Homeabout the companyProcessStaffEnvironmentEntrepreneursHistoryplugWork with us From bedrock to gold ingot Before the gold leaves the Björkdal mine, a long process has taken place, a process that requires patience, time and competence from a variety of professional categories. 1. Exploration Conducted by our exploration geologists in several stages and with different methods. Gold deposits are difficult to find, partly because the concentrations of gold are extremely low, even in high-value deposits. Common methods are block exploration, geophysical measurement, moraine sampling, cuttings and core drilling. After a deposit has been found, an often long process follows to obtain permission to use the land and to mine the gold ore. 2. Planning Mining engineers plan how waste rock will be removed and the ore mined safely and efficiently. They design mining areas and ramps, calculate costs, plan ventilation, electricity supply and water pumping. Production geologists follow the quarry closely, give instructions to the drills and decide what to load as ore. The mining meters measure ointments, localities and rock chambers with the help of total stations, GPS and CMS instruments. They also give instructions (set out) where to drill. 3. Drilling Above ground, large crawler drilling machines with top hammer technology drill large blast holes in a grid pattern according to the mine meters' exposures. The underground mining methods are local drift, pallet and some room and column mining. Underground drilling takes place with the help of electro-hydraulic drilling units with sound-insulated cabins for the best working environment. The resorts are five meters high and the vertical distance up to the next resort is 20 meters. 4. Charging and blasting The drilled holes are loaded with safe emulsion blasting agents, which are reminiscent of wallpaper paste in consistency. Before firing ointments, evacuate the area. In the open pit, large salvos of 20,000–80,000 tonnes are fired a couple of times a week. Underground, a number of smaller salvos of 350-2,000 tons each are fired every day. 5. Rock reinforcement Björkdalsgruvan performs rock reinforcement to reduce the risk of accidents. The first step is scrapping, where you hit the local roofs and walls with a hydraulic hammer in order to get loose loose stones. After that, a layer of plastic-fiber-reinforced concrete is often sprayed on ceilings and walls. Finally, bolting is performed, where holes are drilled and 2.3–5 meter long cam iron bolts are cast into ceilings and walls. 6. Loading and transport Ore and underground gravel are unloaded with wheel loaders and low-built remote-controlled loaders, so-called LHD, in the narrow aisles. The material is then taken to the crusher with trucks, which take 25-30 tons per load. Above ground, unloaded rock is loaded with the help of large crawler excavators. The quarry's gold ore is transported on large rock trucks, which carry 45–65 tonnes per load, to a crushing plant immediately next to the quarry. Infinite rock is loaded to burial mounds. Rocks that have a slightly too low gold content to be enriched at present are called B-ore. It is transported to special warehouses for possible later enrichment. 7. Crusher The gold ore is either tipped directly from the trucks, or loaded with a wheel loader, into the pre- crusher. The coarsely crushed material is sieved and the finest, under 8mm, goes directly to an ore silo. The other fractions continue to a secondary crusher and then to two fine crushers. The material is transported via belt systems and over sieves around the crusher until it is below 8 mm. After this, the material is fed to an ore silo, which holds a total of 5,000 tonnes. The entire crushing process is digitally monitored. 8. Enrichment From the bottom of the silo, the ore, together with water, is transported into the concentrator's rod and ball mills and ground down to less than one millimeter. A new technology here is PSI, Particle Size Analyzer, which makes it easier to adapt production to the grindability of the ore, as it can vary greatly from different ore areas in the mine. Most of the gold is extracted in various stages through so-called gravimetric enrichment. Large industrial shaking tables, spirals and a Knelson concentrator separate the coarse gold, thanks to its high density, from other materials. The finest gold is then extracted with flotation technology. 9. Analysis The various concentrates and waste from the process are dried and then rolled to atomize any lumps, the material is then weighed and transferred to a shredder. From it you get representative samples, whose gold content is analyzed in the mine's own laboratory. These analyzes are then used to calculate how much gold has been extracted from the ore and what gold contents the various production areas in the mine have delivered. 10. End products The extracted gold is divided into four different products, so-called concentrates, which are delivered to various smelters in Europe. The open pit Ore mining above ground is carried out in an open pit that is approximately 1,400 meters long, 250 meters wide and approximately 200 meters deep. Large crawler drills drill downward-facing blast holes in a grid pattern. The holes are then loaded with emulsion explosives and fired in ointments in the order of 20,000–80,000 tonnes. Infinite boulders are loaded into boulders with the help of excavators and rock trucks that load 45–65 tonnes. Ore is loaded and transported to a crusher located next to the concentrator. Above ground, approximately 650,000 tonnes of ore and approximately 2,000,000 tonnes of waste rock are mined annually. Björkdalsgruvan AB Björkdalsgruvan 1 934 94 KÅGE Switchboard : 0910-725750