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By B. G. D. Smart

An understanding of the nature of yield zones surrounding coal mine excavations is fundamental to the design of mine support systems. Various methods have been designed for investigation of underground rock masses and an extensometric technique, the Magnetic Rod Extensometer, has been developed to overcome inherent design limitations in existing equipment of this type. This paper refers to the prototype form of the extensometer and details changes designed to overcome a variety of drawbacks indicated by routine use of the equipment. The principal change has been one of manual to computerised data acquisition and presentation in the laboratory phase of the system. This has dramatically reduced the time taken to process underground measurements and produce numerical and graphical results. The revised Magnetic Rod Extensometer represents an integrated instrumentation system that combines speed and accuracy in all areas of data handling.

Jan 1, 1984

By K. S. Liddell, L. A. Smith

"Kell is a hydrometallurgical treatment option for the recovery of platinum group metals (PGMs), gold, silver, and base metals from flotation concentrates to refined products on site. The process is cyanidefree, while eliminating emissions of sulphur dioxide, arsenic trioxide, and other toxic species often emitted by smelters and roasters. Kell has been tested on a range of concentrates, including PGMs (UG2, Merensky, Platreef, Great Dyke, Great Lakes, Lake Superior and others), refractory gold-silver, coppergold, and polymetallic concentrates. High extraction efficiencies (>95%) are achieved for value metals (Pt, Pd, Rh, Au, Ag, Ni, Cu, Co) and secondary metals (Sb, Zn, Pb, and others). Studies comparing Kell with smelter-refining show economic benefits: capex 18–33% of smelting; opex 51–66%; electricity consumption 13–46%; and environmental benefits: greenhouse gas emissions 57–61% of smelting, acidification 5–27%, human toxicity 37–62%, and freshwater ecotoxicity 43–55% of smelting. Synergies for Kell plants alongside smelter-refineries include utilization of recovered acid from sulphur abatement systems and excess capacity in precious metal refineries. Kell is unconstrained by concentrate grade and impurities, allowing the co-location of Kell plants for treatment of non-smeltable concentrates alongside existing smelters.Kell has been demonstrated in a nine-week integrated pilot campaign at 1:1000 scale, supporting a bankable feasibility study for a 110 000 t/a plant treating a UG2-Merensky concentrate at Pilanesberg Platinum Mine (PPM), owned by Sedibelo Platinum Ltd, which has along with South African Industrial Development Corporation (IDC), invested in Kell. Zimbabwean Mining Development Corporation (ZMDC) has signed a Memorandum of Agreement (MOA) with KellTech for a centralized PGM concentrate processing plant."

