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By Hasan Nizamoğlu, Z. Abidin Sarı, Aslıhan Demiraslan, M. Deniz Turan, Tolga Depci

In this study, recovery of copper from solid material (obtained by leaching of chalcopyrite with oxalic acid in the presence of hydrogen peroxide) with a copper oxalate structure was carried out selectively using HCl. The chemical composition of the solid was as 29.3%, 9.7%, and 13.3% for Cu, Fe, and S, respectively. Selective recovery of copper by degrading the copper oxalate structure with a low-solubility product (Ksp = 4.43 × 10−10) was performed by conventional leaching in the presence of HCl. The optimum leaching conditions were determined as 5 M of HCl concentration, 318 K of leaching temperature, 120 min of leaching time, 25 ml/g of liquid–solid ratio and 400 rpm of stirring speed. Under these conditions, approximately 77% of copper and 3% of iron were taken into the solution. According to the characterization of the leach residue that was obtained, the oxalate structure was degraded. Moreover, the results of XRD analysis showed that the sulfur (S) and cubanite (CuFe2S3) phases were mostly observed in leaching residues, and this was supported by the SEM-EDX data. Based on the results, it may be stated that selective copper extraction can be obtained from a chalcopyrite concentrate by a two-step leaching method using a conventional hydrometallurgical technique.

By S. Middlemiss

The Indentation Fracture technique is being developed as a tool for use in comminution and mineral liberation analysis. Fracture toughness measurements for a number of mineralogical materials were made and comparisons were drawn between these and properties measured with the Ultrafast Load Cell drop weight apparatus. The technique has also been used as a probe to quantify differences in fracture properties at different areas in the microstructure of a material. In both a Utah limestone and a South African quartzite, material near a grain boundary fractures very differently to that in the bulk. Ongoing work is ultimately aimed at producing a comprehensive fracture model for a multi-mineral system based on its micro-fracture characteristics.

Jan 1, 1994

By J-M M. Rendu

Geostatistics are increasingly recognized as powerful tools for reserve evaluation and grade control. It is also generally accepted that geologic input is required for the results of a geostatistical study to be meaningful. The role of the geologist is significant at all stages, whether it be to oversee the creation of the database, to assist in the statistical and semivariogran studies, to ensure appropriate block evaluation and kriging, or to review the results obtained. However the link between geology and geostatistics is often complex and not well understood. A presentation is made of the areas where geologic input is needed, and of the tools which the geologist should have at his disposition to ensure that his role is fulfilled. Organization of a Geostatisticel Study To be acceptable as the basis for financial investment, a geostatistical reserve estimation should be composed of four phases, the last phase being optional: Phase 1 - Background discussions, Phase 2 - Computation, Phase 3 - Reserve reporting, Phase 4 - Reserve audit. During the background discussions (Phase 1) the role of the geologist is primordial, as it is then that most decisions will be made concerning the geologic factors to be included in the geostatistical model.

Jan 1, 1985

By J. A. Dos Santos

High angle conveyor (HAC®) systems in open pit mining offer many advantages over the traditional, truck only, haulage systems, including: (1) superior energy efficiency, (2) less dependency on petroleum products, (3) less sensitivity to inflation, (4) less labor, (5) less excavation for the amount of ore recovered, and (6) less ramp construction and maintenance costs. Previous studies had revealed the technical and economic feasibility of high angle conveyors. This paper presents the Sandwich Belt HAC® as the vital link to optimization of in-pit conveying systems. HAC development to date is discussed, beginning with studies in 1979, to the first large scale prototype in 1983, to the first commercial unit in 1984, into "the latest commercial installations. Discussion continues with the HAC systems to suit the various open pit mining operations and the corresponding characteristics of the system components, particularly the high angle conveyor. The range of HAC systems from the low capacity (up to 1,814 t/h), low lift (10.7 to 36.6M), highly mobile to the moderate capacity (1,814 to 3,629 t/h), moderate lift (36.6 to 76.2M), intermittently mobile to the high capacity (greater than 3,629 t/h), high lift (greater than 76.2M), semi-mobile, are discussed along with some possible combinations of these.

