Atkins figured the foul-smelling gas was escaping from deep underground pockets, much like the methane.
There were seven of them. Murray, Walt Jacobs, Elizabeth, Atkins, Weston, Wren, and Booker, who walked behind Neutron. The robot had glided along to the mine entrance, the wheels adjusting automatically to the changes in grade. It moved easily even weighed down with the bomb and the heavy roll of fuse.
The party carried two radios to stay in touch with the people on the surface.
“I feel like I’m going on one of my digs,” Elizabeth said, shifting the weight of the two heavy canisters on her back. “I could use a couple grad students to help carry this stuff.”
It was a feeble joke meant to cheer up Walt Jacobs. The man had looked feverish ever since they’d arrived at the mine. His face was pale. He glanced back and smiled at her, and she sensed he was putting on a brave front. They’d just started, and she was already worried he wouldn’t make it.
So was Atkins. Jacobs looked physically weak, unsteady on his feet. He’d also been concerned about Elizabeth, but after watching how easily she carried her packs, he realized she was in better shape than any of them.
At the eight-hundred-foot level, they left the elevator cage. It was the place where the shaft had collapsed. It was totally blocked by fallen rock. They got their first look at the deep room-and-pillar cuts that tank-sized machines known as continuous miners had carved out of the rock face. They were on Level 8.
Atkins found the layout just as Doc Murray had described it. Each level was comprised of a gridwork of three or four parallel tunnels with crossovers that connected them at right angles. As many as twenty-five “rooms” opened onto each side of the thousand-foot-long tunnels. Only the central or main tunnel connected to the air shaft and skip shaft. The air shaft was at one end. The skip shaft, which had once carried the coal to the top, was at the other.
The tunnel’s roof and walls were covered with a thick layer of white powder. Atkins had remembered that detail from his first visit.
“That’s rock dust,” Murray explained. “They mix it with water and spray it on the walls to keep down the coal dust. It reduces the risk of explosions. Dust can be volatile.”
Booker placed his first explosive charges near the elevator cage, chipping out holes in the shaft for five sticks of plastic explosive. He attached the non-1 fusing, crimping it onto the explosives with a special tool, and began to unreel the fuse from the spool attached to Neutron’s back.
They advanced down a tunnel single file. Murray led the way, playing a spotlight on the walls and roof, checking for any sign of fresh cracks.
“Stay as close to the center of the tunnel as you can,” he said. “The roof supports are better in the middle.” The supports consisted of hundreds of steel bolts drilled up into the ceiling, each of them four feet long.
Looking behind a few minutes later to check on everyone’s progress, Murray noticed that Weston and Wren had drifted over toward the side of the tunnel. In the disorienting, absolute darkness, it was easy to get out of line, even with a headlamp.
“Hold it,” Murray told them. He’d noticed a thin crack in the ceiling. “Get back here behind me.”
When the two men were safely out of the way, he jabbed at the crack with the sharp end of an eight-foot- long crowbar he carried. A sheet of rock about five feet wide and an inch thick crashed down, throwing up a cloud of white dust.
“Hope you got the idea,” Murray said. “Stay… in… the… middle of the tunnel. The shoring along the ribs over on the side wall is pretty poor. I’m noticing a lot of cracks.”
With the stop it took them fifteen minutes to advance about five hundred feet to the end of the tunnel. Murray led them into the air shaft. Thick, heavy sheets of plastic covered the opening to the shaft.
“That’s a fire curtain,” Murray said.” A fire breaks out, that’ll give you a little protection. Maybe a couple minutes. They’re mainly used to channel fresh air or to help seal off a tunnel from poisonous gas.” He grinned. “Like I said, it’ll buy you a couple minutes.”
The air shaft sloped down at a steep incline. It was possible to walk on the grade, which had been designed to serve the double purpose of providing an intake for fresh air and an escape route in an emergency.
“We’ll go down about seven hundred feet, then cut down a tunnel on Level 15 and take the skip shaft to the eighteen-hundred-foot level. That’s the end of the line.”
Ever since they’d entered the mine, they’d heard an intermittent rumble deep in the ground. It was the same unnerving sound Atkins remembered from before. It was far below them, the sound, Atkins thought, of mountains of rock sliding together in the earth’s crust.
Before they started down the air shaft, Murray tied everyone to a lifeline. He looped the ends through metal rings in their web belts much like mountain climbers used carabineers to link up to a rope. It was a steep descent. They sometimes had to hold on to the walls to keep their footing. If someone stumbled, the line would keep them from knocking down the others. The air shaft was just over five feet high, so they had to walk hunched over. Neutron moved easily, its orange football helmet passing well below the roof of the tunnel.
There were frequent tremors, none severe. Their faces and hard hats were soon covered with the chalky white powder that fell from the roof like flakes of snow every time the ground shook.
Murray called a brief halt to take another gas reading. Jacobs rubbed his temples.
“What’s wrong, Walt?” Atkins asked. “You okay, fella?” His friend looked like he’d been stricken with a crushing headache. His eyes were clamped shut. He put his hand against Atkins’ shoulder to steady himself.
“I’m fine, just a little wobbly,” he said, wiping sweat from his brow with his sleeve. “I forgot how hot it was down here. It’s like a steam room.”
It was warm, another of the details Atkins recalled from their descent nearly a week earlier.
“That heat’s one of the things that’s got me concerned,” Murray said. “A mine’s usually cool. Low sixties year-round. We’ve got readings in places nearly ninety degrees. This ground is really putting out the heat.”
Atkins still found that puzzling. His best guess was that heavy seismic activity at great depth was causing it. Rock strain generated heat, and in this case, the strain was still building, still putting out energy.
They stopped several times so that Booker could place explosive charges in the shaft. He kept unwinding the yellow fuse line from Neutron.
Atkins marveled at the robot’s ability to make the descent. The engineering was superb. The omnidirectional platform and unique tread system compensated instantly for sudden grade changes. The hydraulics automatically shifted the robot’s center of gravity. It was designed to descend a steep grade.
When they reached Level 15, Murray moved them back into the mine tunnel.
“How far down are we?” Elizabeth asked Murray.
“About fifteen hundred feet,” he said.
Except for a mild headache from the depth, she was holding up well, better than she’d expected. She quietly asked Atkins how he felt.
“Just like a walk in the country,” he said, forcing himself to smile. It was tough, but he hadn’t experienced any panic attacks, which was about as good as he could hope for. Having Elizabeth along helped him for a reason he hadn’t considered: she gave him something else to focus on.
They started through another maze of dark tunnels carved out of the coal seam. The rooms were interspersed with thick columns left in place to support the ceilings. The damaging effects of the earthquake were more apparent at this level. Parts of the roof and walls had caved in, leaving only narrow passageways. With every mild shake of the ground, more dust and rock fell.
It was getting warmer.
Murray called another halt to check his gas meter. He’d been doing this often.
“I’m reading about 4.2 percent methane,” he said. “That’s a hell of a jump since the last time.”
Looking up the dark tunnel, Atkins remembered what Murray had told them about sitting in the barrel of a shotgun.
GUY Thompson, resplendent in a broad-brimmed cowboy hat with an eagle feather in the brim, was monitoring an array of seismographs they’d set up around the periphery of the mine. The instruments were programmed to send signals to the red shack four miles away. The instruments would pick up the effects of the explosion, the intensity of the seismic waves it generated.
Thompson, who was at the red shack, had just gotten them online. The digital instruments indicated a pronounced increase in seismic activity.
