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Mining One (M1) is often challenged with the task of evaluating deposits considering open cut and/or underground (UG) mining methods. In many near surface deposits a combination of both methods results in the optimum economic means of exploitation. As common as it is to have open pit mines eventually develop into underground mines, theory associated with determining the optimum underground/open pit interface location continues to be subject to refinement. With recent developments in underground software packages, the generation of rudimentary underground mining stopes from basic economic inputs is not only fast, it provides a practical underground mining solution. The determination of the open pit/underground interface is not new to Gemcom's Whittle 4X (Whittle). However, its solution has only ever claimed to be indicative, mainly due the rudimentary nature of how Whittle represents any potential underground mining. The efficient generation of the aforementioned underground mining solution has provided mining engineers with a unique opportunity. Underground mining can now be represented within the Whittle environment to allow the open pit/underground mining scenario to be modelled with increased accuracy. Providing Whittle with the ability to now consider mineable underground stopes combined with the consideration of time value of money (discounting), has delivered a solution with higher credibility than ever before.This paper will elaborate on the potential value gains associated with improved accuracies in the modelling of any potential underground mining in the Whittle environment. Furthermore, it will explain the importance of incorporating time value of money in the optimisation process to provide a consistent solution through to pit selection and final analysis.

Dec 6, 2010

By Wang Yongjia, Steven L. Crouch

This paper describes a numerical method for computing time- dependent displacements and stresses in linear viscoelastic media. For such materials, the correspondence principle can be used to obtain the time-dependent solution directly from the solution to an associated elastic problem in Laplace transform space. The elastic solution, in turn, can easily be obtained by boundary element methods. The work presented in this paper is based on the displacement discontinuity method, adapted for the case in which the region of interest consists of two half-planes bonded together. A practical example of the method is given for a problem involving a panel of rooms and pillars in a thick layer of salt that is overlain by limestone. Viscoelastic behavior of the salt causes time-dependent displacements and stresses in both rock types.

Jan 1, 1982

URANIUM is commonly recovered by either column ion exchange (IX) or basket ion exchange (RIP) from solutions resulting from sulfuric acid leaching of uranium-bearing ores. In both operations a solid state ion exchanging resin is used, the major difference being that practically clear uranium pregnant solutions are required for passage through resin columns whereas in RIP, leach slurries from which only the sands have been removed are caused to flow through ion exchanging resins contained in baskets. The solvent extraction process as used for recovering uranium from acid leach solutions is also an ion exchanging process, but one in which the ion exchanging medium is a liquid rather than a solid state resin. For this reason, SX is often referred to as liquid ion exchange, although liquid- liquid extraction is probably more accurate. Uranium in its sulfuric acid leach solutions exists in an equilibrium that may be visualized as follows: [ ] Because of an equilibrium of this nature, uranium may be recovered on either cation exchanging or anion exchanging resins and then concentrated during the resin eluting operation. Similarly, solvent extraction processes may utilize either anion ex- changing or cation exchanging liquid organic phases, which capture the uranium and permit its subsequent concentration when the organic phase is stripped.

Jan 9, 1957

By J. Shibata

The recovery process of valuable metals, such as Ll, Mn, Ni and Cr from a waste lithium battery was developed n this study. Lithium and Mn are selectively leached from the battery by using dilute mineral acid. Main part of the battery comprises stainless steel, and Fe, Ni and Cr are easily leached by the mixture of dilute HCl and HNO3 Lithium and Mn are precipitated as metal carbonates from the? individual leached solution with sodium carbonate solution. The solution containing Fe,Ni and Cr Is treated by solvent extraction to separate NI and Cr from the leached solution. The experiments are carried out for leaching and separation steps. According to the experimental results, the flow. sheet for a recovery process of valuable metals from a waste lithium battery has been established.