Jan 1, 1989

By H. H. Murray

Abstract. World reserves of bauxite are abundant. Domestic reserves are limited and as a consequence the United States must rely on foreign suppliers for over 90 percent of its bauxite. Nationalization of many bauxite mining operations, levying of higher taxes, increased production and transportation costs, and attempts to create a uniform market price combined to place the United States in a vulnerable position. Alumina from kaolin, alunite, anorthosite, and oil shale have-been-or are being evaluated. World bauxite reserves are increasing and attempts to establish a uniform price have failed; therefore, it may be many years before domestic non-bauxite sources of alumina can compete with imported foreign bauxite.

Jan 1, 1980

By Thomas A. Colbert

Permanent reclamation of tailing and acid forming mine wastes in the western United States has been largely a losing proposition. There have been few if any successes without actual burial of wastes with soil, overburden, waste rock or other material more amenable to reclamation. Rather than major breakthroughs, development of new techniques has been slow and steady. Revegetation of acid forming wastes with little or no soil cover is now probably feasible. Three key elements include the use of adapted plant species which are now becoming commercially available, lime and selective bactericide for controlling acid, and organic amendments such as manure or sewage sludge. Benefits of this type of reclamation often include reduced mobility of toxic metals and improvements in water quality. With a stringent regulatory regime for mine wastes impending under Strawman II, the importance of good, economical reclamation techniques will become critical to successful and profitable western mining operations.

Jan 1, 1991

By David Atkin

This paper presents methods and results of environmental planning conducted for a proposed coal and iron ore transshipment terminal which would be located on reclaimed land west of Lisbon, Portugal. Oceanographic, navigational, marine, structural, material handling, and financial studies of the terminal were conducted along with the environmental analyses. However, because of the proximity of the terminal to heavily used recreational resources, residential areas, and biologically valuable habitat, anticipating and reducing the environmental effects of the terminal to minimum levels was a very important part of the overall project. The results of the study indicate that even the impacts associated with worst-case conditions would be acceptable because of appropriate pollution control measures and planning.

Jan 1, 1983

By D. W. Fuerstenau, P. C. Kapur

A new method is proposed for measuring the grindability of solids and the energy efficiency of grinding mills. The method is based on a similarity law of fracture mechanics for elastic materials in conjunction with the self- preserving character of the size distributions formed when feed particles are comminuted individually in compression. The single-particle grindability index reflects more closely the inherent resistance of a solid to size reduction than the grindability indices currently in vogue. The performance of grinding mills is evaluated in comparison with the single-particle breakage mode, which has the highest energy utilization or efficiency of all mechanical grinding routes. For a given set of stipulations, the performance index of the commonly used ball mill when grinding dolomite is found m he only 21%. compared to 44% for the high-pressure roll mill, a newly-invented energy-efficient mill. The difference is also reflected in the energy consumed per unit mass offines produced when closed-loop grinding circuits are simulated, which shows that the high-pressure roll mill circuit is invariably more energy-efficient than the ball mill circuit, provided the energy input per pass through the mill does not exceed a prescribed limit. Theoretical upper bounds on the yield of the ground product in a desired size range and lower bounds on the energy investment are calculated from the single-particle breakage mode which has, apart from the highest energy utilization efficiency, a minimum dispersion in size of the comminuted particles. Data on theoretical hounds for seven minerals/ores are presented. It is argued that it is unlikely that a grinding mill can be designed and a comminution circuit constructed whose performance exceeds these bench-mark values.