Jun 1, 2019

By B. Soundara, A. Suganya, S. Selvakumar

"Expansive soils have a potential for shrinkage or swelling under changing moisture content. Attempts were made to reduce the swelling potential of expansive soils with conventional additives such as lime, cement, etc. and non-conventional additives such as industrial wastes. In this research an attempt is made to study the feasibility of using granulated waste expanded polystyrene (EPS) as an additive to expansive soil to control swelling. To investigate the effect of mixing waste EPS granules with expansive clays, three expansive soils with different plasticity index were manufactured in the laboratory by mixing sand with sodium bentonite of various proportions. A series of standard proctor test, California bearing ratio (CBR) test, one dimensional free swell and swell pressure tests were performed on these soils. Test results show that the inclusion of EPS granules significantly reduces the percent swell and swelling pressure when subjected to one-dimensional free swell conditions. The dry density and CBR values decrease with increase in EPS content and increased plasticity of the soil.INTRODUCTIONExpansive soils cover an area of about 257 Million hectares on the earth’s surface (Dudal et al. 1965). In India, the area covered by expansive soils is nearly 20 percent of the total area (Mohan et al. 1961). Movement is usually in an uneven pattern and of such a magnitude as to cause extensive damage to various structures, especially lightly loaded structures or pavements (Chen 1975). Stabilization is one of the methods of treating the expansive soils to make them fit for civil engineering purposes. The variety of stabilizers may be broadly divided into three groups (Petry et al. 2002): (a) traditional stabilizers (lime, cement etc.), (b) by-product stabilizers (fly ash, quarry dust, phosphor-gypsum, slag etc.) and (c) non-traditional stabilizers (sulfonated oils, potassium compounds, polymer, enzymes, ammonium chlorides etc.). Apart from these, a number of other ground improvement techniques such as sand cushion technique (Satyanarayana 1966); cohesive nonswelling (CNS) layer technique (Katti 1978) were adopted for the stabilization of expansive soils. Expanded polystyrene (EPS) is a polymeric foam normally available in white colour and is a wellknown packaging material. The geotechnical specialists recognize EPS as the most commonly used geofoam material, a type of cellular geosynthetic which has been in consistent use in geotechnical applications since the early 1960s (Horvath 1995). EPS has very low thermal conductivity and nearly 98% of the volume is air (Lye et al. 2002). EPS has many exceptional properties such as being lightweight, thermal insulating, shock-absorbing and having low-water pick-up, etc. EPS find its applications in geotechnical engineering as light weight fills in the form of blocks (Refsdal 1985, Karpurapu et al. 1992, Zou 2001, Ikizler et al. 2008). EPS can be used as compressible inclusion and as a vibration damper (Horvath, 1994&1995). EPS is also used in lightweight concrete owing to its lightweight, excellent heat preservation and sound insulation properties (Ravindrarajah et al. 1994; Miledet al. 2004 and Babu et al. 2005). Waste EPS granules have been used in with horticultural soils to improve a number of soil characteristics like improving drainage, lightening heavy soils and improving water uptake capacity of soils (Scheirs 1998). Furthermore, it was also used as sub-base materials for pavements and railway track beds (Hanna 1978; Duskov1996), construction materials for floating marine structures and fenders in offshore oil platforms (Bagon et al. 1976), sea beds and sea fences; as an energy absorbing material for buried military structures, (Perry et al. 1991)."

Jan 1, 2017

By Robert I. Fujimoto

The work described was conducted to develop standards for the application of wire rope clips on wire rope. These standards include optimum number of clips and clip nut torques for wire rope sizes 1/4 through 2-1/4 inches, when used for forming an eye attachment in wire rope. Wire rope test specimens with clip attachments were load tested on tensile testing machines to determine an effective combination of clip nut torques and number of clips for each size of wire rope to develop efficiencies above 90 percent of the catalog ultimate rope strength.

Jan 1, 1973

By Michael Harris, David Mosch

The numerous small high grade gold and silver deposits of the Front Range Mineral Belt have been uneconomical because of the high costs of mill construction, transportation, and smeltering. Processing of these ores must be simple, cheap, with satisfactory recoveries, and be environmentally acceptable. Vat leach with direct electrolytic recovery satisfies these parameters. A battery of testing was conducted utilizing bottle and bucket tests. A five ton vat leach with direct electrolytic recovery gave excellent results while a five ton heap leach proved impractical due to channeling.

Jan 1, 1987

By L. B. Clarke

The optimal maintenance and control of the air flow and pressure distribution in a mine network are achieved by the correct positioning of the mine fans and regulators within the mine ventilation circuit. The principal considerations are the location of the main and underground fans or regulators and the attendant control of mine leakage. Air flow control is achieved by either passive or active regulation. Passive regulation adds resistance, usually in the form of a regulating door. Active regulation adds pressure sources in the form of underground booster fans. Ventilation engineers are increasingly turning to analytical tools to assist them in the design and operation of ventilation systems. The application of computer methods, formal optimisation methods and numerical solution methods is outlined

Jul 1, 1996

By D Chappell

Coromandel Peninsula gold mineralisation has an epithermal style which involves extensive alteration of host rocks and addition of pyrite over large volumes of rock. These altered rocks therefore have high potential for generating acid rock drainage. Natural acid groundwater discharges occur in altered rocks, but not in propylitically altered rock. There is little calcite available in mineralised rocks to neutralise this acid. In contrast, the mesothermal veins of the Otago Schist cause little alteration of the host rock, and that alteration has similar mineralogy to the host rock. Calcite is a common mineral in host and mineralised zones, and sulphides are generally subordinate. Hence acidification of Otago rocks is unlikely. This lack of acidification in Otago facilitates arsenic mobility in solution, up to hundreds of ppm. Arsenic is insoluble under acidic conditions in the Coromandel. Base metals are soluble under acidic conditions of the Coromandel, but they are immobilised by adsorption on to the widespread clay minerals where the solutions are neutralised. Base metals are generally immobile in Otago, but when they are mobilised, adsorption is less effectiveas an attenuation mechanism because clay minerals are rare.

