The large Bulgarian mining concern, Ellatzite Med AD, has purchased and installed two large Suspended Electro Magnetic Separators to separate tramp metal that can easily damage crushers and conveyor belts. The Suspended Magnets have been selected, designed and manufactured by Eriez Magnetics Europe Ltd, based in the UK.

The mining industry is an important sector in Bulgaria’s heavy industry, based on the existence of some relatively abundant and strategic mineral deposits. Many of the major mining companies recognise that equipment needs updating and that any new plant would need to comply fully with all relevant EU standards legislation.

Ellatzite Med AD is a joint-stock company, established in its current ownership structure following privatisation in 1999. The company is involved in the extraction and processing of copper porphyry gold-bearing (Cu-Au) ore and its operations are based on a world-class copper deposit in the Balkans.

Eriez Magnetics Europe Ltd, a principle European supplier of magnetic separation, metal detection and sampling equipment, secured this important contract as a result of the close cooperation between the Eriez Bulgarian representative, Intertech Automation, and the Bulgarian contractor, Geotechmin. Eriez engineers had initially made a visit to the mine and linked up with the team from Intertech who made a detailed presentation to the contractor, Geotechmin. The management subsequently selected Eriez as the supplier for the Suspended Magnets, a contract won against strong European competition.

Ellatzite Med AD ordered two Eriez Model SE775SC2 Suspended Electro Magnetic Separators, complete with Transformer Rectifiers. One important requirement of the contract was to get the Suspended Magnets installed and operating quickly and this was achieved with satisfactory completion within a few weeks of the equipment arriving at site.

The Eriez equipment has been installed at the Etropole copper mine where the copper porphyry ore is extracted from an open-cast mine. This is a large-scale operation and around 12 million tonnes of ore is mined each year. The Eriez Magnetic Separators provide effective removal of general tramp iron from the conveyed material.

The rubber conveyor belt over which the separators are suspended takes the copper ore, now free of its tramp iron contamination, through a 6.3km tunnel to Mirkovo, the company’s headquarters and site of the flotation plant. Here, Ellatzite produces copper concentrate from the Cu-Au ore, annually yielding more than 40,000 tonnes of copper in addition to approximately 1.5 tonnes of gold. The tailings are collected in the Benkovski 1 and Benkovski 2 tailings sites, located in the nearby villages of Benkovski and Chavdar.

The Suspended Magnetic Separators are approximately 2m wide and 3m long, weighing 6.5 tonnes. They are positioned across conveyors carrying up to 2,300 tonnes per hour of ore, into which they project a deep and strong magnetic field. Tramp metal, sporadically appearing in amongst the ore, passes into the magnetic field and is subsequently attracted up out of the burden and onto the magnetic face. A belt, with wipers, moving around the electromagnetic block then transfers the captured ferrous metals away from the conveyor, before discharging into a collection chute.

The selection of a Suspended Electro Magnet is critical to the success of the separation. In many plants, Suspended Magnets of insufficient strength are installed, resulting in crusher and conveyor damage, loss of production and expensive maintenance. Eriez use a bespoke computer programme to firstly determine the magnetic power required to meet a customer’s separation objective and then design a Suspended Magnet to suit.