Broken Hill

BROKEN HILL (EN: Broken Hill; RU: Брокен-Хилл) is the unique, according to the content of lead and zinc, polymetallic deposit within Australia. It has been discovered, and is operated since the 1883.

The deposit (the area is 7.3x0.25 square kilometres) is formed by the quartz-feldspathic gneisses, crystalline schists, quartzites, amphibolites of the Lower Proterozoic age, which have been crumpled into the isoclinal folds. The mineralization is confined to the two of them (the eastern syncline, and the western anticline), which are complicated by the folding of the higher order. The six adjacent ore bodies (the thickness is approximately 150 metres) are concordant with the folding, and have the tabular, lenticular, and saddle-alike shapes.

The main ore minerals are galena and sphalerite; there also exist pyrrhotite, chalcopyrite, arsenopyrite, tetrahedrite, native silver, and others. The veinous minerals are quartz, calcite, Ca-Mg-Fe-silicates, and also garnet, feldspar, fluorite, and others. There may be also found the rare samples of the native copper (the dendrites in the form of fern), and of the native silver (the largest nugget is 45 kilograms), of minerals, namely, cerussite, smithsonite, pyromorphite, calcite, rhodonite, raspite, marshite, and others. Since the start of the operation of the deposit, till the 1976, there have been extracted 120 million tonnes of the ore, with the total average content of Pb and Zn 25%, and of Ag 150 grams per tonne.

The remaining reserves are estimated at 72 million tonnes of the ore (1978). The deposit is being developed by three underground mines, and by one open pit mine. The major extraction is delivered from the two underground mines of the "New Broken Hill Consolidated Ltd." and "Zink Corporation Ltd." companies, which are unified by the united ventilation workings. The depth of the development is approximately 850 metres. The thickness of the ore bodies, which are being developed, is up to 150 metres. The system for the development is using the horizontal layers, with the hydraulic self-flowing filling of the goaf space (by the sand-cement mixture). The transportation of the ore to the ore chutes is performed by the loading-delivering machines, the transportation yet further to the underground jaw crusher is performed within the minecarts with the volume capacity of 7 cubic metres. The annual extraction within the entire Broken Hill deposit is: Pb is 250 thousand tonnes, Zn is 400 thousand tonnes, Ag is 600 tonnes, Cd is 200 tonnes (1981). Along the way, there are extracted Au, Cu, Sb, Co.