Fine Gold Gravity Concentrate Upgrading Research

This project researched the best means of removing fine gold particles from sluice box concentrate.

Project Overview

Placer mining has been a cornerstone of the Yukon’s economy and culture since the Klondike Gold Rush of 1898.  Currently there are over 100 family based placer mines with a combined gross income of more than $50 million a year. Placer mining is especially vital in the Yukon’s rural areas, including Dawson, Mayo and Haines Junction.

But as the richer streams are exhausted, placer miners have to work harder to reap their rewards. They are mining lower grade ground and areas with fine gold. And the industry needs to reprocess tailings (the material left behind after mining) to recover gold that was lost in previous eras.

Many of the sluice box concentrates contain very fine flattened particles in a mixture of high density minerals. Separating these coarse and fine  particles can be tedious.  The coarser gold is usually hand-pickedand magnetic minerals such as magnetite and tramp iron are removed with hand held magnets.

In the Yukon and Alaska, the finer gold particles are collected in small sluices, concentrating tables and gold wheels. This is a safe process but it doesn’t recover all of the gold. In the developing world, fine gold is recovered by mercury amalgamation. When gold comes into contact with mercury, the two substances mix to form an alloy. This method can collect very small gold particles but is hazardous if not done carefully.

This project involved lab and field testing of various placer concentrates to determine the best equipment and methods for recovering more fine gold particles.

  • Randy Clarkson, Klondike Placer Miners' Association
  • Rob Cooke, Project Officer, Cold Climate Innovation, Yukon Research Centre