A one-minute series of long audible signals made 5 minutes prior to the shot.

(a-2)  BLAST SIGNAL.  A series of short audible signals made 1 minute prior to the shot.

(a-3)  ALL CLEAR SIGNAL.  A prolonged audible signal following the inspection of each blast site.

(b)  Make the safety signals using a compressed air whistle, a horn, or equivalent means.  The signals must be clearly audible at the most distant point in the blast area. Do not use the boat whistle on a drill boat as a safety signal.

(d)  Train individuals so they are familiar with the safety signals and instructions.

(5)  The Blaster-in-Charge will make the lead line connections and fire the shot.
    Make all connections from the borehole back to the source of firing. Do not connect the lead line to the blasting machine or other source of energy until the charge is to be fired.

(6)  After firing an electric blast, immediately disconnect the leading wires from the power source and shunted.

(7)  When firing a circuit of electric blasting caps, take care to ensure that an adequate quantity of delivered current is available according to the manufacturer's instructions.

n.  Post-Blast Procedures.  (29-8.n)

(1)  Immediately after each blast has been fired, disconnect the firing line from the blasting machine or power source and lock open all power switches.  Test the atmosphere in each confined space and ventilate, as necessary.

(2)  Do not permit anyone other than the Blaster-in-Charge to return to the blast area until the "all clear" signal is given.

(3)  Scale down loose pieces of rock and other debris from the sides of the face of the blast site and make the blast area safe before proceeding with other work.

(4)  Misfires.

(a)  Handle misfires under the direction of the Blaster-in-Charge according to the procedures in the established Master Blasting Plan.  The Blaster-in-Charge will determine the safest method for handling the hazards of misfires (some misfires may require consultation with the supplier or manufacturer of the explosive material).

(b)  Do not perform other work within the misfired area except work that is necessary to remove the misfire hazard.  Only those employees necessary to do the work may remain in the misfire area.

(c)  Do not drill, dig, or pick near the misfire holes until they have been detonated or the Blaster-in-Charge has approved that work can proceed.

(d)  Depending on the experience and ability of the Blaster-in-Charge, a secondary/dual initiation system to prevent misfires should be considered.

(e)  When a misfire is declared, the Blaster must wait 30 minutes (cap and fuse
    1-hour) before inspecting the site and provide proper safeguards for excluding all employees, except those necessary to do the work, from the blast area as defined in the Master Blasting Plan. The Blaster must establish the limits of the misfired area around the misfire according to the site-specific Master Blasting Plan.

o.  Underwater Blasting.  (29-8.o)

(1)  A Blaster must conduct all blasting operations.  No shot will be fired without their approval.

(2)  Do not use loading tubes and casings of dissimilar metals because of possible electric transient currents from galvanic action of the metals and water.

(3)  Use only water-resistant blasting caps and detonating cords for all marine blasting.  Load through a rigid non-sparking loading tube.

(4)  Display blasting flags.

(5)  When more than one hole is loaded, anchor and float a steel shot line over the row of loaded holes.  Tie the detonation down line from each loaded hole to the steel line and tie the loose end to the detonation trunk line.

(6)  Include in the Master Blasting Plan the means and methods by which blast holes will be kept from intersecting when drilling near or adjacent to a loaded hole.

(a)  Drill only vertical holes.

(b)  If a casing, auger, or drill mast is used, it must be vertically plumbed at set up, when drill steel is added or every 5 feet (1.5 m) whichever is shorter, and upon completion.  The casing, auger, or drill mast must extend from the barge and be firmly seated.

(d)  Abandon any hole that is out of plumb by more than three degrees from vertical and adjust adjacent hole spacing to prevent intersecting other holes.

(e)  Halt drilling to check alignment with an inclinometer or approved device every 5 feet  (1.5 m) of hole depth.