Jan 1, 1995

By P. Davis

With new mineral deposits found in areas of difficult terrain, and annual production capacity increasing in mines over the last decade, the aerial ropeway is proving to be a viable, economic method of transportation from mine to processing plant. Of the more conventional designs, a bicable ropeway is more suited to difficult country than the simpler monocable. The bicable, however, does have limitations in the difference in levels it can accommodate in one section at a given capacity. This is noticeable where hilly terrain and high capacity imposes a limit on the length of each section. Increasing the number of sections for a relatively short conveying distance tends, in the case of conventional bicable, to unbalance the normally favorable economics of the ropeway. In addition to analyzing hauling rope stresses, other areas have to be considered when looking at high capacity ropeways. Bucket capacity, speed, and the wheel load on track ropes are examples. These and other factors led British Ropeway Engineering Co., of Sevenoaks, Kent, UK, to produce the twin-track system. Using twin track ropes, larger capacity buckets, and, if the height differential warrants, the installation of twin hauling ropes, BRECO produced a ropeway design for areas of hilly terrain and at higher capacities than had been considered suitable for aerial ropeways. Designs have been produced for systems handling 1.5 kt/h (1,650 stph), and the potential exists for expansion to above 2 kt/h (2,200 stph). The arrangement of ropes provides high stability of the cars and is especially suited to areas where high winds occur during normal operation. This development allows the aerial ropeway to be applied economically in difficult areas and at the increasingly high capacities demanded by engineers. Ropeway Transports Limestone to Sudan Cement Plant Maspio Cement Corp. of Atbara, Sudan, will soon use an aerial ropeway to deliver its entire limestone requirement 20 km (12 miles) from quarry to plant. The Atbara plant is located north of Khartoum, near the east bank of the Nile River. The quarry is west of the river, in hills rising from flat desert country. The original transport system was a 24-km (15-mile) railway from the quarry to the west bank and a monocable ropeway that crossed the Nile and continued to the fac¬tory, a distance of about 2.5 km (1.5 miles). This original ropeway had a capacity of 60 t/h (66 stph). With the extension of cement-making capacity in the late 1970s, 2.5 kt/d (2,755 stpd) of limestone was required and a new mono-

Jan 3, 1984

By Edoardo Misano, Magali Schivre, Martino Semeraro, Alain Bochon

"INTRODUCTIONThe Laboratoire Souterrain de Modane (LSM) is an underground research laboratory located in the Western Alps on the French – Italian border. It is located in the middle of the 13km long Fréjus highway tunnel that links Modane (France) to Bardonecchia (Italy) in correspondence of the highest overburden of 1800m. The LSM current activity is mainly based on the investigations about the dark matter and requires very sensitive instrumentation which shall be protected from cosmic rays. To comply with the new legislation about safety in tunnels, the highway tunnels owners agreed in 2007 the construction of a parallel safety tunnel, at an average distance of 50m from the existing tunnel and the laboratory owner CNRS (Centre National de recherche scientifique) also decided to extend the existing laboratory with the construction of a new 17000 m3 cavern allowing the installation of wider and more powerful instruments that could increase chances of success of research. Preliminary studies stated that, considering both geological and functional issues, the most appropriate location for the new laboratory shall be in between the two tunnels and parallel to the existing laboratory (see Figure 1).Hence, the CNRS asked Systra, already in charge of the works supervision of the safety tunnel, to realize the design of the new cavern. The laboratory extension includes the construction of a 40 m long cavern with 300 m² cross section and two smaller tunnels connecting the safety tunnel and the existing laboratory to the new cavern. The minimum distance between the front face of the new LSM and the highway tunnel is about 25 m.The French and the Italian authorities, responsible of the exploitation of the Fréjus highway tunnel, asked the CNRS to develop an accurate study indicating that the construction of the laboratory extension would not have any negative impact on the existing structures of the highway tunnel. The main results of the developed study by Systra are summarized hereafter. The construction works should begin prior to the end of the construction works of the Fréjus safety tunnel in 2018."

Jan 1, 2016

By B. K. Parekh

Sludge obtained during production of magnesium (Mg) metal from electrolyzing of molten MgCl2 contains entrapped magnesium particles. The sludge material containing the magnesium particles is a friable, continuous matrix of frozen salt mixture which may also contain some oxides and impurities. A dry process was developed for recovery of magnesium metal from the sludge, utilizing minerals beneficiation unit operations. The steps included selective comminution, screening, attritioning and tabling. Recovery of the high grade (+90 percent) metal was in the 70 percent range. The process is being commercially used in the U.S. The novel process was also successfully applied to a magnesium-alloy for recovery of metal from the sludges.

Jan 1, 1995

By G. R. Hart

The expected 1990 Clean Air legislation is providing electric utilities with a series of challenges and decisions as the utilities prepare strategies to comply with the resulting regulations. This paper addresses the strategy development of a coal-based utility --the legislation, the process used, the fuel issues, the options available, and the decisions to be made.

