BLASTING WITH NITRO-GLYCERIN AT THE HOOSAC TUNNEL
From the North Adams (Mass.) Transcript
Monday, March 2, A.D. 1868, ushered in a snowing, gusty day; the wind, during the proceeding night, had been urging puffs of snow, dry and crystalline, through every cranny of the mountain shanty, before whose soapstone stove I had been warming my rheumatic limbs; and, since travel seemed impracticable, I made a virtue of necessity, and accepted an invitation from my host to descend the west shaft of the Hoosac Tunnel, where the temperature, 60 deg. F., would at least be more agreeable than on the mountain side, where their thermometer was then 6 deg. below zero.
So donning a miner’s suit, rubber boots, Cape Ann oilskin jacket and south caster, we stalked through the deep drifts of snow, and at 7, A.M., I found myself standing on the cage that is used for lowering and hoisting in the shaft, beside two pails, each having a inner lining of plate tin, with cover, suitable enough, as it seemed to me, to carry down hot coffee for the miners. These pails, and a conductor’s lantern, were in charge of a man equipped in miner’s costume, similar to our own, who was exchanging remarks with the top man, whose duty it is to signal the movements of the hoisting apparatus.
A gong sounding, we began to descend rapidly, or rather, as it seemed to me, the shaft began to rise around us in a most alarming manor.
The cold air of the outer world, descending and mixing with the warm, saturated air rising from the tunnel, caused a vapor that rendered the light of the miner’s lantern scarcely visible at two paces distance. It was an unpleasant position for a stranger to be in, going down, down, down, with streams of condensed vapor pattering on the head, neck and shoulders; and to relieve the monotony and suspense of the decent, I addressed myself to that man with the “hot coffee” pails.
“By the way, I thought I caught the word ‘glycerin’ spoken by that man who let us down.”
“Have they ever used nitro-glycerin in this tunnel? I mean that terrible explosive agent, which tears everything to atoms. I should like to see some of it, and know all about it; it would give one a sensation that would relieve a fellow of this-this oppressive feeling.”
My companion deliberately lifted the cover of his pail, and taking thence an open slender tube, which seemed to contain clear water, said; “there it is.”
“What! Good–, in this cage? Do you mean to say we are boxed up in this hole with–?”
“Yes,” returning his tin cylinder to his pail, and replacing the tin cover, “that is nitro-glycerin-one of twenty cartridges we are about to use in blasting.”
I reflected; here I was in a box four foot by three feet, no escape from a pail containing enough nitro-glycerin to send us up the shaft, and into eternity for the matter of that, and I had been confounding the “perilous stuff” with hot coffee. There was no help for it now, and as the heavy beat of the steam pumps and warm temperature rendered conversation difficult, I certainly felt as if I had put my foot into it, or something like it.
But we are at the bottom of the shaft.
“Stand clear there, glycerin!”
“All right, sir.”
“Where’s our car?”
“Here, ready; can I help you?”
“Only by keeping clear with your flaring lamps; push on.”
And now, impelled by a brakeman, our car is rapidly driven to a small caboose, or cupboard, some three hundred yards from the shaft, the trip reliever by an inquiry:
“How is it the water’s so high?”
“A pump gave out last night; water’s been gaining since; the machinist will soon fix it.”
My companion now unlocked the door of his little caboose on the left side of the tunnel, examined briefly the signal apparatus, an electric magnet and gong, then the switch or brake, which turns off the current from the wires leading to the heading, and assures himself that whilst charging the drill-holes, no electric spark can pass over the wires by any tampering with the instrument above ground; this done, he resumed the pails, and we now rapidly pushed on the heading, about one hundred yards distant, the way enlivened by a gushing stream of water; ascending the two benches of rock, we now came upon twelve miners, each with his candle, and the foreman busy examining the finished drill-holes.
“Mr. Gregory, will you send your men back?”
“Hands, back from the heading!” Glycerin lads! Pick up your tools; hurry up there, and mind you don’t run foul of this man!”
“Where are your holes?”
“Here they are, good and strong.”
Eighteen holes are now counted, their diameter and depth gauged; those are found to vary from twenty-six to thirty two inches in depth, and at various angles, and in various directions from the face, each of them capable of receiving a cartridge eleven inches long, and one and one fourth in diameter.
“You need not stay, foreman.”
