COST-CUTTER The History of Highland Valley Copper

Discovered in the early 1960s by Egil Lorntzsen, the Lornex orebody was the first porphyry copper deposit developed in British Columbia’s Highland Valley. Shortly thereafter, the larger and higher grade Valley orebody was found a few kilometres to the north. Many copper-bearing surface outcrops were mined by Native people and, by the turn of the century, white settlers used horse-drawn carts to haul ore to nearby Ashcroft where it was crushed and crudely processed.

The considerably more sophisticated Lornex mine came into production in 1972 and Lorntzsen remains a honorary director of the company he founded — Lornex Mining. When the discovery was made, it was evident that detailed exploration would be required to outline an economic ore deposit. So Rio Algom was brought in to joint-venture the property; it now controls 68% of Lornex. Teck Corp. is the next largest shareholder with 22.3%.

The plant was designed, 15 years ago, to treat 31,300 tons per day which was later optimized and increased to 39,000 tons. In 1978 the decision was made to expand the Lornex concentrator with a third line utilizing a large semi-autogenous grinding (sag) mill. The expansion was commissioned in 1981, and by 1986 the 3-line concentrator had achieved an average milling rate of 80,000 tons per day from the Lornex orebody.

The Valley orebody was discovered by Valley Copper Mines, an exploration company controlled by Cominco. A claim boundary divided the orebody, with 80% going to Cominco and the remainder to Bethlehem Copper Mines. Cominco later purchased 100% ownership of Bethlehem which had already developed a small, but highly successful, mining operation on a different orebody nearby.

Valley ore was first treated in the Bethlehem concentrator in January, 1983, and throughput increased steadily until 1986 when it reached 27,000 tons per day. Low base metal prices, which have prevailed since 1982, set the stage for the combining of the Lornex and Cominco operations.