Jan 1, 1991

By L. H. E. Weyher

Minerals beneficiation commonly requires initial crushing and grinding so that the mineral phase we seek to concentrate is adequately liberated to obtain a product of specified grade at optimum recovery. To some degree this also is true for coal preparation. In the comminution process we liberate not only the product but also the tailings phase. The true objective is, therefor, to eliminate from the comminution circuit whatever particulate matter has reached specified liberation, regardless of whether the particle is product or tailings material. Overgrinding either of the two phases ties up mill capacity and usually also burdens the downstream processing steps by increasing costs or decreasing recovery, or both. In view of this situation, one would expect concentration steps to be commonly incorporated into the cominution circuit. The reasons this is not done may vary, but probably include the desire to utilize large scale unit operations, e.g., large mills, in conjunction with very simple processes. Hydrocyclones have satisfied this desire but may not always be employed for the right reasons. Hydrocyclones are indeed simple. They also are rugged and forgiving. Unfortunately, these virtues are frequently misused. The direct results are inefficient classification and overgrinding. The indirect results are added costs through recovery losses, unnecessary recirculation, and so on,

Jan 1, 1985

By Terry Owen

Not since 1917 has a foreign company developed a standalone, grass roots gold mine in Russia. With Russia's political changes of the late 1980s, development of mineral prospects once again beckons foreign investors. Cyprus Amax's interest in Russia began before the mid-1991 breakup of the former Soviet Union. In 1990, Cyprus Amax began searching for such an opportunity. Early this year, production will begin at the Kubaka gold project located in the Russian Far East, near the Arctic Circle. The Kubaka project is a 1.75-kt/d (1,930-stpd) open-pit operation that will produce more than 9.3 t/a (300,000 oz/year) of gold. Identifying Russian mining opportunities In late 1990, the first Cyprus Amax people travelled to Russia. The trip was to determine the potential for western firms to develop profitable mines. This encouraging visit suggested that Cyprus Amax focus on the Russian Far East with its mineral riches and its easier access to the United States. The company's initial efforts thus focused on working with the Soviet Union's Northeast Geologic Expedition, the then government agency for exploration and geology in Russia's Far East. After the breakup of the Soviet Union, Cyprus Amax continued working with the same people, but they now represented new independent, nongovernmental entities. For three years, Cyprus Amax investigated numerous deposits. This resulted in the identification of two properties of significant interest, one of which was Kubaka. Location Kubaka is located in the Northern Evensk District of the Magadan Oblast in the Russian Far East. This is an area east of Siberia. The project is situated in a mountainous area of the Kolyma Range, about 300 km (985 miles) south of the Arctic Circle. It is 285 km (180 miles) north of the fishing village of Evensk and 380 km (235 miles) northeast of the silver-mining town Omsukchan. The site is 950 km (590 miles) northeast of the regional capital city of Magadan. Magadan, the political and economic center of the Oblast, has a population of about 150,000 people. It is served by a year-round deep-water port (with icebreaker assist) and an international airport with service to Moscow and Anchorage, AK. Access to the Magadan region

Jan 1, 1997

By L. Alagha, J. L. Corchado-Albelo

To address the U.S. Department of Energy’s critical minerals strategies regarding rare earth elements (REE) in the U.S.A. This study evaluated apatite-rich mine tailing from the historic Pea Ridge Iron Mine (PR) for possible enrichment of REE by the froth flotation process. Comprehensive characterization studies were performed on the tailing samples to quantify the REE content, identify the REEbearing minerals and their liberation behavior. The aforementioned characterization studies were: x-ray fluorescence analysis (XRF), inductively coupled plasma mass spectrometry (ICP-MS), and TESCAN’s Integrated Mineral Analysis (TIMA). The ICP-MS analysis showed that the concentrations of heavy-REE and light-REE were 8000 ppm and 3000 ppm, respectively. TIMA showed that monazite was the major REE-bearing mineral. Additionally, it was shown that monazite and other REE-bearing minerals were strongly locked within larger apatite grains. Findings from the characterization studies suggested that REE could be enriched using phosphate minerals’ direct froth flotation process. Flotation feasibility tests were performed using selected organic and inorganic iron oxides’ depressants, including polyacrylamide (PAM), in-house synthesized hybrid polyacrylamide (HyPAM), chitosan, sodium silicates, and corn starch. Results showed that the depressant’s efficiency at pH 9 was in the following order: HyPAM > chitosan > PAM > sodium metasilicate > corn starch. Zeta potential studies on the selected depressants indicated that chitosan had the highest adsorption on magnetite’s surface at pH 7. Therefore, additional batch flotation experiments using chitosan as an iron oxides depressant were conducted as a function of chitosan dosage. Results indicated that the highest P2O5 recovery of 55% and grade of 28 wt.% were obtained at 150g/t of chitosan. However, the concentrate’s highest total REE enrichment of 1.07% was achieved at a 200 g/t dosage of chitosan. The low enrichment of REE highlighted the complex mineralogy of the PR tailings and the need to implement additional beneficiation strategies before and after the froth flotation process.

