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By G. L. Smit

The Buffelsfontein Gold Mining Company is situated in the Klerks-dorp district of the Province of the Transvaal in the Republic of South Africa, approximately 100 miles west of Johannesburg. Gold production commenced in January 1957 and Uranium treatment of residue slimes as a by-product started in July 1957. The mining property is 5435 mining claims in extent, the equivalent of 7,988 acres or 12.5 square miles. The mine was initially exploited by the Pioneer Twin Shaft System, consisting of a 26 feet diameter down-cast shaft and a 22 feet diameter up-cast shaft, sunk in the north-west area of the mine to cater for the hoisting and ventilation requirements for a milling rate of 150,000 tons per month.

Jan 1, 1964

By Thomas Bubanovich

Engineers at the Freeman United Coal Min¬ing Company, located in West Frankfort, Illinois, have been using a computerized production planning and maintenance reporting system, which have been designed exclusively for underground coal mining. This paper will explain a dynamic graphical simulation and computerized time study system that has been used to design and evaluate underground production systems for optimizing productivity. Also with the aid of customized software, detailed records on changeable components of underground equipment, including the vendor's name, date installed, operating and maintenance hours, etc., have helped Management to select the best available components for their equipment. The MPASS System, Mine Performance Analysis Simulation System, developed through a cooperative agreement with Freeman United, Ketron Inc., and the U. S. Department of Energy utilizes new methods to analyze and design production systems in underground coal mines. The MPASS System is a menu-driven user oriented system of interactive computer programs, which form five major subsystems. The subsystems: 1. Simulation 2. Time Study 3. Mine Background Reports 4. File Maintenance Subsystem 5. Statistical Analysis Subsystem

Jan 1, 1987

By Carl Rampacek

Laboratory and small-scale continuous pilot-plant investigations made at the Tucson Metallurgy Research Laboratory of the Bureau of Mines have demonstrated that the copper segregation process is applicable to the treatment of oxidized and mixed oxide-sulfide copper ores regardless of the gangue constituents. The process comprises heating the ore to a temperature of 750° C. with small quantities- of sodim chloride and coke to produce metallic copper, which then is recovered by flotation. Tests were made on' 23 copper ores of different types containing 0.8 to 5 percent Cu, .The copper recoveries ranged from 73 to 96 percent in concentrates assaying 10 to 62 percent Cu, depending on the grade and type of ore, The direct operating cost for a 1,000-ton-per-day furnace and flotation plant is estimated at about- $3 per ton of ore.

Jan 1, 1960

By P. Zhang, K. Liu, L. Ou

"The strength and mechanism of Portland cement prepared from stone coal vanadium slag were studied in this paper. Initially, the slag was used as silicon raw materials to prepare clinker. By blending the prepared clinker with gypsum, waste, and fly ash, a series of different grades cement got well prepared. All of performances of the cement were up to the requirements of China’s national standard. The hydration products and microstructure of cement were identified and analyzed by X-ray diffraction and scanning electron microscopy. With the comparison of cement hydration characteristics at different ages, the strength formation mechanism of cement was clarified. The experimental results suggested that adding the fine materials (mainly waste and fly ash) to replace part of clinker would accelerate cement hydration, as it provided additional surfaces for the nucleation and growth of hydration products. And the hydration products were similar to ordinary Portland cement, mainly containing the amorphous calcium silicate hydrates (C-S-H), acicular ettringite (AFt) and portlandite (CH). With hydration time increasing, the hydration products continuously covered the cement particles, resulting in a thicker surface layer. As a result, it gradually condensed into a dense structure block with small pores and smooth surfaces, which led to higher strength. In conclusion, using the vanadium slag to prepare Portland cement can realize the utilization of solid mineral wastes, which will bring huge ecological and economic benefits.INTRODUCTIONWith the development of China’s mining industry, more and more mineral waste residue is discharged every year. These solid wastes cause varieties of resources and environmental problems on people’s living area. While at the same time, the demands of cement are increasing with the remarkable development of the construction industry. Thus, in recent years, utilization of proper solid waste to prepare cement has become an efficient way to deal with the solid mineral wastes problems (Boncukcuoglu, Kocakeri?M, & Tosunoglu, 2002; Simatupang, Hanafi, Purwasasmita, Imran, & Pane, 2012; Tsakiridis, Papadimitriou, Tsivilis, & Koroneos, 2008; Yun, Yong, Choi, Lee, & Lachemi, 2009)."

