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underground operations and supplementing the processing with low grade stockpiles has allowed the operations to maximise the processing after suspending the open pit. The plant produces gravity and floatation concentrates that are sold within Europe. Björkdal offers abundant opportunities for continual optimisation of the underground mining, improving processing recoveries, and increasing Mineral Resources, Mineral Reserves.
Location and Permitting:
The Björkdal Mine is located in northern Sweden, 28 km northwest of the town of Skelleftea, near the Boliden mining district which has been mined for a century. There is excellent infrastructure in place, including low-cost hydropower via the grid, paved roads, an experienced labour force and readily accessible technical support. Mining is accepted as a socially responsible and necessary contributor to the local economy. There are no governmental or private royalties on the property.
The Björkdal Mine consists of six mining concessions and 15 exploration permits, totalling 12,950 hectares. The Björkdal Mine is fully permitted for current operations and in the ordinary course of business it operates seven days a week all year round.
The Björkdal deposit was originally discovered through examination of anomalous gold values in till samples in 1983 by Terra Mining AB. Terra commenced open pit mining operations in July, 1988. Open pit mining continued through 1999 under Terra and its successor William Resources, until closure due to low gold price. The open pit mine was reopened in 2001 under new ownership (International Gold Exploration), and continued operation under a succession of owners, Minmet, Gold-Ore, and Elgin. Gold-Ore added the underground mine to the operation, and Elgin continued both the open pit and underground mining.
Over 1.0 million ounces of gold have been produced from Björkdal since 1988.
The Björkdal deposit is located in the prolific Skelleftea mining district, a Paleoproterozoic greenstone belt primarily known for volcanogenic massive sulphide deposits containing high gold values.
Mineralization at Björkdal is typified by Au-quartz hosted veins located within the metamorphic package. These veins are vertical to sub-vertical and strike between 040° and 055°. The quartz veins vary between a few centimetres to over two metres in width. The veining is locally complex, with many cross-cutting thin veinlets.
Au-rich quartz veins are nearly everywhere associated with minor quantities of sulphide minerals such as pyrite, pyrrhotite, marcasite, and chalcopyrite more common non-sulphide minerals such as tourmaline and biotite. Scheelite and bismuth-telluride alloys (i.e., tsumoite) are also commonly found within the Au-rich quartz veins and are both excellent indicators of Au mineralization.
Au morphology is dominantly free or native. Au is also associated with bismuth-telluride, electrum, and pyroxenes. Ag is a minor by-product. Very little is known about its deportment within the deposit, although it is assumed to be associated with the Au in electrum.
Mining & Production:
The Björkdal Mine currently produces mill feed from the underground mine, as well as from a stockpile of low grade material accumulated over the past quarter century. About 75% of the mill feed is generated by the underground operation and 25% from the stockpiled material. Underground mining is accomplished by long hole stoping using a combination of contractors and owner-operated mobile fleet. Access is by dual ramps from the open pit. The plant includes multiple crushers, a ball mill and rod mill, a gravity circuit, and a flotation circuit. Four separate gravity and flotation gold concentrates are produced and sold to smelters in Sweden and Germany. Please click here for operating statistics.
Chris Gregory, General Manager of Australasian Business Development for Mandalay Resources, is a Member of the Australian Institute of Geoscientists accredited Chartered Professional (Mining) and a Qualified Person as defined by NI 43-101. He has reviewed and approved the technical and scientific information on Björkdal contained on this website. Neither Mr. Gregory nor any other qualified person has done sufficient work to classify the historical estimate as a current mineral estimate. Mandalay is not treating the historical estimate as a current mineral estimate and the historical estimate should not be relied upon.