Pressure Loss and Falling Wrenches

An iron anchor bolt was never supposed to squeal like wet brass. Lana swung her boot onto the fourth rung of the staging ladder and found the steel strut sinking two inches into the rock face, buried in stone that had turned the consistency of warm lard.

"Don't kick, Jati!" Lana yelled down into the pit. "Stop thrashing or you'll dig yourself to the mantle!"

Ten feet below the gangway, Jati was wedged to his shins in gray slurry. The ladder's bottom anchor had ripped free the moment he stepped onto it, dumping him backward into the churn where Pillar Six used to stand. The stone-swimmer had already tunneled up into the high roof vaults, but its wake remained. The floor was boiling without heat, agitated by an ultrasonic thrum that made the fillings in Lana's teeth ache.

"Boss, it's dragging my boots down!" Jati clawed at the wet ladder rail, his knuckles bloody against the flaking rust. "The mud has teeth!"

"It isn't mud," Lana said. "It's ground dolomite."

Above them on the middle staging, Tari clung to the supply rope while Kadek braced his back against the shaking rock wall. The whole lower gallery shuddered under the ceiling's settling weight, shedding plates of brittle shale the size of tea trays.

Lana reached past the ladder rail and snatched the staging's emergency chipping hammer from its iron cradle. The tool weighed eighteen pounds, its fluted steel bit coated in drilling grease, fed by a half-inch armored rubber line dropping straight from the upper gangway manifold. If the wall lost its grip on the upper pins before Jati was clear, all four of them would plunge into forty feet of liquid gravel.

She had to lock that stone before the staging tore loose. Her crew was not dying at the base of Pillar Six.

Lana swung down two rungs, planting her heels against the bowing side rails. She leaned out over the boiling gray silt, thumbing the rotary throttle on the chipping hammer.

She pulled the lever wide. The piston hammered at three thousand cycles a minute, a shrill pneumatic shriek that threw a spray of liquid limestone into her goggles. The slurry did not harden. It splashed like water, churning faster under the high-speed chatter. The tip sank four inches into the muck without resistance.

Jati yelled as the silt rose past his knees. "Boss, it's pulling faster!"

Lana released the trigger and wiped the gray sludge from her facepiece. High frequency was wrong. The beast had sung at a piercing whine to dissolve the rock, but its body had undulated with a heavy, rhythmic thud. The counter-stroke had to match the mass of the stone, not the pitch of the beast's quills.

She twisted the brass collar behind the valve housing, cutting the exhaust feed down by two-thirds. The stroke lengthened with a heavy, mechanical clunk.

She jammed the chisel bit into the slurry six inches from Jati's left thigh and squeezed the trigger.

Clack. Clack. Clack. Clack.

The hammer dropped to forty deliberate beats a second. A deep, bone-rattling thud punched through the fluid rock. The gray soup around the chisel shuddered, then seized. The fluid grains locked together under the heavy acoustic shock, turning from boiling liquid into a rough, gray crust that held the weight of the steel bit.

"Kadek!" Lana barked without looking up. "Drop down and get a grip on his collar!"

"On your heel, Boss!" Kadek scrambled down the rungs, his heavy boots banging against the iron.

Lana walked the chisel in a tight arc around Jati's legs. Each rhythmic punch of the steel bit sent a ring of shockwaves through the slurry, jamming the suspended dolomite particles back into cohesion. The liquid muck crunched into brittle conglomerate under the percussive pulse. It was not solid bedrock, but a packed, temporary gravel bed that resisted the downward pull.

"Grab the harness!" Lana shouted.

Kadek reached down with both calloused hands, hooking his fingers into the shoulder straps of Jati's leather apron. Lana drove the chisel directly between Jati's heels, rattling the hammer at the low cadence until the stone packed hard against the soles of his heavy work boots.

"Now! Heave!"

Kadek threw his weight backward against the ladder rungs, his face purple under the lantern glare. Lana grabbed the cross-strap with her free hand, wrenching upward while keeping the hammer pounding into the crust below.

With a wet, sucking gasp, Jati's legs popped free of the silt.

He scrambled up the rungs on his hands and knees, spitting gray slurry and gasping for air. Seconds later, the lower anchor pins on the ladder sheared off with a sharp metallic snap. The bottom six feet of the iron staging whipped sideways and sank into the churning gray pit, swallowed without a ripple.

Kadek collapsed back against the fifth rung, wheezing through his mustache. "Foreman Budi is going to dock us two weeks of scrip for that."

"For what?" Jati croaked, hauling himself onto Tari's staging platform.

"Venting sixty pounds of imperial air to tamp dirt," Kadek muttered. "He has an invoice for every cubic foot of steam pressure that comes down from the surface."

"Budi can charge it to my union dues," Lana said, racking the chipping hammer back into its iron cradle. "Move. Up to the gangway before the wall coughs again."

They climbed fast, leaving the dying floor of Pillar Six behind. Tari hauled Jati over the top railing of the high rail gangway, rolling him onto the corrugated iron floor. Lana climbed up last, her shoulders burning from the vibration of the hammer.

The upper rail gangway hung thirty feet above the lower gallery, suspended by heavy iron tie-rods anchored into the cavern arch. The rail tracks carried ore carts toward the main refinery bins, but no carts were moving. In the distance, across the vast cavern of Batu Deep, the dim yellow arc lamps flickered in unison, pulsing like dying fireflies.

The city's air supply was wavering.

A deafening groan rolled through the stone above them. It was not the sharp crack of falling slate, but the deep, agonizing grind of a million tons of limestone shifting its weight. The ceiling arch was settling into the hollow space left by Pillar Six.

Directly overhead, bolted to the cavern roof by forged iron collars, ran the eighteen-inch primary manifold line. The thick-walled pipe carried thousands of pounds of superheated, high-pressure air pumped down from the surface steam compressors, feeding the drills, the ventilation shafts, and the lift engines of the entire southern district.

The settling arch pinched the iron collar.

A rivet snapped with the crack of a hunting rifle. Then a second rivet sheared off, ricocheting off the iron tracks ten paces from Tari's boots.

"Clear the rail!" Lana lunged forward, shoving Tari and Jati flat against the corrugated walkway.

The main manifold seam tore open.

A deafening, shrieking roar swallowed every sound in the gallery. High-pressure air blasted from the ruptured seam with the fury of an erupting boiler, dropping the surrounding temperature by forty degrees in a split second. A blinding fog of freezing vapor and white ice crystals exploded across the gangway, coating the iron railings in slick frost.

Tools and loose wrenches rattled across the walkway, skittering off into the black void below. Through the freezing gale, Lana looked up at the pressure gauge mounted on the gallery stanchion.

The brass needle was spinning backward, plunging toward zero.