Emerald interest heats up

Vancouver — In the autumn of 1998, field geologist Bill Wengzynowski sparked a flurry of exploration activity by discovering an occurrence of emeralds on Expatriate Resources‘ (EXR-V) Goal Net base metals property in the Yukon. A lot of water has since passed under the bridge, and now Expatriate has inked a deal allowing a private company to evaluate the gemstone potential of its adjacent Finlayson land holdings.

Under the deal, the privately held YK Group can earn a 60% stake in two of Expatriates’ projects by paying $80,000 and spending $500,000 over five years. The agreement covers a small claim block that is known to host beryl mineralization in felsic schists, plus the much larger Finlayson base metal property.

Comprising some 3,000 claims in total, the gemstone exploration over the property will be reduced to 500 claims in the third year of the deal and to 200 claims in the fifth. Expatriate will retain a 1% gross revenue royalty on any gemstones, as well as having all of the base, precious and ferro-alloy metals rights. The junior will also receive 150,000 shares in a public company to be formed by the YK Group.

Having spent more the $20 million searching for massive sulphides in the region, Expatriate will make its data available to the YK Group so that it can define its own exploration targets.

The 1998 discovery on the Goal Net property marked the second known occurrence of emeralds in the northern Territories. The first discovery was made in 1997, when Whitehorse-based prospector Ronald Berdahl found vanadium-rich emeralds near the Lened tungsten showing in the westernmost Northwest Territories, adjacent to the Yukon border.

The Lened property hosts emeralds associated with phlogopite schist developed along the contact zone between a rare-element pegmatite and Devonian-Mississippian black shales. The emeralds are vanadium-rich, transparent-to-translucent, and up to 2 cm long and 0.5 cm wide.

The so-called Crown showing marks a larger and more promising zone of mineralization. Realizing the potential economic benefits, Expatriate launched a separate project, known as Regal Ridge. Situated in the southeastern Yukon, between Ross River and Watson Lake, the project hosts emeralds within schists and quartz-tourmaline veins.

Exploration in 1999 defined an 800-by-400-metre area of emerald material, and subsequent sampling and processing of 7 cubic metres of subcrop and talus yielded about 5 kg of colluvial-elluvial placer emeralds. However, only a tiny proportion of the crystals were of gem quality.

In June 2001, Expatriate inked a deal allowing privately owned True North Gems to acquire a half-stake in 93 of its mineral claims covering the initial discovery. Exploration that year demonstrated that emerald-bearing material had been developed in vertical cross-structures as well as within stacked, shallow dipping zones. Mechanical trenching uncovered a new zone of emerald mineralization some 200 metres east of the area 4 zone. Trenching also showed that emerald-bearing horizons occur with greater frequency in the upper, 100-metre section of the deposit.

Early in 2002, True North picked up an additional 22.8 sq. km of ground extending beyond the western boundary of the Goal Net property. The new project area, currently known as Regal Annex, hosts the same geological signature as Regal Ridge. By March, the company had closed a deal to buy a 100% interest in the Regal Ridge property by agreeing to pay $500,000 to Expatriate. Expatriate retains the right to explore for precious and base metals on the property.

This year’s exploration program by True North consisted of mill site construction, geological mapping and prospecting, reconnaissance geochemical soil sampling, drilling and bulk sampling. Road construction and pilot mill installation were completed by early July. The emerald-bearing material was crushed, sized, washed and passed over a moving belt for hand-picking by a 4-person crew.

The mineralization is marked by a Cretaceous granite body, which intrudes chlorite schist and, along with pegmatite and aplite dykes, has deposited emerald and tourmaline mineralization with associated carbonate, sericite and phlogopite alteration of the host rock. The mafic schists occur within the Fyre Lake metavolcanic unit that crops out over a large part of the Finlayson district. The granitic intrusions are enriched in beryllium and tungsten. The mineralized veins form a complex structural network.

True North completed a small 5-hole drill program aimed at determining the continuity of mineralization at depth. The drill intersected zones of alteration with quartz, carbonate, sericite, phlogopite and tourmaline. The company also collected eight bulk samples totalling 114 tonnes from trenches in four different zones on the property. These samples were processed on site, yielding 53.5 kg of emerald concentrate. The concentrate is undergoing sorting, cutting and evaluation.

On the reconnaissance front, the company traced pegmatite float to yet another new mineralized area, the SW 1 vein. Prospecting west of this vein then led to the discovery of three additional emerald showings.

Emeralds are a chromium-bearing beryllium silicate mineral, and are considered the rarest of precious gemstones. Globally, the major emerald districts are characterized by clusters of emerald occurrences. Zambia supplies about 20% of the world’s total annual emerald production, with a reported sales value of US$200 million per year. Other major producers include Colombia and Brazil. Most global production comes from small-to-medium-scale producers who use semi-mechanized mining methods to recover the stones.