During their long walk they passed through several doors which, as Derrick was told, served to regulate the currents of air constantly flowing in and out of the mine, and kept in motion by the great fan at its mouth. Whenever they approached one of these the mine boss called, loudly, "Door," and it was immediately opened by a boy who sat behind it and closed it again as soon as they had passed. Each of these boys had besides his little flaring lamp, such as everybody in the mine carried, a can of oil for refilling it, a lunch-pail and a tin water-bottle, and each of them spent from eight to ten hours at his post without leaving it.
Finally Derrick and the mine boss came to a junction of several galleries, a sort of mine cross-roads, and the former was told that this was to be his headquarters, for here was where the trains were made up, and from here the empty cars were distributed. At the farther end of each of the headings leading from this junction two or more miners were at work drilling, blasting, and picking tons of coal from between its enclosing walls of slate. They were all doing their best to fill the cars which it was Derrick's business to haul to the junction and replace with empty ones. There were also a number of miners at work in breasts, or openings at the sides of the gangways that followed the slant of the coal vein, who expected to be supplied with empty cars and have their loaded ones taken away by Derrick. These breast miners filled their cars very quickly, as the moment they loosened the coal it slid down the slaty incline, above which it had been bedded, to a wooden chute on the edge of the gangway that discharged it directly into them.
As Derrick was told of all this, he realized that he and Harry Mule would have to get around pretty fast to attend to these duties, and supply empty cars as they were needed.
What interested him most in this part of the mine was an alcove hewn from solid rock near the junction, in which was a complete smithy. It had forge, anvil, and bellows, and was presided over by a blacksmith named Job Taskar, as ugly a looking fellow, Derrick thought, as he had ever seen. Here the mules were shod, tools were sharpened, and broken iron-work was repaired. It was a busy place, and its glowing forge, together with the showers of sparks with which Job Taskar's lusty blows almost constantly surrounded the anvil, made it appear particularly cheerful and bright amid the all-pervading darkness. Nearly every man and boy in that section of the mine was obliged to visit the smithy at least once during working hours. Thus it became a great news centre, and offered temptations to many of its visitors to linger long after their business was finished.
After pointing out to Derrick the several places at which his services would be required, the mine boss left him, and the boy found himself fully launched on his new career.
He soon discovered that Harry Mule knew much more of the business than he did, and by allowing him to have his own way, and go where he thought best, Derrick got along with very few mistakes. Among the miners upon whom he had to attend he found brawny Tom Evert, stripped to the waist, lying on his side, and working above his head, but bringing down the coal in glistening showers with each sturdy blow of his pick. When he saw Derrick he paused in his work long enough to exchange a cheery greeting with him and to dash the perspiration from his eyes with the back of his grimy hand; then at it he went again with redoubled energy.
At the end of one of the headings Derrick found another acquaintance in the person of Monk Tooley. He scowled when he saw the new driver, and growled out that he'd better look sharp and see to it he was never kept waiting for cars, or it would be the worse for him.
Twice Derrick started to leave this place, and each time the miner called him back on some trivial pretext. The boy could not see, nor did he suspect, what the man was doing, but as he turned away for the third time, Monk Tooley sprang past him with a shout, and ran down the heading. Derrick did not hear what he said, but turning to look behind him, he saw a flash of fire, and had barely time to throw himself face downward, behind his car, when he was stunned by a tremendous explosion. Directly afterwards he was nearly buried beneath an avalanche of rock and coal.