Jan 1, 1995

By J. Bigu

A theoretical radiation mine model, suitable for underground uranium nines, has been investigated. In this model, the rate of ventilation and/or the radon (thoron) gas emanation from mine walls are time-dependent. Several cases of practical interest have been investigated including sinusoidal, linear, exponential, stepwise, or a combination of two or more of the above. Analytical solutions were obtained for the time-dependent radon (thoron) gas emanation rate. However, because of the extreme analytical complexity of the solutions corresponding to the time-dependent ventilation rate case, numerical solutions were found using a special Runge-Kutta procedure and the Hamming's modified predictor-corrector method for the solution of linear initial-value problems. The mine model makes provisions for losses of radioactivity, other than by ventilation and radioactive decay, by, say, plate-out on mine walls, and by other mechanisms. Radioactivity data, i.e., radon, thoron, and their progeny. obtained with the above mine model for a number of ventilation and emanation conditions, are presented. Experimental data obtained in an inactive stope of an underground uranium mine for a time-dependent air flow case are shown. Air flow conditions (ventilation rate) were determined by tracer gas techniques using SF6.

Jan 1, 1987

By Manlapig EV, Lawson F, Clarkson CJ

A low grade middling sample from Mount Isa, Australia, assaying 31.7 per cent zinc, 12.9 per cent lead and 14.5 per cent iron was leached under atmospheric pressure in sulphate and sulphate-chloride solutions with ferric ions as oxidants. About 96 per cent of the contained zinc was dissolved into a 0.5 M H2SO4 - 0.5 M Fe2(SO4)3 solution at 90¦C within three hours from a five per cent by weight slurry density mixture. The leaching process is very temperature-dependent, suggesting a surface chemical control. In the latter stage, the leaching rates levelled off and the leaching was most probably controlled by both surface chemical reaction and diffusion processes. The addition of chloride ions in the leach solution resulted in an increase in the leaching rate. About 95 per cent of the lead sulphide contained was converted to lead sulphate which precipitated and remained in the residue. Essentially no lead remained in solution and the low chloride concentration did not affect the precipitation of lead sulphate. Half of the iron orginally present remained in the residue as pyrite although essentially all the cadmium and 90 per cent of the copper initially present were dissolved. Some three per cent of sulphide sulphur was oxidised through to sulphate, about 67 per cent was converted to elemental sulphur which can be recovered by solvent extraction, the rest remained in the residue mainly as pyrite. Ferric sulphate and sulphate-chloride solutions can be used to effectively leach finely ground lead-zinc middlings and other bulk sulphide concentrates. A complete separation of zinc from lead and silver has been demonstrated.

Jan 1, 1993

By M. J. Perpich

Electrochemical and chemical leaching tests were carried out on chalcocite, covellite and chalcopyrite in acidified iron sulfate solutions sparged with a mixture of O2 - SO2. The gas mixture catalyzed the ferrous to ferric oxidation reaction in situ and, therefore, increased the redox potential and oxidizing strength of the solution. Anodic polarization curves in dilute sulfuric acid on copper sulfide electrodes showed that chalcopyrite passivates and dissolves at current densities orders of magnitude less than chalcocite and covellite. The addition of a depassivating agent (Ag+) increased the passive current density of chalcopyrite and caused breakdown near 0.625 V (SCE). The depassivating effect was also observed during the leaching of chalcopyrite particulate samples as small amounts of Ag+ added to acidified iron sulfate solutions in the presence of O2 - SO2 mixtures greatly increased the leaching rate and the total amount of Cu oxidized (> 90%). Passivation was prevented in the absence of Ag+ by decreasing the initial oxidizing power of the solution and by pretreating the sample in a reductive leach. Both of these methods resulted in transformation of the chalcopyrite surface from its characteristic greenish-gold into deep black. Increased concentrations of Fe+++ due to 02 - S02 sparging were then able to oxidize the transformation product.