Jan 1, 2016

By David J. Hatem

Tunnels and underground projects are inherently more risky than vertical projects, which typically utilize more conventional design and construction approaches and are undertaken in the context of relatively ascertained and defined conditions. On tunnel and under-ground projects, there are a host of special risk factors, including unknowns and uncertainties as to the physical and behavioral characteristics of the ground, the inextricable interdependence and necessary interaction of design decisions and construction means and methods with those ground conditions as well as the manner in which risks are allocated among project participants for un-anticipated subsurface conditions. Public-private partnerships (PPP) projects, in their own respects (and independent of any major subsurface component), pose significant risk for all private sector participants. The main driver of owners to procure projects using PPP is financial, as often all, or substantially all, of the design and construction risk are transferred to the private sector consortium, including the design-build (D-B) team. For a concerning number of those public owners, that risk transfer regime includes rather onerous and aggressive contractual terms that allocate to the private sector participants substantially all risks associated with the encountering of unanticipated subsurface conditions. These aggressive risk allocation provisions, while directly impacting project participants upstream of the consulting engineer, have an indirect and corresponding risk intensifying effect upon consulting engineer professional liability exposure. There are many factors that result in increased professional liability exposure for consulting engineers involved in PPP projects. The more prominent and prevalent of those factors fall into the following categories:

By R. M. Westcott

A two-electrode, direct current, slag resistance furnace (SRF) has been constructed and operated to selectively reduce the zinc and lead contents of non-ferrous slags. The experimental SRF is equipped with multiple methods of gas/solids injection for both mixing and reaction. A computer is used to position the electrodes and for data acquisition. A geometric factor correlation was previously developed at Columbia University for calculating the electrical resistance on the basis of furnace geometry and slag conductivity. The experimental SRF was used to test this correlation.

Jan 1, 1994

By Jing Zhang, Qing Xiao, Xulong Liu, Qiuju Li

"Pickling sludge generated from stainless steel production process contains large quantity of Cr, Ni, and Fe. The disposal of and fill sludge directly not only leads to the heavy metal dissolves in the soil and underwater, but also loss value metals. However, the major mineral phases of value metal are hydroxides and there are lots of calcium fluoride and water in the sludge. So the pickling sludge has to be pretreated before reduction-magnetic separation. The TG analysis, reduction reaction and magnetic separation were all used to study the pickling sludge. The result indicated that up to 900°C the total weight loss of pickling sludge was 22.32%. The mass contents of Fe, Cr and Ni in the tailings (non-magnetic) were 4.27%, 0.067% and 0.041% respectively.IntroductionSince 21st century, the stainless steel production in the world has been continuously increasing because of its excellent performance [1]. However, high stainless steel production means a high pickling sludge production. For example, in a stainless steel plant with waste water quantity of 100m3 /h, the production of pickling sludge will exceed 15 Kt/a. Pickling is essential for generating of a homogeneous and corrosion-resistant surface during stainless steel production subsequent process. Pickling of stainless steels is predominantly carried out with an aggressive solution, sulfuric acid H2S04 or composed of nitric acid HN03 and hydrofluoric acid HF [2]. During the pickling process, the pickling acids are recovered through ion exchange and metal ions such as Fe3+, Cr3+ and Ni2+ get into the acids forming the pickling waste water [3]. Then, the pickling waste water is precipitated with lime, forming pickling hydroxide sludge. It is not feasible to recycle or treat the pickling sludge using conventional methods, because the sludge has high contents of calcium fluoride and water but low contents of iron, chromium and nickel. However, it would also pose a potential environmental problem if deposited outdoors over a long term because it contains heavy metals such as Cr and Ni. At present, solidification/stabilization (S/"

