Crystal Peak is largest known garnet deposit in the world

Crystal Peak Garnet, owned by Polestar Exploration (VSE), is probably the largest known garnet deposit in the world according to Vice-President Robert Wolfe. The deposit, near Hedley, B.C., measures over 800×300 metres laterally and has been intersected by drilling from surface to a depth of 300 metres, and remains open to depth.

Wolfe estimated the deposit contains over 100 million tonnes, although he noted that the project would require only a fraction of this. Drill-proven reserves total two million tonnes with an overall grade of about 80% garnet. The impact of mining operations to the area will be limited since the companies plan to mine for only 4-6 weeks per year. This will provide enough annual feed for the 225-tonne-per-day operation.

Capital cost of the project is modest; estimated at $2.5-3 million. Milling technology for the plant is relatively simple. The ore is crushed, screened, and garnet is split from the quartz/calcite waste by magnetic separation. (The garnet is slightly magnetic.)

The plant is expected to produce about 60,000 tonnes of clean garnet per year. Of this, about 10% will size between 8 and 12 mesh, 80% will size between 16 and 40 mesh, and 10% will size between 60 and 120 mesh. The principal market for garnet is in the sandblasting market (16-40 mesh). Garnet offers a distinct advantage to silica sand in that there is no danger from silicosis. Wolfe noted that silica has been banned from use for sandblasting in Europe since the 1950s because of the danger of respiratory disease, although it is still in wide use in North America.

Copper, nickel and coal slags are also potential competitors in the sandblasting market. Wolfe noted that the Fisheries department recently banned the use of copper slags for bridge sandblasting because of their associated heavy metal content.

The heavy metal content in slag products is a major drawback in that the material is designated as hazardous and must be retrieved after use and properly disposed of — all that adds to its cost. The North American market for blast-cleaning abrasives is currently estimated at five million tonnes per annum while current North American garnet production is estimated at only 65,000 tonnes per year.

The limited use of garnet for sandblasting is primarily related to its current price at about US$250 per tonne.