Jan 1, 1999

By David Norval

Ni, Co, Cu and Pt, mattes are common materials that require granulating and milling of the resultant granules for further processing. This route is acceptable if the material is brittle (friable) which is a property associated with the higher sulphur mattes. For lower sulphur levels, where the matte is less amenable to milling, the costs of the milling increases. This paper will compare water granulation with certain dry granulation processes and the downstream processes required for Hydrometallurgy. It will further introduce and expand on atomisation which offers a further safety benefit in the control of the metal flow into the 'wet zone' with the use of a tundish flow control also reducing the conversion from the matte to powder in one fairly straightforward operation.

Jan 1, 2006

By D. S. Bloswick

An investigation an4 analysis of slip/fall accidents specifically pertaining to underground coal mines was conducted. From a population of 751 accident reports, three major sources of injury which account for over 80% of the incidents have been identified. The specifics of this study are presented in this paper. Based on the results, several recommendations are made to reduce such accidents in underground mines. In addition, a brief discussion of the slip-hazard analysis laboratory at the University of Utah, which will be useful in future analyses of these accidents is presented. Work in this facility includes the simulation of certain mining activities in a controlled setting. Foot forces are measured and work methods subsequently developed to minimize the slip potential of these activities.

Jan 1, 1988

By Tetsuya Uda, Sakae Shirayama

"With the aim of producing nickel (Ni) metal directly from acidic aqueous solution containing cobalt (Co) and other impurities, selective reduction of Ni was examined. As a preliminary experiment, sodium hypophosphite monohydrate (NaH2PO2·H2O) was selected as a reductant, and reacted with aqueous solution containing 0.1 mol L-1 nickel sulfate (NiSO4·6H2O) and 0 ~ 0.05 mol L-1 cobalt sulfate (CoSO4·7H2O) for 3 hours at 90 °C. As a result, it was revealed that Ni was selectively reduced and separated from Co in the acidic region (pH= 4.8). In this study, differences of reduction behavior between Ni and Co were investigated, and the feasibility of Ni I Co separation by the selective reduction of Ni was discussed.IntroductionEfficient Ni condensation and separation from Co are essential in nickel hydrometallurgical processes. Currently, the hydrometallurgical production of Ni from oxide ore is mainly carried out by acid leaching at elevated temperature, followed by the removal of impurities using neutralization, and condensation of Ni and Co into intermediate products such as hydroxides and sulfides. Then, the intermediate product is dissolved in acid aqueous solutions, and Ni I Co separation is conducted by solvent extraction. Finally, Ni and Co are recovered by electro-winning. This complicated process consumes large amounts of alkali, hydrogen sulfide (H2S), and organic solution in a multiple-staged process'. To reduce the consumption of these chemicals, it is important to recover Ni more efficiently from acidic aqueous solution containing impurities."

Jan 1, 2014

By William H. Spice

Drilling activities in South Central Texas for the year 1945 continued the steady increase over the past two years, while new fields discovered for the year included four new gas fields and one field extension. In the 30 counties included in this area, which comprises district No. 1, Oil and Gas Division, Railroad Commission of Texas, 141 exploratory wells were completed, compared with 61 drilled in 1944 and 29 drilled in 1943. Of these 141 tests, 55 were field well and 86 were wildcats; 38 were completed as oil wells, S as gas and gas-distillate producers, and 95 were abandoned as dry. Atascosa and McMullen Counties were the most active in the district, accounting for 73 of the wells drilled.

Jan 1, 1946

By Andre Balt, Pierre Hofmeyr

It is only recently that automation has been applied to mining analytical laboratories. This paper describes the use of automation in the laboratory analytical process of hard-rock mining and geological samples and slurries in mining concentrator plant process control laboratories. Types of analysis include fire assay, XRF, ICP and wet chemistry. The benefits of automation are reduced unit cost of analyses, greatly reduced staff requirements, higher quality of data and very fast turn-around times.

Jan 1, 2005

By K. R. Vost

"In situ" measurements of the surface heat transfer coefficient in underground airways by K. R. VeST,* B.Se. (Glas.), M.Se. (N.S.W.) (Visitor) Few "in situ" measurements have been made of the surface heat transfer coefficient in mine airways despite the importance of this coefficient in determining the heat flow into the ventilating air. In this paper, the values obtained at various air velocities and the comparisons of these values with theoretical values are given. Examples are also given ofthe errors which would result if rock surface temperatures were obtained by extrapolation from temperatures further into the rock without taking into account the time delay which occurs before a given change in air temperature reaches the points from which extrapolation is carried out.

