Randy Clarkson believed he’s developed a gold recovery tool that will be found on every placer mine in the Yukon within five years.

The invention didn’t come easy. In fact, Clarkson was about to throw in the towel last fall after extensive research wasn’t returning the results he was looking for.

An engineer who’s worked with placer miners for the last 30 years, the executive director of the Yukon Placer Mining Association knew there had to be a better way to capture the last and tinniest flakes of gold that are regularly missed.

Clarkson explains in an interview this week the traditional sluice box will generally turn 20,000 cubic metres of paydirt into one cubic metre of concentrate.

Miners use an array of methods to recover somewhere between 70 and 80 per cent of the gold from that one cubic metre, whether it be a smaller and specialized sluice, a gold wheel, shaking table....

But it’s that 20 or 30 per cent of gold that is too fine to be recovered with conventional methods, even too fine to be captured by traditional hand panning, he says.

Miners typically take that last bit of paydirt and stuff it away in coffee cans, hoping they and their family will some day find the countless hours to spend over a table pulling out the tiny flakes of gold using a fine paint brush.

You’ll find cans full of the stuff at every placer mine, he says.

“In the placer field, the only thing more valuable than gold is time, and nobody has time to do the hand picking.”

So it was with a desire to find something new that Clarkson set out on his quest, supported by a $500,000 research grant to advance the project along with other corresponding research in the gold fields: $190,000 from the federal government; $154,000 from the Yukon’s Department of Economic Development; $100,000 from the Cold Climate Innovation program at the Yukon Research Centre and $55,000 from the placer mining association.

Inventing something that could do the job has been talked about for years in the industry, and it was four years ago that Clarkson started walking along that path. Two years ago he received the funding and began the official research.

Last fall while working alongside retired university professor Dan Walsh at the University of Alaska Fairbanks, Clarkson was near wits’ end. And then one day it happened.

His idea began to show promise. Together with Walsh they refined the details, the correct ratio of concentrate to water, and exactly how long to keep the mixture grinding away in a modified rod mill built from scratch, starting with a regular cement mixer.

The principle is simple.

What’s left over in the coffee can is small granular waste material, mixed with the tiny pieces of gold.

When you crush the granular material, it turns to dust. When you crush the gold, it flattens out.

It is said that an ounce of gold is soft enough – but tough enough – that it could be pounded so flat it would cover an entire city block.

Clarkson explains his rod mill turns the granular waste to dust while flattening out the gold, so that when the material is removed from the tumbler and sifted through a fine screen, nothing remains but the flattened gold.

Cost of the roller mill is less than $2,000, including the cost of a household cement mixer, and the other pieces of the apparatus that can be manufactured locally.

The inventor doesn’t plan on selling his design, or building the roller mills and selling them. Rather, he intends to make his design and operating instructions available to the public, as it was public money which supported the research.

Clarkson says the printed material should be available online early in the new year.

“It’s applicable to all placer mines,” he says, adding that it will also be useful at some types of hardrock gold mining.

Clarkson says he spent last summer in several gold rooms in the Dawson and Klondike region testing the mill and its efficiency, and the results even made him a little bit giddy.

“It works better than we thought,” he says, with a confident grin, while displaying his mill at this week’s annual Yukon Geoscience Forum.

Clarkson says placer miners will cover the cost of the rod mill in its first hour of operation, and he expects it will be found at every mine site within five years.

It’s not high-tech or complicated to build, it’s not difficult to operate and there are no permits required, he points out.

Clarkson says the rod mill will capture 99 per cent of the gold from the 20 or 30 per cent missed in the main operation, the 99 per cent of the gold sitting in all those coffee cans waiting for somebody with a fine paint brush to come around.

“It was designed so that placer miners have more time.”

Those attending this week’s geoscience forum heard there were 160 placer mines operating in the Yukon this year, producing 54,000 ounces of gold at a total value of $60.1 million – and another 5,000 ounces are expected to be reported later.