Jan 1, 1998

By G. Couture, J. -F. Dubé, F. Letarte-Lavoie

"The Xstrata Nickel Raglan concentrator, located in Quebec’s Nunavik region, has been in operation since 1997. Originally designed to process 800,000 tonnes per year of high-grade nickel ore, the plant’s current capacity is 1.3 million tonnes per year due to various optimization projects. In 2011 and 2012, the Metallurgical group, with assistance from BBA, updated and optimized the variables affecting SAG throughput in order to optimize process stability while maintaining maximum plant throughput. This project consisted of reviewing the control strategy and completely updating the pre-existing Fuzzy Logic controller. This paper describes the successful update of the controller including a complete revision of control rules, a new process control strategy and the integration of new process variables, most notably mill rotational speed. It will also show how this new approach has provided a simple and robust way of delivering both an increase in throughput while reducing process variability.INTRODUCTIONThe Xstrata Nickel Raglan Mine concentrator is located in Northern Quebec along the 62th parallel. It has been in operation since 1997 and was originally designed to treat 800,000 tonnes of ore annually. The Raglan Agreement held with the Makivik Corporation and the Inuit communities limits the annual tonnage of ore that can be processed at 1.32 million tonnes.The ore is processed in a 24 foot variable speed, semi-autogenous grinding mill (SAG). The conversion from Autogenous Grinding (AG) to SAG was completed in 2006. Before the ore is processed by the SAG, its size is analyzed by a Wipfrag camera that provides a granulometry estimate. A cone crusher reduces the SAG’s discharge screen’s oversize material. A 14 foot diameter ball mill ensures final grinding before the flotation stage.Many control strategies were used at the SAG over the past few years. Fuzzy Logic was first used in 2007 in order to control tonnage feed to the SAG. This first version only measured the value of the variables without taking into account their rate of change. Revisions were made over the course of the last few years to improve controller performance. Other variables were added such as slurry density and crusher Closed Side Setting (CSS). The previous revision of the Fuzzy Logic was done in 2009 with a review of the rules only."

Jan 1, 2013

By Carl Sunderman, Steve Signer

Researchers at the National Institute for Occupational Safety and Health (NIOSH) have developed several new tools for evaluating roof support performance. A miniature data acquisition system (MIDAS) was developed that can collect readings from up to 16 strain gauges at regular time intervals and store the readings for later retrieval. Three LED lights change from green to yellow, then red, based on the reading levels and/or rates of change of rock movement. This feature can be used to warn miners of rock instabilities. The system can be used with any strain-gauged support (resin bolt, friction bolt, cable bolt) or with a newly developed rock strain strip (ROSS) developed by NIOSH to measure rock strain. A ROSS is grouted in a hole drilled adjacent to the rock support to be evaluated; the deformed shape of the ROSS provides anchorage on either side of the strain gauges. Data from both laboratory tests and field evaluations are presented that describe the capabilities of both the MIDAS and ROSS instruments.

