Wear and Friction Effects on Energy Consumption in the Mining Industry
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Kulumisen ja kitkan vaikutus energiankulutukseen kaivosteollisuudessa
Mining is very important globally. The total amount of mines worldwide is estimated to be 100,000–150,000 –. Mining’s share of global energy consumption is ~5% –. Previous studies made on vehicles ,  and paper machines  indicate that even 20–30% of total energy is lost due to friction. Similar studies on the energy losses due to wear have not been made. This thesis is divided into two parts. In the first part, the global mining industry, energy consumption in mining, and wear and friction in mining are examined. In the second part, case studies of highly energy consuming devices, a haul truck, a jaw crusher, and a grinding mill, are made. From all mines, 70–80% are surface mines and 20–30% are underground or mixed mines. The largest mining countries are China, USA, Australia, India, and Russia . The mining process can roughly be divided into three operational stages: extraction, haulage, and processing. In addition to these three, there is the group of supporting activities. When the energy consumption distribution in surface and underground operations was studied it was discovered that most of the energy goes to processing and sup-porting activities. In the case studies the energy losses due to friction are examined by making energy distribution models. Previous studies and literature on this field was used as a frame of reference in this work. The effect of wear is evaluated by calculating the costs caused by replacement parts and wear-related maintenance. The obtained results indicate that friction losses in the rigid frame haul truck are 24%, in the jaw crusher 30%, and in the grinding mill 50% of the total energy consumption. The annual costs of wear are in the haul truck 40,000€, in the jaw crusher 100,000€, and in the grinding mill 825,000€. The total annual costs of wear and friction compared with the purchase price of a new device are 28% in a haul truck, 13% in a jaw crusher, and 34% in a grinding mill. Energy savings can be obtained with improving energy efficiency, planning the mining operations and maintenance, and with material selections.