Anglesey’s plans for Parys Mountain holds historical significance

If Anglesey Mining and parent company, Imperial Metals (TSE), are successful with plans to bring on stream the Parys Mountain project in North Wales, it will become the first base metal mine of its type to go into production in the United Kingdom in about 100 years. It will also open a new chapter in the operating history of Parys Mountain which began at the onset of the Industrial Revolution, although evidence exists that some mining activity took place in Roman times.

Surface deposits were exploited in the mid-1700s when Parys Mountain became the world’s largest copper mine. Open pit mining ceased in 1800 as shaft mining techniques were introduced from Cornwall, and production continued into the early 1900s when all significant mining operations came to an end.

The property attracted the interest of several Canadian mining companies in the 1960s and 1970s. Cominco (TSE), for example, is credited with having “fought and won” an exploration battle by a series of drilling campaigns and by methodically and systematically picking apart the complex geology.

In 1985, Imperial Metals obtained an option on the property which is now held by its British- based subsidiary, Anglesey Mining, a public company listed on the London Exchange.

Hugh Morris, chairman of Imperial and Anglesey and a former Cominco executive, said that once the geology was understood the approach to exploration at Parys Mountain was straightforward.

“The task was simply to drill and drill, and if in doubt, drill again,” he said.

The Parys Mountain project is currently reported to contain an estimated mining reserve of 4.79 million tonnes grading 1.49% copper, 3.03% lead, 6.04% zinc, 69.25 grams silver and 0.446 grams gold per ton. Morris said the property is still considered to have “excellent” exploration potential.

With an independent feasibility report in hand, Morris is currently investigating financing avenues to bring Parys Mountain to production in 1992 at a rate of 1,000 tonnes per day. But before this decision was reached, Imperial (and Anglesey) carried out an underground program which included 900 metres of development, 130 drill holes and bulk sampling.

A pilot plant was built on surface for processing of the bulk samples drawn from the separate lenses underground. It included crushing, grinding and selective flotation facilities which have the company confident the deposit will produce three salable concentrates; zinc, copper and lead, with the gold and silver reporting to both copper and lead. Concentrates produced from the pilot plant have already been sold to the Pasminco smelter at Avonmouth, and the expectation is that zinc will account for about 60% of revenues once production begins.

Anglesey’s recent underground program confirmed good ground conditions, and it provided information to determine what mix of mining methods will be most appropriate for the steeply dipping White Rock zone and the deeper, relatively flat-lying Engine zones.

Before production could begin, the Morris shaft would need to be deepened (mining would largely take place between 304-760 metres) and more underground development would be required. A full scale mill facility would also need to be built so that it would provide for a projected mine life of at least 15 years. The property is accessible by road and near all necessary infrastructure to support a mining operation.