By Dave Bulled, Khiratt Husain

"The use of High Pressure Grinding Rolls is gaining significant interest as a replacement for SAG milling in the comminution of hard rock ores because of the potential for reduced costs in terms of energy and grinding ball consumption. Estimation of expected energy consumption for fullscale operations has conventionally involved the testing of a few fairly large samples in pilot scale HPGRs. This paper describes the development of a small-scale batch test method for determining a work index for HPGR of a large number of samples that can be used to show the variability of the ore as an integral part of a geometallurgical approach to circuit design and production forecasting.The test equipment that was developed comprises a hydraulic press with adjustable pressure operating on small batches of ore in a locked cycle test procedure. A work index measurement was determined that links the specific energy consumed in the test to the breakage achieved such that the index can be used to predict comminution energy requirements.The measurements were calibrated against laboratory scale HPGR equipment to develop a model for design and forecasting that includes crushers, HPGRs and ball mills in a complete comminution circuit.INTRODUCTIONEstimation of the expected energy consumption for full-scale HPGR operations has conventionally involved the testing of a few fairly large samples in laboratory and pilot scale machines (Danilkewich, 2006). With the financial input of five mining corporations, SGS Lakefield Research has developed a small scale test capable of providing relevant information on the variability of energy consumption and size reduction from drill core samples. It is our intention that the values measured in the test will be scaled up, through benchmark comparison with pilot sized and full sized HPGR units, to allow plant design and throughput forecast on a block by block basis of the mine plan using a new CEET program. CEET® (an acronym for Comminution Economic Evaluation Tool) is an advanced grinding design and performance predicting tool that uses energy relationships to model the performance of SAG / Ball mill circuits."

Jan 1, 2008

During a programme to determine the suitability of the UK site for deep disposal of radioactive wastes, geostatistical methods were used to characterise rock heterogeneity on the basis of seismic and wireline acoustic-impedance data. The data were analysed to yield semi-variogram models that quantified the three-dimensional spatial heterogeneity of acoustic impedance. These models were reconciled with geological interpretations of the area and used to generate simulations of acoustic impedance, with wireline acoustic impedance as conditioning data. The three-dimensional simulated images were compared with actual seismic acoustic impedance. The variography confirmed a vertical zoning effect in the Borrowdale Volcanics, showing that it is caused by preferential clusters of high acoustic impedance values corresponding to regions of relatively low porosity. The method provided realistic three-dimensional models from sparse, one-dimensional wireline data

Jun 19, 1905

By V. A. Melezhik, A. H. Green, L. N. Grinenko

Finally, a theoretical model is constructed that takes

Aug 1, 1994

By S. R. Amos, N. O. Lotter, A. L. Hannaford, J. F. Oliveira, D. W. Broughton

"Ivanplats Ltd appointed Xstrata Process Support to perform the flowsheeting development work for their hypogene and supergene geomet units of the Kamoa Copper deposit, located in the Democratic Republic of the Congo. Through systematic flowsheet development using modern Process Mineralogy, the optimised milestone flowsheet delivered a saleable concentrate grade of 32.8% Cu at 85.4% recovery with hypogene ore, and a saleable concentrate grade of 45.1% Cu at a recovery of 83.4% for supergene ore. The significant value of this development is that a single flowsheet will treat both hypogene and supergene ores and produce saleable concentrates. Further work to advance the flowsheet performance has been identified for investigation in the near future.INTRODUCTIONLocation and Description of the Kamoa DepositThe Kamoa copper resource is located some 40 km west of the city of Kolwezi, in the south west of the Katanga Province of the Democratic Republic of the Congo, in the region of Central Africa. Drilling at Kamoa in 2008-2009 had discovered laterally continuous, sediment-hosted, high-grade stratiform copper mineralisation in a newly discovered copper district that forms a previously unrecognised western extension of the famous Central African Copperbelt – which hosts such world-class deposits as Kolwezi, Tenke-Fungurume, Konkola and Nchanga. This discovery showed that the western end of the Copperbelt in the Congo does not terminate at Kolwezi (Friedland & Broughton, 2009). The resource contains hypogene and supergene geomet units with a transitional zone located inbetween the (upper) supergene and the (lower) hypogene. In the hypogene unit, the major copper sulphides are bornite, chalcopyrite and chalcocite, whilst in the supergene, the sequence is led by chalcocite, then bornite, and finally chalcopyrite. Covellite is present in both units as a minor copper sulphide. Both geomet units will be mined and treated in one concentrator, either as blends or as campaigns."

