Machines for Mechanical Mining of Hardly Workable and Abrasive Rocks

Mechanical mining is a widely used method for separating material from mined rock in the mining branch, tunnelling, road and construction industries. Depending on the mechanical properties of rocks, most often defined by uniaxial compressive strength, various machines and tools are applied. Apart from rock strength, the efficiency of the mining process is determined by abrasiveness, which affects the rate of tool abrasive wear. Currently, disc mining by static pressure or rear undercutting are the most developed methods. Undercutting can be supported by high pressure water jet or disk oscillation. Mining with drills also utilizes static pressure. In addition to discs, conical picks are applied; they are mounted on cutterheads. In underground mining and tunnelling, there is an increasing need to cut abrasive rocks with a strength of more than 120 MPa in places where explosive materials cannot be used. In the article, the recently applied and developed methods of cutting abrasive rocks characterized by high strength, such as copper, gold, tungsten or platinum ores and diamond deposits, have been presented. Next, the latest machines and machine systems used for their mining are reviewed. Leaders in the mining machinery industry, such as Joy (Komatsu), Epiroc (Atlas Copco), Sandvik and Aker Wirth are developing proprietary designs of cutting machines based on both well-known and completely new ideas.