A systematic review of paste technology in metal mines for cleaner production in China

Cleaner production is an integrated preventive environmental strategy intended to minimize waste and emissions and maximize product output. The mining industry continually supplies raw materials to other industries, which inevitably leads to enormous emissions. In recent decades, mining engineers have examined many pathways to advance the implementation of cleaner production practices, of which paste backfill is one of the representative technologies. Moreover, this technology is an effective practical approach for the management of process tailings, the largest source of mining waste, since this technology offers significant environmental, technical, and economic benefits. However, due to the more stringent requirements of clean production, the greater the depth of excavation is, the lower the grades of ore (or the more abundant and finer the tailings are) and the longer the distances of paste transport are, and the application of paste backfill technology encounters increasing challenges. For this purpose, the paper presents a systematic review of tailings paste applications in mines for cleaner production. First, the basic concepts and characteristics of paste technology, typical compositions of the paste system, and development progress of the paste practices in China are comprehensively introduced. Second, the latest research on core paste technology is elaborated, such as tailings thickening, pipeline transportation, multiphysics mechanisms, and new paste materials. Third, a few typical engineering cases of underground paste filling, open pit or ground collapse backfilling, and tailings paste stacking are described, and their engineering backgrounds, key equipment, and operating parameters are studied. Finally, the challenges and future research direction of paste technology, such as paste backfill in deep mining and paste systems with a large capacity, low cost requirements, intelligent control, and multiphase paste materials, are identified to promote cleaner production practices in mining.