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This paper analyses the importance and environmental impacts of metallic small-scale mining in Chile. This sector is characterized by the exploitation of primarily artisanal copper (Cu), gold (Au), and silver (Ag) deposits, which are dispersed throughout (Chilean) Regions I through VI, with heaviest concentrations in Regions III and IV. In 2000, Chilean small-scale mines employed some 1700 workers (5.1% of total mining workers), and plants with a production capacity of less than 50 tpd accounted for 0.97% (44,603 t) of Cu; 6.5% (3,484) of Au; and 1.1% (13,665 kg) of Ag output in the country. High-grade ore extraction, flotation, gravity concentration, acid leaching–cementation, and mercury amalgamation, are the main metallurgical technologies employed. Following an overview of Chilean small-scale mining, the paper examines the environmental impacts of its production processes, and discusses the legal support and regulatory framework in place for operations. [Copyright &y& Elsevier]

Abundant evidence suggests that the massive global exploitation of copper mines over the last two decades led to mine aging expressed as ore grade reduction, deepening of open pits and underground operations, hardening of the rock, and increasing stripping ratios. These processes have affected the evolution and change of key environmental footprint indicators. Copper ore grade decline seems the most important of these factors and depends on variables including the rate of extraction, ore deposit geological features, introduction of new technologies, the copper price and its co-products, and the discovery and exploitation of new ore deposits. From 2001 to 2015 Chile increased its copper production by 22% and produced overall 80 million tons of copper, more than it produced in the entire 20th century. This paper explores the effects of mine aging on three key environmental footprint indicators: energy and water consumption, and greenhouse gas emissions. Electric energy consumption per ton of copper should grow in the coming decade at a significantly slower rate than in the last fifteen years because of the slowdown of the ore grade decline in mill concentrators. Additionally, a steeper decrease is expected for the emission of greenhouse gases per ton of copper. [ABSTRACT FROM AUTHOR]

Given that most of the mines in Chile are situated in regions with high solar resources, solar power could play a significant role as an alternative solution to satisfy the electricity demand in the mining industry. This paper aims to investigate the feasibility of integrating solar power technology into copper concentrate plants (CCPs). Three commercial technologies (PV, CSP, and hybrid PV-CSP) are considered for integration into four existing CCPs of different sizes and located in different regions. To provide comprehensive analysis, the design, performance and economic assessment of 12 cases are carried and the investment costs are estimated taking into account characteristics of the Chilean market as well as the effect of scale. The performance analysis reveals a strong influence of the degradation rate on the electricity production of solar power plants. The first-year capacity factor of the CSP units is around 68% while it is around 32% for the case of PV units. Due to the degradation in the performance of the components, the lifetime-averaged capacity factor is about 9% lower than that of the first year. The economic assessment indicates that PV is the most suitable technology for integration into the CCPs. The Levelized Cost of Electricity (LCOE) of PV-CCPs ranges from 35.53 to 44.40 USD/MWhe, depending on the size and the location of the plant. The LCOE for the cases of CSP-CCPs and PV-CSP-CCPs ranges from 127.08 to 168.88 USD/MWhe and from 91.89 to 118.91 USD/MWhe, respectively. The modified internal rate of return (MIRR) of the PV-CCPs ranges from 8 to 9%, it discounted pack-back period (DPP) ranges from 5 to 6 years. The DPP PV-CSP-CCPs ranges from and from 15 to 23 years respectively. Overall, the CSP-CCPs are not atractive investments due to high LCOE, longer DPP, and MIRR. However, the sensitivity analysis revealed that its LCOE could be lowered by reducing the investment costs. For instance, a reduction of about 10% in the LCOE is possible if the specific investment costs of the TES is cut to about 10UDS/kW th. Image 1 • We focus on the integration of solar power technologies (SPTs) into the copper mining plants (CCPs). • 12 cases of solarized-CCPs is evaluated technically and economically. • The costs of solar power technologies in Chile (PV, CSP, and PV-CSP) are established. • The LCOE of PV-CCPs is about 4 times lower than that of CSP-CCPs and 50% that of PV-CSP-CCPs. • PV-CCPs and CSP-PV-CCPs are viable options but CSP-CCPs is viable only in sites of high solar radiation. [ABSTRACT FROM AUTHOR]