The railing creaked and Cate quickly leaned back, feeling a sudden rush of vertigo. “Whoa.” Beneath her feet she felt the juddering of the rock drills and hammers as they pounded the dense material below her. Normally for mining, they’d use explosives, but given they knew there was a drop of around a thousand feet underneath them, the work was carried out in layers – the rock cut and drilled, excavated away, testing done, and then another layer carved out.

The foreman rose from the pit in a drop-cage, waved, and took off his glove to shake Cate’s hand. He nodded to Jack.

“We’re down to the last sections, Professor Granger. The equipment will be withdrawn and then we’re going to pin-blow the bottom layer of diorite; let it drop into the cavern below. It’ll give you a nice neat hole with a strong structure at its edges.”

“How deep?” Jack asked.

“We had to cut in two hundred and twenty-five feet… all within a few weeks.” The foreman tilted his hard hat back on his head. “Not bad if I do say so myself.”

Jack whistled. “We could have just used Heceta Island’s Viva Silva Cave, that’s only a few dozen miles south, and is one of the deepest caves in the continent – drops down about eight hundred feet – would have saved a lot of digging.”

“I know it.” The foreman said. “And that cave narrows down to cracks – we’d never get equipment into its basement. Better to start here with room to work. Just take the top off; bit like eating a boiled egg – break through the shell, and the rest is breakfast.” He winked at Jack.

Jack grinned. “Guess so.”

The grinding intensified, making Cate and Jack wince.

“How long until you break through?” Cate yelled.

The foreman turned and looked back down into the hole. Small backhoes, mobile cutters and jackhammers were moving slowly up ramps and into lift cages. Bore holes had been drilled around the edges of the pit, each the size of a soda can, and ready to have an explosive charge packed into them.

“Ten minutes,” he said. “No need to leave, as the charges are rigged to blow downwards. Just keep your safety glasses on, and lean well back.”

“Great. I’ll stay.” Cate looked to Jack and nodded – she meant both of them.

Klaxon horns blared, and the remaining crew rose slowly in cages, leaving nothing behind on the rock floor. Cate marveled at how clean the surface looked. Though it was rough-hewn flooring, it was mostly swept clean, probably, she thought, to keep the chance of flying debris shards to a minimum. The explosives ringed the hole, each had a flashing red light on top, the wires to each and then all the way up to a console inside a toughened Perspex booth, set up a few feet from where they stood.