Mar 2, 2022

By Yao Zhou

Under the United Nations Convention on the Law of the Sea (UNCLOS), the international seabed area (Area) and its resources are the common heritage of humanity (CHH). Patent rights can be incompatible with the CHH doctrine and its underlying principles because patent holders might charge unjustifiably high prices to license patented technology for exploring and exploiting the Area’s resources (creating a "patent holdup" situation), might choose not to license, or might license exclusively when doing so would contravene CHH principles. However, a reasonable patent licensing regime can contribute to sharing the benefits derived from the Area and promote environmental sustainability. Provisions of the UNCLOS that stipulated compulsory technology and financial transfers were removed in the 1994 Agreement relating to the Implementation of Part XI of the UNCLOS (1994 Agreement), but to promote equity and sustainability I propose a voluntary licensing regime modeled on the concept of reasonable and non-discriminatory patent licensing (RAND) that has been used in other contexts. The International Seabed Authority (ISA) or another entity will need to coordinate and promote this licensing regime through governance of intellectual property (IP) derived from the Area. This proposed approach can better effectuate the CHH doctrine and its underlying principles.

Sep 1, 2014

By Gilbert A. Bonforte, Hugh P. Caspe, Tracy K. Lundin

The Narragansett Bay Commission (NBC) Combined Sewer Overflow Abatement Program is a major effort to address and mitigate discharges from combined sewer overflows in the Providence, Rhode Island area. The proposed system consists of three deep rock tunnel segments totaling 17.8 km (11.1 miles) in length that will provide 860,000 cu m (227 million gal) of storage at depths up to 99m (325 ft). This paper discusses 13.5 km (8.4 miles) of 6.64m (21.8 ft) finished diameter tunnel, four construction shafts, 19 dropshafts and one large diameter pump station shaft tapered from 1 5.2m (50 ft) at the surface to 27.4m (90 ft) at depth. All facilities are in preliminary design.

Jan 1, 1995

By N. Edmonson

The demand for sulfur divides into two major categories: agricultural and industrial. Most of the agricultural demand is related to the production of phosphate fertilizer products. Industrial demand is derived from the demands for a large number of products and is related to a variety of industrial processes, no one of which characterizes it in a simple way.

Jan 1, 1994

By Nathaniel White, Todd Kilduff, Justin Laviolette, Dan Laviolette, Randy Zeigler, Sean Sundermann

The Mitchell Point tunnel is a part of several ongoing efforts to connect the 12-mile-long Historic Columbia River trail between Mitchell Point Outlook to Mitchell Point Drive. The tunnel lies inside the Mitchell Spur entablature basalt geologic feature, extending 647 linear feet utilizing a typical horseshoe section with a height of 14.5 feet. The Oregon Department of Transportation (ODOT) required proper vibration control to minimize potential impacts to Interstate 84 and Union Pacific rail immediately below the tunnel excavations and sensitive, rare plants. The method of designing the vibration monitoring program and the results of its implementation show the iterative process of using monitoring to improve blast design as excavation proceeds, such as reducing air overpressure and COVID-related supply chain-constraints.

Dec 1, 2022

By T. Tamagawa, I. Iwasaki, N. X. Fu, M. Kobayashi

A three-stage fluidizing-bed process consisting of chlorination, selective oxidation and sulfur chloride conversion was tested for processing chalcopyrite concentrate. It was found that the use of excess oxygen was essential for the stable operation of the oxidation reactor. The excess-oxygen gas inevitably causes the oxidation of the sulfide concentrate in the chlorination and sulfur chloride conversion reactors. A new flowsheet is proposed to separate the chlorination and selective oxidation steps with separate flow paths of the fluidizing gases, thereby, preventing the passage of excess-oxygen gas in the chlorination and sulfur chloride conversion reactors. The feasibility of the proposed flowsheet was demonstrated in a laboratoryscale fiuidizing bed setup.

Jan 1, 2002