By Jock McGregor, Deepak Malhotra, Leonard Harris

After more than 100 years, alkaline cyanide leaching of gold and silver ores, either directly in the case of oxidized ores, or after pretreatment of refractory ores by roasting, pres­sure leaching or bacterial leaching, remains the dominant r leaching method to extract the precious metals f om ores. Leaching with halides (chlorine, bromine and iodine) and with thiourea and thiosulfates is less common but prac­ticed in some cases to dissolve the precious metals both from ores and jewelry and electronic scrap. Cyanide solutions can contain from 1 ppm Au to 30,000 ppm Au. According to the source, i.e., agitated tank leach­ing, heap leaching, eluates from stripping activated carbon or waste electroplating solutions. Similar variations occur with silver which can have a profound influence on the recovery method. The presence of other elements in the leach solu­tions, particularly mercury and copper, likewise play an important role in the procedures required to recover the gold r and silver values f om solution. The same circumstances are found when lixivants other than cyanide are used to dissolve the precious metals. For decades, the preferred method of recovering gold and silver values from alkaline cyanide leach solutions was by zinc dust precipitation according to the Merrill Crowe process developed in the late 19th century. Finely ground gold and silver ores or concentrates were either leached directly or after roasting, in agitated tanks or Pachucas and subjected to solid/liquid separation by filtering or by treat­ment in counter-current-decantation washing thickeners (CCD). This solid/liquid separation step was often very dif­ficult especially when ores containing high quantities of clay were treated which caused filtration or thickening problems. Following testing and development by the U.S. Bureau of Mines (USBM) in the late 60s, the introduction of carbon­in-leach (CIL) or carbon-in-pulp (CIP) plants to recover gold and silver from leach pulps was one of the greatest opera­tional and cost saving improvements made in the industry in South Dakota and quickly spread around the world to be the most common process to recover gold and silver from cyanide solutions.

Jan 1, 2000

By Edgar L. Collis

NO industry or group of industries is more deeply interested in the influence exerted by atmospheric dust than that concerned with the getting of coal and of metalliferous ores. The coal miner in the past has mainly been interested on account of the part played by coal dust in the occurrence of explosions; but investigation is revealing that coal miners experience, at least on certain coal fields, unduly high mortality ascribed to lung diseases, some part of which may reasonably be attributed to dust inhalation, and that a small group of men employed in sinking shafts and driving roads through sandstone rocks experience troubles identical with those that afflict many metalliferous miners. Coal Mining The Registrar General for England and Wales issues information every 10 years concerning the mortality experienced in various industries. The records dealing with coal mining are of particular interest, since they are given separately for each of the largest fields. When examined they exhibit the coal miner with a favorable death rate on the whole when compared with all other occupied males; but they reveal great differences on the different fields; thus the Lancashire miner in 1900-2 had a comparative mortality from all causes of 1006 as against a figure of 675 for the Nottinghamshire and Derbyshire miners, and in 1910-12 of 941 as against 570 for Nottinghamshire. When mortalities due to four only of the great causes of death are subtracted from the total the differences are greatly reduced; these four causes are phthisis, pneumonia, bronchitis and accidents. Thus for 1910-12 more than one-half of the mortality in Lancashire, 478 out of 941, is so accounted for, but less than one-third of the mortality in Nottinghamshire, 184 out of 570; the latter fraction compares with that for all males, 293 out of 790. Exactly why the accident mortality varies thus with those for the lung diseases has not been determined; the fact, however, points to an interesting association between health and so-called "accidental" occurrences.

