EXPLORATION
rotary blasthole drill-rigs includes two electric models, the recently introduced 1190E and the 1175E that is designed for emerging markets and designed and manufactured in Sandvik’s Jiading works in China. Te latter is designed for single operator mining in soft and medium-hard rocks for coal or metal ores. Te electric power option is preferable in many isolated mines without a reliable supply of clean diesel fuel. Te recently introduced Sandvik 1190E can drill holes of 9-13¾ in. (229-349mm) with a single-pass depth hole depth of 19.8m (65ft), or a multi-pass depth of up to 85m (279ft). Multi-pass drilling requires the installation of a means of adding drill steel, ideally from an on-board carrousel storage.
Improved technology over recent years has tended to reduce rig size for the same duties, also tending to improve mobility. It is an important method study calculation to make in deciding on rig drilling capacity compared to mobility.
Methods choice Although rotary drag bits, with no moving parts, can be applied to only the softest rocks, the rock-cutting element is usually a tricone roller bit of the required diameter. Originally made of hard steel, tricone bits now invariably include tungsten carbide inserts for better rock crushing capabilities. Flushing of the spalled cuttings is usually by compressed air of sufficient delivery pressure and volume to carry debris to the surface.
Sandvik DR461i rotary drill rig with advanced ‘intelligent’ control in transit mode.
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