For more than 30 years, sulfide gold ores were treated in metallurgic plants located in Nova Lima, Minas Gerais, Brazil, and accumulated in the Cocoruto tailings dam. Both flotation and leaching tailings from a deactivated circuit, as well as roasted and leaching tailings from an ongoing plant, were studied for their acid mine drainage potential and elements’ mobility. Detailed characterization of both tailings types indicates the presence of fine-grain size material hosting substantial amounts of sulfides that exhibit distinct geochemical and mineralogical characteristics. The samples from the ongoing plant show high grades of Fe in the form of oxides, cyanide, and sulfates. Differently, samples from the old circuit shave higher average concentrations of Al (0.88%), Ca (2.4%), Mg (0.96%), and Mn (0.17%), present as silicates and carbonates. These samples also show relics of preserved sulfides, such as pyrite and pyrrhotite. Concentrations of Zn, Cu, Au, and As are higher in the tailings of the ongoing circuit, while Cr and Hg stand out in the tailings of the deactivated circuit. Although the obtained results show that the sulfide wastes do not tend to generate acid mine drainage, leaching tests indicate the possibility of mobilization of toxic elements, namely As and Mn in the old circuit, and Sb, As, Fe, Ni, and Se in the tailings of the plant that still works. This work highlights the need for proper management and control of tailing dams even in alkaline drainage environments such as the one of the Cocoruto dam. Furthermore, strong knowledge of the tailings’ dynamics in terms of geochemistry and mineralogy would be pivotal to support long-term decisions on wastes management and disposal.

From the colonial era to modern times, gold mining has played a crucial role in shaping Brazil’s economy, culture, and landscape, particularly in the Iron Quadrangle region. Therefore, resulting waste has accumulated in tailings structures, either from deactivated circuits or plants still in production. The present study reveals the potential assessed based on a set of metallurgical tests, assuming specific scenarios depending on the occurrence modes of interesting economic elements. For Au, calcination, leaching, and flotation are promising techniques to recover this element. Tests indicated that toxic elements such as Sb and As could be effectively reused in the form of glass. The generation of other products from dry cleaning techniques was not effective but promising since there was an enrichment of elements with Au, Fe, Al, and K in specific fractions.

Cross-stream cutters are widely used in the mining and resources industry to obtain representative samples of particulate flows. Discrete element modelling (DEM) and analysis can be used to investigate influences of operational parameters, sampler design and material physical properties in the generation of the Increment Extraction Error (IEE), which when present, results in a frequently biased, non-representative sample. The study investigates the practicality of the rules and recommendations proposed by Dr. Pierre Gy that were developed and established as principles for the correct extraction of samples in industrial sampling equipment. Results validate Pierre Gy’s sampling theory using DEM in a cross-stream cutter of a sulphide gold plant. Importantly, the outcomes indicate that careful consideration must be given to physical ore properties and, consequently, that sampling systems should be developed specifically to each application.

Wastewaters are valuable sources of metals and metalloids and can serve as essential resources for their recovery. Characterizing and understanding the occurrence of metals and other compounds, along with identifying the most effective recovery methods, are key steps in unlocking the potential for reusing these resources. The present study focused on analyzing waters from various mining dams in the Iron Quadrangle (IQ) region of Brazil, which contained metals such as Au, Cu, Ni, Zn, and sulfates resulting from the metallurgical treatment of Au. The results revealed a range of metal concentrations in the neutral zone in three tailings. Additionally, a 3D map was created, and a statistical analysis and an exploration of the processes governing mobility and partitioning were conducted to assess the potential for reuse. Notably, the study identified a high potential for Au recovery, particularly through the utilization of sustainable and cost-effective methods such as nanofibers with biosorbents. Overall, this research contributes to the understanding and exploration of potential reuse procedures for strategic metals in various industrial applications.

As historical waste has accumulated in dams, the interest in studying the feasibility of reusing mining tailings has grown, offering both environmental and economic advantages. However, given the unique characteristics of each site, conducting site-specific assessments is crucial. Building on a detailed evaluation of the Cocoruto Dam in Nova Lima, Minas Gerais, this study presents a technical feasibility and financial viability analysis of three potential reprocessing scenarios. The primary objective was to assess the viability and potential benefits of reusing Au tailings. The proposed methods involve grinding, calcination and leaching, with designs adaptable for existing metallurgical plants. Considering the economic potential of Au in these inactive mine tailings (with an average grade of 0.95 mg/kg and a total resource of 3,350.55 tonnes), multiple factors were analyzed to determine the feasibility of Au production from this source. Analyzed variables included: cut-off grades and tonnage for each scenario; net present value (NPV) calculated with an 8% annual discount rate; a general slope angle of 20 degrees; three possible final pit configurations; different annual production rates (400,000 t, 800,000 t and 1,000,000 t), and various Au ounce values ($1300/oz, $1500/oz, and $1700/oz). From a financial perspective, for all ounce values and an annual production of 400 tonnes, all scenarios prove profitable. However, other risks and parameters should be further evaluated.

Amostradores corta-fluxo e amostradores rotativos são largamente utilizados na indústria da mineração para obtenção de amostras representativas de fluxos particulados. A teoria da amostragem (TOS ou Theory...