Jan 1, 1927

By Michael D. Fenton

Bauxite resources were primarily in Africa, Asia, Oceania, and South America. Only five countries combined, Australia, Brazil, Guinea, India, and Jamaica, contained most of the total world reserves available for extraction under current economic conditions and accounted for nearly 80 % of world production of bauxite. World bauxite and alumina production declined and prices for smelter-grade alumina remained below the $200/mt level during 1993 because of growing aluminum inventories on international markets and declining worldwide demand. The United States imported bauxite primarily from Australia, Brazil, Guinea, and Jamaica. U.S. alumina plant capacity remained essentially unchanged throughout 1993, but apparent capacity utilization decreased by the close of 1993. Chromium Most of the world's known resources and reserves of chromite are located in India, Kazakhstan, South Africa, and Zimbabwe. India, Kazakhstan, and South Africa accounted for 73 % of world production of chromite. The two largest producers of chromite, Kazakhstan and South Africa, were in the process of major economic and political change during 1993. South Africa's production and exports of chromite continued to fall during 1993, because of weak international demand and a flood of cheap metal from the former U.S.S.R. and China into world markets. Despite a significant increase in production, South Africa's ferrochrome producers continued to operate below capacity in 1993. Prior o the dissolution of the U.S.S.R., Kazakhstan was a major internal supplier of chromite ore to the U.S.S.R. consumer, but subsequent decline in demand led to a downward trend of chromite production in Kazakhstan and increasing exports to Europe during 1992 and 1993. The United States consumed, about 10% of world chromite ore production in various forms of imported materials. The United States imported nearly one-half of its required chromium contained in chromite ore and chromium ferroalloys and metal from South Africa; the remainder was from the minor producers Turkey, Yugoslavia, Zimbabwe, and others.

Jan 1, 1995

By A. Baldwin

Reports technical progress in designing four machines to be used in mining coal underground, applying innovative concepts at the design stage (instead of add-ons). A study phase was followed by design activity, including calculations supporting the designs. Scale models of three machines were built, and a full-scale mock-up of the conventional loader was used to measure human factors parameters.

Jan 1, 1976

By Da-Rong Chou

An optimum method for selecting exploratory drilling locations has been developed. The process has been modelled as a highly non-linear programming problem subject to constraints. Solution involves an iterative algorithm which converges rapidly and procedures have been developed to distinguish between local and global optima. The algorithm has been implemented as an interactive computer program which allows the user to influence directly the solution process and to evaluate the effect of any manual adjustments to the optimal solution.

Jan 1, 1984

By W. N. Hamilton

Industrial minerals are plentiful in Alberta. Although exi ting in variety and in quantity, they constitute a minor segment of the province's mineral industry, which is based on oil and gas. In 1983 Alberta led all the other provinces in value of mineral production with a total of $22,2 18 million, 62 per cent of the total for Canada. Of Alberta's total, $22 million or about 3 per cent came from the indu trial minerals. Nearly two-third of this production is accounted for by sulphur, which is actually a by-product of the oil and ga industry. Alberta ranked third among the province in industrial minerals production for 1983, with about 20 per cent of the national total.

Jan 1, 1984

By S. S. Venkata

This volume describes a comprehensive program of research into the reliability of mine electrical power system components and the resultant reliability of the total system. The research effort encompassed analytical models, laboratory testing and field testing. The analytical work included definition of terms, fail rate functions and distributions, failure rate estimation and techniques and procedures for theoretical reliability assessment. One of the primary mine power system components addressed in the study was the ac molded case circuit breaker. This device is known to have low reliability and hence an unfavorable impact on mine safety and productivity. Ac molded case circuit breaker reliability was studied by analytical means, laboratory testing and field monitoring. A similar three-pronged' effort was made to study the reliability of undervoltage relays/releases. Particular emphasis was placed on new solid state undervoltage relays. The reliability of bulk power components, such as trailing cab les, motors, control gear, and other equipment, was assessed by gathering maintenance records from active mines. These data were compared to similar records from other industries. The work was extended to include the reliability, availability, maintainability and safety of these components.

Jan 1, 1979