Eighty meters below the rim of the Quarry Ward, in the underground vault of the world-size absorption sink, Geth Marr stood ankle-deep in warm, greasy runoff. He watched the last steam vents choke out along the north retaining wall.
The vast chamber was silent now, save for the rhythmic drip of water drops falling from the limestone stalactites high above. For four hours, this cave had been a roaring heat-powered fire. It took in the tightly packed solar energy vented from the central lens through twelve thousand feet of water-jacketed piping. The air still carried an intense, dry heat that smelled of scorched shale, glass-fused salt, and boiled sulfur. But the pressure needle on the emergency pipe hub had settled into the green index mark.
Geth wiped sulfur grime from his gray beard with the back of a soaked leather gauntlet. He carried a six-foot iron sounding bar in his right hand. He tapped the dark rock foundation blocks as he walked the outer edge of the heat sink.
“Check the seventh spreading joint,” he called out, his voice echoing off the curved limestone vault. “Venn, did the bronze bolts hold, or did the heat shear the heads?”
Thirty paces to his left, Venn stood on the iron narrow high walkway above the backup sump. He swung a heavy copper check lantern along the pipe rim seams. His face was caked with limestone dust and soot, his wool shirt plastered to his ribs with sweat.
