Pan Pacific Copper Co., Ltd.

Acid mine drainage (AMD) or acid rock drainage (ARD), the most notorious environmental problem in many mines and underground construction sites, is generally managed using lime neutralization. This approach is effective but unsustainable in the long term, so we introduced the two-step neutralization ferrite-formation process in our previous works as an alternative. However, several important issues related to this new approach-the partitioning of hazardous elements during treatment, stability of generated sludges, and influence of coexisting ions-remains unclear. In this study, real AMD containing zinc (Zn), copper (Cu) and arsenic (As) was treated using a laboratory-type continuous ferrite process flow setup. Partitioning of hazardous elements in the two sludges was elucidated by X-ray fluorescence spectroscopy (XRF) and X-ray absorption spectroscopy (XAS) while the stability of sludges was determined by standard leaching experiments. The bulk of Cu and As species (both As(III) and As(V) based on XANES spectra) were partitioned in the first sludge while ~64% of Zn was associated with the ferrite sludge. In terms of stability, both sludges were relatively inert and released only minute amounts of Zn, Cu and As, all of which were below the Japanese environmental standards. The roles played by two of the most ubiquitous coexisting ions in AMD on ferritization-dissolved silica (Si) and aluminum ion (Al³⁺)-were also elucidated using 10 synthetic AMDs. Between the two, dissolved Si exhibited stronger adverse effects on ferritization than Al³⁺. At dissolved Si above 4 mg/L, Si-O-Fe surface complex formation on amorphous Fe-precipitates or Fe-oxide precursor minerals became extensive, which protected these phases from the dissolution-transformation reactions required to form strongly magnetic magnesioferrite and magnetite. These results suggest that the flexibility and applicability of this new AMD treatment approach could be improved by controlling the dissolved Si concentration prior to the ferrite formation step.

The transient behavior of the multi-interfacial flow can be modeled using recent Smoothed Particle Hydrodynamics (SPH) model.This developed numerical method is fully-Lagrangian particle-based approach, which can track the movement of many fluid phase directly.The advantage of this simulation model is a direct calculation in both of dispersed phase and continuous phase seamlessly.Thereby this model estimates transient behavior of interfacial behavior by predicting the changes of each interface shape.For example, numerical simulations have been performed for different conditions corresponding to different values of surface tension, viscosity and d., and the predicted topol. changes as well as the theor. interfacial shape of droplets can be validated.Based on this model, we carried out relatively large-scale interfacial flow simulations, investigated case studies of metallurgical processing, and evaluated the non-steady state flow of formed from various dispersed phase.

A review discussing the development of the first Japanese owned and operated large oversea copper mine, Caserones.Caserones is the first world class copper mine owned and operated 100% by Japanese companies.It is an open pit mine located in the Andes,160 km southeast of the city of Copiapo, Chile.The equity is shared by 2 Japanese companies, Pan Pacific Copper CO., LTD and Mitsui & CO., LTD.In May 2006, Pan Pacific Copper acquired the concession which includes Caserones as a supergene oxide and sulfide copper prospect.In pre-feasibility study stage, a significant hypogene sulfide ore was identified beneath it.The construction began in March 2010, and the SX-EW plant started operation in March 2013.In July 2014, at the beginning of copper concentrates production, the official opening ceremony was held in Santiago of Chile, with the attendance of Japanese Prime Minister Shinzo Abe and Chilean Mining Minister Aurora Williams.Caserones is estimated to embrace I billion tons of hypogene ore containing 0.34% of copper and 126ppm of molybdenum, besides 300 million tons of supergene ore with 0.25% of copper.The production is planned to last 28 years.Caserones will contribute to the stability of copper supply to Japan, as well to raising Japanese mining experts.