Jan 1, 2013

By O. J. C. Runnalls

"Canada became the world's largest uranium producer in 1984. That leadership position is likely to be maintained for many years into the future because of a firm production base, many undeveloped known deposits with commercial promise, and a large geologicalpotential for new discoveries.There are some uncertainties on the horizon, principally because of restrictive actions in process within the U.S.A., which are aimed at preserving a deteriorating domestic uranium industry. Should such actions result in import restrictions, for example, there would be a negative effect on foreign producers at least in the short term. Canada may avoid such difficulties under a tentative U.S.-Canada free-trade agreement where restrictions on the import of Canadian uranium into the United States would be eliminated. Over the longer term, demand for Canada's uranium resources will grow because of the foreseen growth in the world's installed nuclear power capacity. IntroductionSince the phenomenon of nuclear fission was discovered in 1938, the utilization of uranium has grown substantially. Initially, the principal use for uranium was in the production of nuclear weapons. However, once civilian nuclear power reactors began to be built in the 1950s, an increasing fraction of uranium output was directed to the production of fuel elements for use in electricity generating stations.The cumulative uranium production by those countries in the World Outside Centrally-Planned-Economies Areas, WOCA, during the period 1938 to 1985 exceeded 800 000 tonnes of uranium. Some 60% of that was mined in the United States and Canada, as indicated in Figure 1. In 1986, nearly 80% of WOCA output came from five countries, Canada, United States, South Africa, Australia, and Namibia, as indicated in Table 1 and illustrated in Figure 2.During the past decade the world annual consumption of nuclear energy has more than tripled (Fig. 3). As of December 31, 1986, the world total of nuclear power reactors had reached 394 with a total net capacity of 270 GWe. The thermal output from nuclear power plants in 1985 exceeded 60% of the energy contained in all of the oil produced that year in the Middle East. Thus, nuclear power has already become an important component in the world energy supply picture."

Jan 1, 1988

By Benedicto Hadad Cintra

In an inflationary environment the need for reduced cost is a daily concern of all industries. The Du Pont do Brasil "Expanded Pattern" method has proven to be an extremely effective means of reducing costs in mining, quarrying and construction operations. Over the past years much emphasis was placed on rectangular drilling patterns where the burdens are less than the spacing. The Expanded Pattern method combining rectangular and staggered patterns, was implemented in 1971 in Brazil after extensive trials in close collaboration with numerous explosives users and Du Pont do Brasil Technical Services Engineers. The best multiple row spacing-to-burden ratio (S/B) was demonstrated to be in the 2 to 5 range and the effective spacing to burden ratio (Se/Be) was found to vary from 5 to 11. These ratios are for the interior of the blast pattern and do not hold true along the front row of holes. Geological rock properties, hole diameter and inclination, explosives energy and loading density, explosives characteristics, blast pattern geometry, bench height and delay patterns along with type and size of digging, hauling and crushing equipment must all be evaluated for each and every operation. The integration of these interrelated parameters, together with sound blasting practices are the basis for the Expanded Pattern method. Color slides and documented case histories will be presented.

Jan 1, 1985

By Emerson de Andrade Monteiro

As ligas de titânio ao Nióbio apresentam grande potencial de desenvolvimento graças a excelentes combinações de propriedades. O tratamento termomecânico a elas conferido é importante para atingir as propriedades desejadas. O presente estudo tem como objetivo avaliar o efeito da conformação mecânica nas propriedades da liga Ti42Nb forjada a frio com 80% de encruamento e seguido de envelhecimento. Foram realizados ensaios de tração, medidas de dureza, metalografia e microscopia das superfícies de fratura. Foi possível observar que a liga Ti42Nb apresentou maior dureza e consequentemente maior resistência após o envelhecimento.

