Leaching/Bioleaching and Recovery of Metals

Hydrometallurgical processes for metal extraction are becoming more and more popular as average ore grades are declining and huge tonnages of tailings and recycle materials containing valuable metals are being accumulated all around the world [...]

Nickel Laterites—Mineralogical Monitoring for Grade Definition and Process Optimization

Nickel laterite ore is used to produce nickel metal, predominantly to manufacture stainless steel as well as nickel sulfate, a key ingredient in the batteries that drive electric vehicles. Nickel laterite production is on the rise and surpassing conventional sulfide deposits. The efficiency of mining and processing nickel laterites is defined by their mineralogical composition. Typical profiles of nickel laterites are divided into a saprolite and a laterite horizon. Nickel is mainly concentrated and hosted in a variety of secondary oxides, hydrous Mg silicates and clay minerals like smectite or lizardite in the saprolite horizon, whereas the laterite horizon can host cobalt that could be extracted as a side product. For this case study, 40 samples from both saprolite and laterite horizons were investigated using X-ray diffraction (XRD) in combination with statistical methods such as cluster analysis. Besides the identification of the different mineral phases, the quantitative composition of the samples was also determined with the Rietveld method. Data clustering of the samples was tested and allows a fast and easy separation of the different lithologies and ore grades. Mineralogy also plays a key role during further processing of nickel laterites to nickel metal. XRD was used to monitor the mineralogy of calcine, matte and slag. The value of mineralogical monitoring for grade definition, ore sorting, and processing is explained in the paper.

Assessment of the extent of man-induced transformation of a subsoil block in upward mining using ore and host rock caving

The study provides a geomechanical assessment of the man-induced transformation of the 1st block at the Kamaganskoye deposit when the mining system is changed to sub-level caving of the ore and host rocks with no possibility of changing the order of reserve extraction. The relevance of the research results from detailed exploration activities that revealed changes in the ore body boundaries and a decrease in the ore grades. The possibility of partial mining of blocks in ore bodies No. 16 and 17 using the ore and host rock caving system has been assessed and the possibility of retaining the upward mining sequence has been established. The sequence of room mining is defined taking into account the changes in the ore body boundaries. The paper presents the results of assessing the stability of the undermined masses of ore bodies No. 16 and 17, as well as the stress-andstrain state of the rock mass at the assumed sequence of room mining. The results of mathematical modeling of the rock mass stress-and-strain state during room mining using the ore and host rocks caving system proved the technical feasibility of this solution.

Optimization of truck allocation in open pit mines using differential evolution algorithm

The allocation of trucks in open pit mines is a field with great potential for optimizing resources and applying advanced computer modeling techniques, mainly because many companies still choose to use manual allocation, which is premised on the decisions made by the operator, being subject to common failures and not reaching the maximum potential that the equipment can provide. Therefore, this work focuses on optimizing the allocation of trucks in order to increase production, reducing queue time and keeping ore grades within proper limits. The proposed algorithm was based on the differential evolution technique, where two types of mutation operators were used: rand/1/bin and best/1/bin, thus verifying the most suitable to solve the problem. The trucks were allocated in the ore loading and unloading process, aiming to improve the production capacity in a virtual mine. The results brought a convergence to the maximum global production, in addition to which, the allocation of unnecessary transport equipment to the planned routes was avoided. The two mutation operators compared had certain advantages and disadvantages, each better adapting to certain types of situations. The proposed technique can still be extended to other areas, for example, in the transport of grain on the road network or in the implementation of an allocation in freight cars that transport grain.

Experimental investigation into the effects of composition and microstructure on the tensile properties and failure characteristics of different gypsum rocks

The present work investigated the differences in the composition and internal microstructure of four types gypsum rock—fiber gypsum, transparent gypsum, alabaster, and ordinary gypsum by X-ray fluorescence spectrometry, X-ray diffraction, scanning electron microscope and Brazilian split test, and analyzed its effects on the tensile strength and fracture characteristics of gypsum rock. For alabaster, fiber gypsum, transparent gypsum, and ordinary gypsum, CaSO4·2H2O is the main component with 72.78%, 72.72%, 72.57%, and 71.51% content, and tensile strength of 1.79, 2.22, 3.22, and 4.35 MPa, respectively. In addition, the fracture line is arc-shaped, vertical, and zigzag for fiber gypsum, ordinary and transparent gypsums, and alabaster, respectively. On the microscopic level, fiber gypsum has an evident striated structure while the gradual increased pore development for alabaster, transparent gypsum, and ordinary gypsum. Gypsum rock has an obvious layered crystal structure with the increase of CaSO4·2H2O, contributing to the phenomenon with a larger grain size and lower tensile strength. In addition, the number of particles for alabaster, transparent gypsum, and ordinary gypsum increased in turn, while their particle size decreased uniformly, indicating that the lower CaSO4·2H2O content, the more sufficient energy accumulation and release. This paper can provide a theoretical basis for the analysis of the mechanical properties of rocks with different mineral composition and contribute to the design for different ore grades mining.

