Highland Valley mine in full swing

At the current mining rate, it would take less than a year for the Highland Valley Copper partnership to deplete an orebody the size of Hemlo. About a quarter of a million tons of ore and waste are mined each day, making it one of the largest earth- moving operations on the face of the globe.

Three companies share in the cash flow of the partnership: Cominco Ltd. (50%), Lornex Mining (45%) and Highmont Mining (5%). Highmont is controlled by Teck Corp. which actually has a 20% indirect interest in the partnership through its equity positions in Cominco and Lornex.

In terms of milling capacity, Highland Valley Copper will rank second to Bougainville in Papua New Guinea when the dormant Highmont mill is transplanted next to the Lornex concentrator 14 months from now. Teck fought hard to have the mill incorporated into the project and its replacement value has been estimated at $200 million.

The $70-million project will increase mill throughput to approximately 145,000 tons per day and probably lead to the closure of the old Bethlehem plant which is rated at 33,000 tons. It will also enable the partnership to consolidate its work force at one location and its electric power facilities. (The operation is the third largest customer of B.C. Hydro and its consumption is valued at about $25 million per year. Most of the power is used in the mill).

Installation of the Highmont mill at Lornex will involve a huge concrete pour of about 20,000 cu yd; and it will be completely integrated into Lornex with a single control room handling the expanded facility.

Disassembly of the plant should begin in the next few months and about 500 contractors will be involved in the over-all program. The agreement for the Highmont mill did not include any of Highmont’s mining equipment which is undersized for the larger mining operation. Mining constraints preclude the Valley orebody being mined at a rate that would supply three mills; so the Bethlehem concentrator will probably become redundant. By incorporating Bethlehem into the operation, another 80,000 tons of ore and waste would have to be mined each day and the logistics of doing so aren’t really favorable, The Northern Miner was told during a visit to what is truly a showpiece in Canada’s mining industry.

In late 1987, Highland Valley Copper completed a $55-million construction program which integrated the large and efficient Lornex mill with the higher grade Valley orebody. Two semi-mobile crushers were installed in the Valley pit and a conveyor system consisting of four main overland conveyors, each approximately 1.25 km long, arranged in two parallel flights. Only one of two fixed crushers used earlier by Lornex is operating at present and it’s dedicated exclusively to ore from the Lornex pit which accounts for about 20% of current feed. (Almost all production from the Lornex pit is ore at the moment.)

The portable crushing and conveyor system will follow mining activity into the pit as it deepens along with the conveyors which move radially from a surge pile located at the rim of the ultimate pit. From a vantage point high above the world-class mining operation, the system looks incredibly efficient. (And you soon recognize that open pit mining is really all about materials handling.)

What the system eliminates is costly truck haulage to the Lornex plant and also a steep climb from the Valley pit. The entire system is controlled by fibre optics which also detect trouble spots such as overheating of motors, metal scrap in the ore, and ripped conveyor belts.

The crushers aren’t cheap and cost about $20 million each. No foundation work is required for installation and they should take about two days each to move once crews learn the procedure. The crushers consist of three modules which can be disassembled easily and moved by a crawler or multi- wheeled transporter. They weigh in at approximately 1,550 tons each and will be moved every 6-12 months.

The partnership expects to recoup the cost of moving the Highmont mill in 4-5 years and Highland Valley Copper President Poul Hansen said the combined crusher/conveyor and Highmont installation will lead to a significant reduction in unit costs. “The key to the success of this operation is low manning,” he emphasized.

Hansen expects copper markets to turn down again and he wants the operation to be among the lowest cost producers in the world. Indeed, he predicted unit costs will be in the lowest 25% of the world cost spectrum. With a production rate of 400 million lb per year, each 1 cents (US) increase in the price of copper is about $4 million on the partnership’s bottom line.

With copper selling for over $1.40 per lb last year, analysts estimated the partnership was making an operating profit that was well in excess of $1 million per day. Mind you, they had a few lean days under their belt before that happened and there will be more in the future.