Jan 1, 2014

By J. Ouellet

The design of hydrostatic liner for a deep potash mine shaft in Saskatchewan poses tremendous technological challenges. Technology has evolved to a point where one could consider a new innovative approach to hydrostatic liner design. But there is still a place for conventional technologies such as cast iron tubbings. As will be discussed in this paper, improvement to manufacturing process, installation procedures and even new materials can bring this technology to an excellent level of performance. With the spur of new projects in the potash industry of Saskatchewan, the authors worked in various shaft liner designs from the conceptual stage through to the construction phase. They were either directly leading the design work on some of these projects or acting as an external reviewer on others. Most of these shaft liner designs involved cast iron tubbing technology and ground freezing. The major challenge in sinking potash shafts in Saskatchewan is to go through a water-bearing ground formation under high pressure, known as the Blairmore or Manville fm. The only proven stabilizing technology for these formations is ground freezing. For a potash shaft, dry shaft conditions are highly desired, so a fully waterproof hydrostatic liner is required. All the existing potash mine shafts in Saskatchewan, except for two with composite steelconcrete lining, used the cast iron tubbing technology. Two new shaft tubbing liners have been constructed recently, one in the Athabasca Basin and one for a potash mine in Saskatchewan. When the authors began working on these new projects, what became quickly evident is that the technological knowhow for designing and constructing tubbing liners was no longer available within Canada and that the past construction methods used to sink tubbing lined shafts was obsolete. The tubbing liner for the shafts sunk in the sixties were designed either by German or British companies. In both of these countries only few tubbing lined shafts were sunk in last 40 years and the technology used in the sixties was not improved. There are only few countries where tubbing is routinely produced and installed: China, Russia, Ukraine and Poland. Out of these countries Poland is the one where this technology is the most advanced. The authors, working in close collaboration with engineers from Poland, attempted to rebuild this knowledge for the mining industry in Canada. This process involved thorough analysis of old technical reports, literature review and study of current polish design and construction practices as well as site visits of existing shafts. Through actual construction experience, some lessons were learned as well as ideas for improvements. In this paper, the authors will present a succinct review of design and procurement process. But, the practical aspects of the construction and installation methodology will be treated with more emphasis, more specifically the practice leading to good liner performance. Some of the poorly understood technical aspects of tubbing installation will be discussed more thoroughly and some currently accepted myths dispelled.

Aug 1, 2013

Using mines in Canada, Boart Longyear, a leading provider of drilling services and products, has put its Stage 3 Coring Bit to the test and each time the bit has passed the test with great success. After more than a year in the field at a major mine operation in Sudbury, Canada, the Stage3 coring bit broke life records to become recognized as the most productive design in the industry. In addition to the proven advantage seen in regular bit life increases of as much as 300 percent in some cases, the design is quickly being recognized for its cost-saving operational impact. In Sudbury, the mine operation realized actual cash savings of more than C$45,000 within an eight-month period by making the switch to Stage3 bits. For years, the Sudbury Basin team has relied on the Alpha Extended Crown bit with the Express Waterway geometry option, ordering approximately 500 units per year. This 07 COM ECEX configuration performed well in medium-hard, non-abrasive to ultra-hard, non-abrasive formations with an average bit life of 150 m (490 ft). While satisfied with the performance of the Alpha Ex-tended Crown, the team agreed to put the new Alpha Stage3 to the test. Boart Longyear?s field engineers supplied five drill sites with Alpha Stage3 bits in a 07 COM configuration. After thoroughly testing the Stage3, the results were clear. Even with the well-known performance and versatility offered by the previously preferred configuration, the Stage3 set a new standard of bit performance. The new bit maintained its cutting edge for up to three times longer than the Alpha Extended Crown, a significant performance increase when compared to the 07 COM ECEX.

