- Associated Press - Thursday, May 15, 2014

SOUTH PASS CITY, Wyo. (AP) - The names Patrick Flood and Henry Robert Hindle first cropped up in connection with South Pass City about 1868.

The boom was well underway by then. The hills near Red Canyon teemed with about 5,000 people at the height of the gold rush. The region boasted enough people to warrant a newspaper, which is where South Pass City Historic Site Curator Jon Lane first picked up Flood and Hindle’s trail on his journey to rebuild their arrastra.

An arrastra is a wooden milling machine used to crush quartz so gold can be recovered. Miners brought their gold to the miller, who would charge a flat fee or percentage for his services.

The machine was, and is, crude and inefficient. However, it was made from wood, which meant it could be constructed on site, and cheaply. It was the perfect machine for the short-lived boom at South Pass City, a now defunct mining town and tourist attraction about 35 miles south of Lander.

“It was a flash in the pan,” Lane said of the rush.

By the time the first bust hit about 1870, any trace of the two men vanished. They left behind nothing but their arrastra and a notice of delinquent taxes in the soon-to-be defunct newspaper.

All that’s left of the arrastra is a few dragstones - one side smoothed from crushing and grinding quartz - an iron hook and a photo of the partially scavenged machine. The rest had been stripped in the mad hunt to scrape every last flake of gold dust from the site.

Lane came across a photo of the partially scavenged machine and asked workers at the Division of State Parks, Historic Sites and Trails Central Construction Office if they could build it.

The request was a little out of the ordinary. The five-man crew generally works to restore existing stone and log buildings and structures in state parks. This project had moving parts and would require precise calculations.

“To make a big gear like that, to get them to mesh just right, the math involved in that . the timing of the water wheel, the angle of the paddles,” said Mike Allen, department superintendent, listing off the challenges.

“We had to figure it all out as we went . a deal like this, where you’re starting from scratch and the design needs to be historically correct, I have a real appreciation when I’m doing something like that for what those people were doing back then,” he said. “I can say that.”

In an arrastra, a flume directs water over a wheel with paddles. The weight cranks a pair of gears and drags heavy stones in circles around a basin. Those stones grind quartz drilled and blasted from nearby quarries and hauled out of the hills by miners.

Once the quartz is ground to a paste-like slurry, quicksilver, or mercury, is added. The mercury bonds with the gold and when the entire concoction is washed out of a sluice at the bottom of the basin, the heavier gold remains behind. Melt the mercury off and miners were left with gold.

Of course, the miller took his cut.

“It was a lot of work for little pay,” Lane said. “The search for gold is a common link across humanity. It’s driven technology, it’s driven chemistry.”

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