“I’ve no fear; I’ll just help a bit. Don’t mind me I’ve seen glycerin afore.”
Carefully and deliberately a cartridge is removed from the pail; an insulated wire, with priming exploder and cork attached thereto, closes the open mouth of the tin cartridge; and still more carefully the cartridge; with it’s mischievous little wire and fulminating exploder, is now passed into the drill-hole, and pressed down to the extreme end, leaving the wire pendant there from like a rat’s tail; when this performance has taken place in eighteen holes, a count is made- eighteen.
Now the conducting main wire is brought forward and attached to one of those pendant wires, which, by the way, on close examination, consists of two wires, when attached to one of those, the other is carried to one of the double wires of the next hole, until each of the eighteen holes is linked with the one next to it, and that to the next, forming a series of links, the first connected with the connecting, the latter connected with the return wire.
Then two wires, when the switch or break is suitably disposed, connect the cartridges in the holes with the electrical machine, 1,500 feet distant above ground, in the timekeeper’s office.
Now, bear in mind, there is a break, one tenth of an inch from each other, of the points of the wires in each hole, and this break is armed with a sensitive priming, so as the electric spark, as it leaps from one wire to the other, ignites it; this fires the fulminate, and the explosion of the fulminate explodes the nitro-glycerin, and the nitro-glycerin plays the – with the stubborn, tough, solid rock.
But my mining friend is scrutinizing every connection, and now he counts every hole; none have been missed.
We will now turn our backs (with a very satisfactory shrug on my part) on the masses of rock, burrowed with the eighteen drill holes, each charged with sufficient nitro-glycerin to hurl it into fragments, aye, from the very bottom of these holes, and to send a blast of liberated gasses that will hurl a puff of steam and air out of the shaft, 1,500 foot distant.
That pail, I perceive, our companion carries with him. We descend the first bench; at the second he deposits his pail, and we all hurry back to the caboose, where the miner’s lights seem right welcome.
But where is there a recess, a safe recess, where I may avoid the consequences of my curiosity? Narrowly watching the miners, I am aroused by the inquiry, sharp and quick in tone:
“All back from the heading?”
“Look out for yourselves!”
And then our sober, decided friend enters the caboose; the door is locked; the miners converse; I endeavor to secure a position by which a good number of miners are between me and that heading, and sit me down on an iron pipe, which, Mr. Gregory informs me, is to supply air to the machine drills.
“Look out now!”
Instantly, I notice the miners carry their hands to their ears; instinctively I follow suit; the hum of conversation has ceased; a dead silence succeeds; the pulsation of the steam pump throbs; the breath comes quick;- oh this suspense –a singular exaltation of excitement thrills through one.
A rush of air-my hat has gone with it; pitch dark, for every light and lantern is extinguished.
“Who’s got a match?- No one, I bet.”
“Yes; here’s one.”
“A heavy blast, that; she got it that time.”
And now the foreman, our companion and myself, make for the heading; the miners are told to keep back.
We return to where the ingenious arrangement of wires aided by the electric machine, above ground, has affected this discharge.
As we approach within fifty feet of the heading, a warm sweetish vapor is looming up; still on, on, on: here is a mass of rock; move carefully, there may have been a cartridge thrown out unexploded, laying at your feet. If so, don’t trample on it, that’s all.
Scrambling over the masses of torn broken rock, the heading is at last reached-ragged, indented, a scarred witness of the tremendous power of nitro-glycerin.
After carefully noting that each and every hole has been blown out, we return towards the miners. At the second bench, our friend picks up his pail, and assures himself of the safety of the two remaining cartridges.
We soon come to the miners: the word is passed, all safe; another foreman takes in his gang for another eighteen holes, to be drilled in eight hours, the time for each shaft and pushed back to the shaft, the truck running into the cage.
Signal being given, we commence our accent-or, better described, now the shaft rushes down, down, past us.
Daylight once again, and the pleasant warmth of the tunnel is exchanged for the keen north wind, and 6 deg. below zero temperature. We follow the man with the pails, over the drifting snow, to a shanty, where a good breakfast, and a hot and glowing fire, await him.
“Breakfast ready, Hoecako?”
“All ready. Blast go off all right, eah?”
“Made two feet heading-hurry up with that coffee.”
“What do you think of blasting, Mr.-?”
“Well, I think it gives a fellow a sort, of a kind of-new sensation, decidedly.”