Jan 1, 2009

By D. C. Peck, H. D. M. Cameron, N. M. Halden, L. S. Jobin-Bevans

Abstract-The late Archean Pipestone Lake anorthosite complex (PLAC) is a 0.9 x 17 km sill-like layered intrusion that is part of a suite of coeval megacrystic anorthosite bodies in the Cross Lake region, northwestern Superior Province. Exploration for Ti-V-Fe oxide mineralization and concurrent geological investigations have contributed to a greater understanding of the lithostratigraphy of the PLAC and its oxide mineralization. Mapping and drill core studies have established a laterally continuous igneous stratigraphy comprising six leucogabbro/anorthosite zones and three melagabbro/gabbro zones. Field evidence, including disrupted blocks of layered units, scour contacts, and size-graded and modally-graded layering, suggests younging towards both the northern and the central parts of the complex. A decrease in the anorthite content of the feldspars from An75 in the south to An30 in the north suggests that the magmas become more evolved to the north. Macrorhythmic layering and gross morphological features suggest that the PLAC crystallized from four major influxes of geochemically similar basaltic magmas. The paucity of magmatic erosional features in the PLAC indicates that layering developed in a relatively static magma chamber, so that in-situ crystallization processes are required to account for the observed petrologic diversity. Drilling has confirmed that a significant Ti- V-Fe resource is contained in two of the four discrete mineralized subzones in the PLAC. Textural evidence and the stratiform nature of the oxide-enriched subzones are consistent with a magmatic origin for the oxide mineralization.

Jan 1, 1997

By Z. W. Zhang, Songsong Xu, Jinhui Li, Yun Zou, Yu Zhao

High strength low alloy (HSLA) steels with high strength, high toughness, good corrosion resistance and weldability, can be widely used in shipbuilding, automobile, construction, bridging industry, etc. The microstructure evolution and mechanical properties can be influenced by thermomechanical processing. In this study, themomechanical processing is optimized to control the matrix microstructure and nano-scale precipitates in the matrix simultaneously. It is found that the low-temperature toughness and ductility of the steels are significantly the matrix microstructure during enhancing the strength by introducing the nano-scale precipitates. The effects of alloying elements on the microstructure evolution and nano-scale precipitation are also discussed.

Jan 1, 2016

By Zhengya Lu, F. Lawson

The surface tensions of lead and lead alloys with very low concentrations of silver, tin and copper were measured by the sessile-drop method. The enrichment of silver and tin in the surface of liquid lead alloys at temperatures close to the freezing-point of lead was confirmed, which may explain the unusual behaviour of small amounts of silver and tin in lead bulllion during the sulphur-drossing step of the refining process. From the limited data available copper also appears to concentrate at the surface of the liquid alloy

Dec 1, 1991

By T. E. Gray

This report describes the preparation characteristics of the significant coalbeds in Harrison County, W. Va. It is one in a series of Federal Bureau of Mines reports planned to determine coals suitable for the production of metallurgical coke, either as mined or after beneficiation. Over 6.5 million tons of coal was produced in Harrison County, W. Va., in 1958, of which over 3.7 million tons was cleaned mechanically in seven preparation plants. All of the coal cleaned was from the Pittsburgh bed. It has been estimated that more than 1,816 million tons of coal remains in the county in beds 12 inches or more thick. The Pittsburgh and Redstone beds were selected by the Bureau for a study based on current production rates and estimated minable reserves. Sample locations were selected following a study of the literature, conferences with mining engineers and mining company officials in the field, and examination of the available sites. Six samples were collected from the Pittsburgh bed, and three samples came from the Redstone bed, Float-and-sink tests of the samples collected from the Pittsburgh and Redstone beds showed that neither coal could be upgraded to a metallurgical fuel under the standards set up for this study, even after intensive preparation. Finer crushing of the samples moderately increased the yields and slightly reduced both the ash and the sulfur contents in the 1.30-specific-gravity float fractions. Finer crushing slightly decreased the yields in the 1.58-specific-gravity float fractions, whereas it reduced the sulfur content 0.11 percent for the Redstone sample and 0.46 for the Pittsburgh sample.

