Painstaking search required to find Saskatchewan's gold and diamonds. (Technology).

It is highly likely that significant reserves of gold and diamonds lie beneath the fields and forests of Saskatchewan, waiting to be discovered. Unfortunately, identifying the location of profitable deposits is about as easy as finding the proverbial needle in a haystack.

Diamond ore, for instance, is considered high grade when a ton of ore contains just half a gram of diamond. Since it is all but impossible to find high-grade ore by looking for the diamond itself, exploration companies look for several other more common minerals that typically indicate the presence of diamonds, These minerals are characteristic of one of the most common hosts of diamond -- kimberlite. A number of kimberlite pipes have been discovered in the province during the past decade. However, even when kimberlite pipes are found, the deposits must be carefully studied to determine if diamonds are actually present, and in sufficient quantities to warrant mining activities.

Saskatchewan is on the cutting edge of several techniques used to process exploration and ore samples that may contain precious minerals, such as gold and diamonds. We also have the only commercial plant capable of processing these exploration samples.

Using gravity, magnetic, and electrostatic separation techniques, processing methods can narrow down the search for kimberlite indicator minerals to a 20-gram sample from 10 kilograms of sample material. Once this heavy mineral concentrate is obtained, a labor-intensive examination of every grain using a microscope is required. Grain "pickers" must have very high levels of expertise and experience to identify the indicator minerals. It takes up to two hours to sort through the 20-gram sample, and often just a few grains of interest are identified.

The work is not over yet. Information on the shape and texture of each indicator grain is often required by the exploration company and a chemical analysis of the picked indicator minerals is undertaken using an electron microscope. The entire painstaking process ultimately yields data that are essential to exploration activities.

Already, several significant diamond deposits have been found in Saskatchewan, at Fort a la Come near Prince Albert, and analysis is underway to determine the feasibility of commercial mining there.

Gold exploration is equally difficult and sample processing is just as finicky.

Millennia ago, gold deposits occurring at the surface of the bedrock under Saskatchewan were scraped off and dispersed by glacial action. As a result, it is possible to find trails of tiny grains of gold fanning out for several hundred metres from a source point.

In order to follow the gold trail, exhaustive sample processing has to be undertaken. All the gold grains must be separated and recovered from the glacial till samples and -- considering that there might be as little as a kilogram of gold dispersed over an area of several tens of thousand square metres -- this is another painstaking task. The size and texture of every grain must be studied under a microscope and each grain is weighed. The grains take on different shapes the further they are transported. Typically, "fresh" grains with sharp edges are found closer to the source, while grains further from the source are flattened, with rounded edges.

So by studying the grains it is often possible to follow the trail of gold back to the source point by analyzing the data for trends and plotting the data on a map. This map may then indicate a gold dispersion fan, pointing the way to a source. The source can then be located and sampled to determine if the material is worth mining.

Although there are no working gold mines in Saskatchewan at the moment, a number of profitable gold mining operations have been carried out here in the past. With the advance of exploration and sample processing technology in this province, it is likely that gold mining will also be part of Saskatchewan's future.

Dave Quirt is a Research Scientist with the Environment/Minerals Division at the Saskatchewan Research Council.