Pennsylvania Code
Title 34 - LABOR AND INDUSTRY
Part I - Department of Labor and Industry
Chapter 43 - TUNNEL CONSTRUCTION AND COMPRESSED AIR WORK
Subchapter A - TUNNEL CONSTRUCTION AND WORK IN COMPRESSED AIR
TUNNEL CONSTRUCTION
Section 43.26 - Blasting

(a) There shall be one blaster in charge of blasting in each section.

(b) No one who has not received a permit from the Department shall be employed as a blaster anywhere within the jurisdiction of the Department.

(c) The explosives used shall be such as to cause the least amount of injurious gases.

(d) No blaster shall attempt to use any frozen dynamite. No quantity greater than is sufficient for daily use shall be artificially thawed at one time. Only approved methods of thawing shall be permitted.

(e) Except in cases of instantaneous blasting by electricity, a blaster shall count the number of shots exploding when he fires a round of holes. If there are any misfires, he shall remain until the misfires have been exploded or holes made safe.

(f) If a fuse is used, misfires shall not be approached, even for purposes of inspection, until three hours have elapsed. If electric blasting caps are used, misfires shall not be approached, even for purposes of inspection, until 15 minutes have elapsed.

(g) Whenever feasible, a charge that has failed to explode shall be exploded by inserting a new primer in the hold on the old charge and detonating the primer.

(h) The blaster shall use only hardwood rods for tamping. He shall not tamp or load any hole with a metal bar, nor shall the wooden rod have any metal parts.

(i) Firing shall be done by safety fuse or approved battery or from an electric current of not over 250 volts, if an approved switch is used. Other methods of firing may be permitted upon approval by the Department.

(j) When firing by electricity from power or lighting wires in any tunnel, an approved switch shall be furnished with the lever down when in the "off" position. The switch shall be fixed in a locked box, to which no person shall have access except the blaster. There shall be flexible leads of connecting wires at least five feet in length with one end attached to the incoming lines and the other end provided with plugs that may be connected to the switch on the inside shot-firing circuit when firing and that shall at all times be connected to an effective ground. After blasting, the switch lever shall be pulled out, the wires disconnected and the box locked before any person shall be allowed to return, and shall remain locked until again ready to blast. Blasting wires shall be laid on the opposite side of the tunnel from the lighting and power wires.

(k) Before the loading of holes, all powerlines and electric light wires shall be disconnected at a point outside the blasting switch. After explosives are taken in, preparatory to blasting, no current by grounding of power or bonded rails shall be allowed beyond the blasting switch. Under no circumstances shall ground current be used for exploding blasts.

(l) The blaster shall cause a sufficient warning to be sounded and shall be responsible to see that all persons retreat to safe shelter before he sets off the blast, and shall also see that no one returns until he reports it safe. He shall report to the tunnel foreman and furnish names of all persons refusing to obey his caution.

(m) No person shall be allowed to deepen holes that have previously contained explosives.

(n) All wires in broken rock shall be carefully traced and a search made for unexploded cartridges.

(o) Whenever blasting is done at points liable to break through to where other men are at work, the foreman or person in charge shall, before any holes are loaded, give warning of danger to all persons working where the blasts may break through, and he shall not allow any holes to be charged until warning is acknowledged and the men are removed.

(p) When testing circuits through charged holes, blasters shall use sufficient leading wires to be at a safe distance and shall use only approved types of galvanometers. No tests of circuits in charged holes shall be made until men are removed to a safe distance.

(q) No blasts shall be fired with fuse in vertical or steep shafts.

(r) In shaft sinking where the electric current is used for firing, a separate switch not controlling any electric lights shall be used for blasting. Proper safeguards similar to those in tunnels shall be followed in order to insure against premature firing.