Magnesite and bauxite ores as petrophysical objects of spectral-grade estimation based on electrometry (from the archives of oxide-metric exploration in the Ural deposits)

Research subject. Distribution of magnesite and bauxite ores in mining blocks of deposits according to electrical conductivity in connection with signals of scattered phases of Ca, Mg and Al oxides. Petrophysical objects and differentiation of the properties of oxides detected in the boundary area and at the boundary with dielectrics, the semiconductor range in the geochemical environment of metamorphic formations from carbonate sediments.Materials and methods. An approach of searching for stationary features was applied. First, a study at the elemental level (review) was undertaken. Further, the authors’ electrometric measurements of the deposits were analyzed. Results. In the review part, the analysis of the metal constants – the relative electronegativity of the OEO (Luo and Benson scale), the electronic potentials E0, and the relationship of electrical resistance and pressure in pure elements was performed. The inversion of the properties of CaO ↔ MgO was revealed (for the first time in 2002–2004); Ca was identified as a reducing agent (CaO is a solid dielectric), which contradicts the current ideas about the comparative additivity of light Mg. It was established that MgO is a separate source of semiconductor carriers. Favourable conditions for studying the conductivity during the experimental part of the work were the absolute exchange increments of ore oxides at geological contacts. The properties of ores, rocks and oxides were measured and calculated. The relationships of the varietal growth of conductivity with compaction, increased basicity and magnetic susceptibility (magnetization) were predicted. This, in turn, provides a basis for studying cores, samples from debris, shredding and recycled geo-material, including concentrates, tailings and waste.Conclusions. The spectral properties of scattered oxides with atomic numbers ≤ 20 were identified. The activation effect of MgO and Al2O3 in the ionic medium (CaCO3 = CaO+CO2) was noted. In the phenomena of the semiconductor nature (n- and psources), a version of the donor-acceptor mechanism was proposed. The established properties are a factor in the implementation of measuring identification of oxides and ore grades in the conditions of deposits, both in the estimates of carbonate chemical types of terrigenous fossils, and plagioclase-pyroxene – in igneous ones. Varietal exploration and prototype electrometry were discussed from the standpoint of high-precision interpretation in the potential and replenishment combination of various petrophysical meters.

Investment appeal assessment of Pt-rich and Cu-Ni deposits of Monchegorsky ore district in current conditions

Development potential and investment attractiveness of PGM deposits (Monchegorsky ore district) are discussed. By the late 2020, the reserves of these deposits were approved based on results of a feasibility study review assessment in the State Reserve Commission and TsNIGRI approval. In current mineral market conditions (including high Pd price), the most attractive development projects are Vuruchuaivench deposit comprising 4 areas (Plast 300, Vuruchuaivench, Yuzhnosopchinsky and Arvarench), NittisKumuzhya-Travyanaya occurrence and Loipishnyun area. In terms of reserves, ore grades and proximity to processing plants, these potential mining projects are less expensive if developed concurrently. The paper presents recommendations for PGM deposit opening, development and mining using advanced mining equipment in open-pit and underground mining operations, ore conveying and processing plant tailings disposal to infill underground workings. Economic estimates were made supporting development viability of the above deposits within Monchegorsky ore district.

Modelling Global Nickel Mining, Supply, Recycling, Stocks-in-Use and Price Under Different Resources and Demand Assumptions for 1850–2200

The long-term supply of nickel to society was assessed with the WORLD7 model for the global nickel cycle, using new estimates of nickel reserves and resources, indicating that the best estimate of the ultimately recoverable resources for nickel is in the range of 650–720 million ton. This is significantly larger than earlier estimates. The extractable amounts were stratified by extraction cost and ore grade in the model, making them extractable only after price increases and cost reductions. The model simulated extraction, supply, ore grades, and market prices. The assessment predicts future scarcity and supply problems after 2100 for nickel. The model reconstructs observed extraction, supply and market prices for the period 1850–2020, and is used to simulate development for the period 2020–2200. The quality of nickel ore has decreased significantly from 1850 to 2020 and will continue to do so in the future according to the simulated predictions from the WORLD7 model. For nickel, extraction rates are suggested to reach their maximum value in 2050, and that most primary nickel resources will have been exhausted by 2130. After 2100, the supply per capita for nickel will decline towards exhaustion if business-as-usual is continuing. This will be manifested as reduced supply and increased prices. The peak year can be delayed by a maximum of 100 years if recycling rates are improved significantly and long before scarcity is visible.