Aug 16, 2017

By G. Danko

MULTIFLUX, a new thermal, hydrologic, and airflow model and software is being developed to solve the flow of heat, moisture, and air in and around an underground opening. MULTIFLUX couples two distinct domains that are solved separately first and re-coupled as an iterative task: (1) the rockmass, and (2) the airway. The airway is solved with a lumped-parameter Computational Fluid Dynamic (CFD) module which is an embedded part of the MULTIFLUX code. The CFD model includes convection, conduction, and radiation for heat, as well as convection and diffusion for moisture transport in an air-filled opening. The CFD model also solves for the airflow field. The surrounding rockmass model may be from any analytical solution, or from a complex thermal-hydrologic numerical model such as NUFT or TOUGH2. The rockmass model is interfaced to MULTIFLUX using a novel technique called Numerical Transport Code Functionalization (NTCF). The method provides fast convergence on a personal computer platform. The paper reports the results of MULTIFLUX simulations for a mine drift, comparing calculations with a known mine climate software, CLIMSIM, and with measured data. Through this validation example, the performance of MULTIFLUX is demonstrated. The results show excellent agreement due to the use of realistic modeling assumptions and boundary conditions.

Jan 1, 2009

By Russell R. Trengove

The largest potential reserves of manganese in Nevada are in the Pioche district. To date, these large reserves of 10-to l2-percent manganese cannot be upgraded economically. Other large, low-grade deposits, such as the Virgin River and Boulder City deposits in Clark County, cannot be considered immediate sources of manganese. Reserves of the principal manganese deposits in Nevada, based on the most reliable estimates, total about 17 million tons analyzing 7.6 to 13.6 percent manganese. Most of the deposits are of a type that cannot be prospected systematically but have been prospected and developed in the course of productive mining operations. To realize production from low-grade deposits that are amenable to concentration, a ready market must be provided. Thus far, Government stockpiles have been the major outlet for these low-grade ores. Research and experimentation over a period of years have led to development of several processes technologically applicable to these low-grade ore bodies, but their economics is not sufficient to allow competition with imported ores on the open market.

Jan 1, 1959

Electrochemical Behaviour of Massive Chaclopyrite Bioleached Electrodes in Presence of Acidithiobacillus ferrooxidans and Acidithiobacillus caldus In this work, the monitoring of bacterial and chemical dissolution of massive chaclopyrite was evaluated using cyclic voltammetry (CV); the mineral surface was examined using scanning electron microscopy (SEM) and the elements were examined by Energy Dispersive X-ray Analysis (EDAX). The electrolyte employed for the electrochemical tests was the medium used to bioleaching the electrodes (3.0 g/L (NH4)2+SO4, 0.5 g/L K2HPO4, 0.5 g/L MgSO4+7H2O and 0.1 g/L Ca(NO3)2).The results showed differences in voltagramms carried out by Acidithiobacillus ferrooxidans and Acidithiobacillus caldus: In bioleached electrodes tested in the presence of Acidithiobacillus ferrooxidans, the anodic and cathodic current signals were larger than with Acidithiobacillus caldus. The analysis of CV results allowed attributing the different peaks observed in both the direct and reverse potential scanning to the oxidation of chaclopyrite to a secondary copper mineral (bornite, chalcocite and covellite) and its reduction via different non stoichiometric copper sulphides intermediaries. Surface evidences were observed by SEM, and chemical elements evidences were also investigated by EDAX.

Sep 13, 2010

By M. van Schoor

Coal remains South Africa?s most abundant and cheapest source of energy, and there is an ever-increasing necessity for optimal and safe extraction of the remaining reserves. Increasing focus on cost-effective mining and zero harm to the environment and miners has resulted in a shift in attitude towards the application of geophysics in local coal mining and exploration. Furthermore, technological advances have contributed to geophysics being embraced more readily by the coal mining industry, compared to a decade or two ago. Predictably, the growing interest in geophysical technologies has also created a need for education and training in the basic principles and application of geophysical methods, as local coal mining companies generally do not have in-house geophysicists. Consequently, the Coaltech Research Organisation?s Geology and Geophysics working group forum compiled a textbook aimed at addressing this need: to produce a guide for applying geophysics to coal mining problems in South Africa. The target audience for such a book would be coal geologists, mine surveyors, mine planners, and other mining staff with limited or no geophysics background. This paper provides a very brief overview of the book by summarizing key sections and selected examples. In doing so, the value of geophysics to solving a range of coal mining and exploration problems is highlighted.

Jan 1, 2014