Jan 1, 1961

By Mustafa Kumral, Mehmet Balci

Strategic mine planning centers on solving cut-off grade selection, capacity planning, and block sequencing. Even though significant knowledge has been accumulated on mine planning over the last decades, there is still potential to add value to mineral sourcing by addressing various aspects. To this end, this paper addresses two issues. The effects of (1) grade/metal distribution within a mineral deposit and (2) the economies of scale (EoS) are explored in cut-off grade selection and capacity planning. In doing so, the interdependency between cut-off grade selection and capacity planning is also considered. A case study is implemented on a metallic deposit whose grade distribution exhibits lognormal distribution to detect if grade/ metal distribution influences cut-off grade selection. Also, based on the same ore tonnage and metal quantity, six different datasets are generated with different shape and scale factors. The research outcomes indicate that deposits with lower shape and scale factors of lognormal distribution are more sensitive to metal price and discount rate changes because slight cut-off grade variations significantly change net present value (NPV). While the NPV of the deposit with the largest shape factor is $3,208,112,841 with a cut-off grade of 0.058 oz/tonne, the NPV of the deposit with the smallest shape factor is $93,617,240 with a cut-off grade of 0.027 oz/tonne. Furthermore, the case study is directed to investigate the effect of EoS on a project’s value, with a specific emphasis on the ratio of variable cost to total cost (capacity factor). Two different regression analyses are conducted based on the proposed model for optimal capacity planning and cut-off grade selection, respectively. In the first one, the absolute standardized beta values for EoS of mining and mineral processing costs are 0.736 and 0.425, meaning that capacity planning is highly sensitive to the EoS of mining and mineral processing operating costs. Meanwhile, the absolute standardized beta value for grade variability is 0.054 which means that the effects of grade variability and metal distribution are almost negligible for capacity planning. However, EoS is the most critical variable for capacity optimization. In the second regression analysis, the standardized beta values for grade variability and EoS of mineral processing operating cost are 0.573 and 0.522, so their effects on cut-off grade selection become vital.

Apr 29, 2024

By M. J. Ferrante

The Bureau of Mines determined the enthalpies of Ni3S2 relative to 298.15 K to provide new thermodynamic data for advancement of mineral science and technology. Enthalpies were measured with a copper-block calorimeter from 298.15 to 1,197 K. A solid-solid transition was found at 834±1 K, with an isothermal heat absorption of 13.32 kcal/mol. The temperature of this solid-solid transition was accurately measured by differential scanning calorimetry. Because Ni3S2 does not melt congruently, the heat of fusion of 4.70 kcal/mol was obtained by extrapolation of enthalpy measurements from the solid and liquid phases to approximately 1,064 K. Tabulated values are given for the relative standard enthalpy, heat capacity, entropy, and Gibbs energy function between 298.15 and 1,800 K. Enthalpies are also given in equation form and combined with data from the literature to derive values of standard enthalpies of formation and Gibbs energies of formation. Similar calculations were made for the reaction of crystalline and liquid nickel with gaseous diatomic sulfur for Ni3S-2(c, l).

Jan 1, 1982

By C. Patrick

Longwall face-to-face transfers can cost over $100 per minute in lost production potential and $100,000 for personnel and supplies. Such high cost makes extensive planning and control of the transfer process a critical necessity for the economic feasibility of longwall operations. This paper reports operations research techniques used for the analysis and modeling of longwall face-to-face transfers. Transfer data has been collected from companies who operate over 30% of the total U.S. longwall faces. Comprehensive sequence networks of existing longwall transfers were developed; simulation models of transfers under varying conditions were generated; and, the economics of general transfers and time-cost tradeoffs in the transfer procedure were investigated.

Jan 1, 1993

By Brent A. Elliott, J. Richard Kyle

This article reviews the production trends of industrial minerals since 2000 for Texas, the leading U.S. producing state of industrial minerals with a total value of $5.2 billion in 2017, equivalent to 6.9 percent of all U.S. minerals value. Most current Texas industrial-mineral value comes from the production of cement, crushed stone, industrial sand, and construction sand and gravel. Construction material consumption is concentrated in the 25 metropolitan areas of the state, with production of industrial minerals in nearby counties. With Texas’ population projected to reach 50 million by 2050, continuing in-state development and production of industrial minerals will be required to meet in-state and regional demand. Texas’ most rapidly growing production of industrial minerals is industrial sand to supply proppants for multiple unconventional petroleum plays. Texas’ favorable geology and economic factors provide opportunities for the identification and development of new industrial-mineral production sites. Repurposing of former industrial-mineral production sites for post-production development likely will increase as efficient land use evolves. Understanding the geologic, economic and societal framework of industrial-mineral resources will facilitate more informed decisions about the complex issues that the region will face, including effects of sea-level rise on coastal infrastructure.

The grade (or value) to volume relationship which constitutes a target orebody is used to show that the concentration of diamonds in an economic deposit may be as low as O.Olg/t. Diamond valuations from an Indonesian deposit demonstrate that the largest 5% of the diamonds in the deposit contributed 25% of the mass of diamonds recovered and 70% of the value from the ore. The need to consider the large stone content and the probability of recovery is used to estimate that the sampling density is required to be as high as 4-10,000ppm for a VLC deposit. This is compared with an acceptable sampling density for a bauxite deposit of 700ppb. A case history of the discovery of a diamond bearing paleo-channel in the Ellendale field in Western Australia illustrates that the sampling task becomes impractical. It requires an excavation in excess of 300,000 bcm of material to prove a 5M hem ore reserve. The conclusion is reached that setting up a small scale mining operation is an appropriate method of proving such an ore reserve and that the Code of Reporting should allow a category of "Mineable Resource" to cover such a situation.

Jan 1, 1990

By Kazutoshi Haga, Batnasan Altansukh, Atsushi Shibayama

Results of flotation process combined with atmospheric leaching and high pressure leaching for recovery of copper from low-grade silicate-copper ore have been presented in this study. The low-grade copper ore contains a small amount of copper (0.42 mass %), iron (4.6 mass %), and silicon (38.3 mass%) and among many other metals (Al, Ca, K, Mg, Na, Ti and S). The main mineralogical constituents of the copper ore are calcium aluminosilicate (Ca(Al2Si2O8), amesite (Mg2Al2SiO5(OH)4) and gypsum (CaSO4×H2O), and quartz (SiO2) as resulted from the alteration of an igneous rock. This study has shown that about 92 % of copper can be recovered with a maximum copper grade of 4.2 mass% in a froth after 15 minutes of flotation at pH 8.5 when used potassium amyl xanthate as a collector, MIBC and Dow-froth 250 as frothers and calcium hydroxide as a pH adjuster. The images of bubbles in the cell during flotation process were recorded using a high-speed camera. The froth concentrate with average copper grade of 2.0 mass% was further processed by atmospheric leaching with a solution of sulphuric acid and hydrochloric acid, respectively and high pressure leaching with sulphuric acid solution. As a result, leaching rate of copper reached about 60 % in an atmospheric leaching with sulphuric and hydrochloric acid respectively, whereas the rate can reach more than 70 % by autoclave leaching at high pressure under the controlled condition. A process to recover of copper from its low-grade ore can be developed by optimization of flotation combined with acid leaching.

Jan 1, 2014

By S. Y. Tan

The thermal stability of fully silicided NiSi with arsenic doping on silicon was investigated. The aims of the work were to investigate the Ni silicide phase-related issues associated with arsenic dopant and thermal annealing on Ni-FUSI/HfO2/Si and Ni-FUSI/HfSiO/Si gate stacks. It was found that arsenic-incorporation demonstrated some improvement in both morphology and phase stability of nickel silicided films at high processing temperatures regardless underlying gate dielectrics. The correlations of Ni-Si phase transformation and arsenic doapnt with their electrical and physical changes were established by sheet resistance measurements, X-ray diffraction (XRD), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) analysis. Furthermore, the modulation of the work function (WF) of Ni fully silicided gates by arsenic impurity is presented, comparing the effects of dopant (As) on the WF and silicide phases (NiSi and NiSi2). It confirmed that the work function of NiSi can be tuned by implanting arsenic dopant, but it ineffective for NiSi2 phase.

Jan 1, 2010