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By António Fiúza, Anthony Danko, Patrícia Leitão, Aurora Futuro, Cristina Vila, Lurdes Dinis

The average global recovery rates for processing scheelite ores by physical methods are normally in the range 50 to 70%, and it is problematic to attain a minimum grade of 60% WO3 in the concentrates without penalizing further this yield. Direct hydrometallurgical processing of low-grade concentrates or medium- to high-grade ores may become an interesting global economic alternative as it allows increasing the recovery rate, avoiding major penalizations due to the grade of the concentrate and increasing the added value of the final product. Leaching of scheelite by sodium carbonate presents several advantages such as its selectivity regarding the dissolution of troubling metals like iron and aluminium, allowing for a simple and flexible process diagram. However, it has the disadvantage that it is performed at high temperature and pressure with a high consumption of reagents. The feasibility of leaching is appraised by the extraction yield and selectivity, but also by the operating cost. Considering these aspects, a relevant objective of the research was to transform alkaline pressure leaching into a feasible processing alternative directly applicable to both medium- and high-grade ores and simultaneously to low- and high-grade concentrates produced by physical methods. The research used ore samples and low-grade concentrates from a typical skarn orebody as well as high-grade concentrates from a chalcopyrite-scheelite orebody. Different operating conditions were tested. Temperature, pressure and reagent concentration showed to be fundamental, but not exclusive, in determining the leaching behaviour. The operating conditions are milder than the ones generally proposed in the literature or currently in use in industry, but with higher carbonate consumptions. The research was oriented towards potential industrial implementation allowing for the application of optimization methods and straight scale-up to pilot-plan design and project.

By Charles D. Litton

This Bureau of Mines paper describes a novel fire detector that can be used to discriminate between smoke produced by a fire and smoke produced by a diesel engine. The detector uses a pyrolysis technique whereby a sample of smoke- laden gas passes through a short, heated tube within which fire smoke particles pyrolyze and increase their number concentration and decrease their average size, while diesel smoke particles are unaffected. The detector is designed for use in mines that use diesel-powered equipment where the detection of fires is complicated because of the diesel emissions background levels of smoke and other products of combustion.

Jan 1, 1989

By Christopher J. Bise

PRINCIPLES OF MINE PLANNING During the initial planning stages, all mining operations are analyzed and evaluated in a similar fashion. This similarity holds true because the mine-planning procedure can be reduced to a network of interrelated systems that are tied together by a common philosophy of mine planning: namely, that the resource is to be extracted in a manner which is safe, efficient, and profitable. The success of the mining operation cannot be guaranteed unless each of these three requirements is met. Fig. 1 shows a flowchart for the initial planning of any mining operation. Notice that there is a preplanning stage that leads to the planning of four interrelated systems. The preplanning stage includes property exploration, estimation of production and manpower requirements, and the establishment of construction timetables. The four systems, evaluated after the pre-planning stage, are broken down into the following: (1) Excavation and handling system, (2) Strata control system, (3) Operating support system, and (4) Service support system. The Excavation and handling system includes the selection of all the equipment for the removal of the resource from its in-place deposit (e.g., draglines, continuous miners, rock drills, etc.) and for the transportation of the mined material from the face (e.g., belt conveyors, trucks, etc.). The Strata control system incorporates all those considerations which maintain the integrity of the roof, ribs, floor, and overburden both during and after the extraction phase; typical considerations in this area include pillar sizing, artificial support of the immediate roof in mine entries, and subsidence protection. The Operating support system contains the "necessary evils" of mine planning; the system consumes a large percentage of the mining engineer's planning time but does not contribute to the actual extraction of the resource. However, if proper attention is not paid to the various components of the system, such as ventilation, drainage, and power, then the mining operation will not perform to its capabilities. Finally, the Service support system is composed of those operations which keep the mine running efficiently; typical examples of these include maintenance and sup- ply. One important concept that Fig. 1 is designed to emphasize is that the four systems are interrelated; typically, a slight alteration of one can affect the performance of another. If these interrelationships are ignored, the effects on the system can be disastrous. The mine preplanning stage and the four subsequent system evaluations constitute the Analysis portion of the mine planning flowchart. After this portion of the study is completed, the overall projected operation can be evaluated by techniques such as financial analysis. This last step in the study is referred to as the Synthesis of the previously calculated parameters into an overall plan. Much has been written about the overall evaluation of mining properties, but, over the past thirty years, very little has been written about the analysis of mine- planning systems in a coordinated manner. Further, those texts which attempted this topic have failed to give sufficient examples for successful implementation, thus supporting the operating engineers' lament that it is easy to discuss theories but difficult to show applications. This text is intended to bridge this gap. Examples of the various stages of the analysis portion of the mine planning flowchart shown in Fig. 1 will be covered in this text, with the exception of the Service support system, since this system is oriented more toward day-to-day planning than long-term mine planning. INTERNATIONAL STANDARDIZATION The benefits that can be derived from an international standardization of the units used in mining engineering calculations are numerous. The interchange- ability of equipment parts and the ability to analyze and compare performance and design specifications on an equal basis are just two of the goals desired by both manufacturers and mine operators. Unfortunately, conversion to an international standard has not been rapidly achieved by engineers in the United States, due to their training under the English system. The Society of Mining Engineers of AIME has made the commitment for the adoption of the Systeme International d'Unites (SI) in all mining engineering calculations. Since many practicing mining engineers and students in undergraduate programs still find difficulty in relating to SI units, the calculations in this textbook will use the English system, with Table 1 available for conversion into SI units.

Jan 1, 1986

This geometallurgical study examines the gangue mineral variability at the Bingham Canyon porphyry copper mine in Utah. Understanding an orebody?s mineralogy is important for mine and mill planning because it provides information on the size, texture, and distribution of ore minerals, the relationship between ore and gangue minerals, and the extent and type of alteration. Quantification of the mineralogical variability and properties of an orebody provides valuable input to the ore model and may have a significant effect on recovery optimization. This study was designed to be carried out on an initially detailed scale in order to develop a robust methodology for measuring and quantifying specific parameters, such as the distribution of mineral phases, alteration assemblages and fractures from key ore domains at the Bingham Canyon mine (Figure 1). Details of the methodology are reported below. This technique can be applied to testing the impact of mineralogy on a number of processing parameters. [ ] Figure 1. Ore domain map of Bingham Canyon (Kennecott Utah Copper, 2003) showing the 33 geometallurgical ore domains. The samples for this study were collected from the northwest part of the deposit circled on the map. PROJECT BACKGROUND Geology The Bingham Canyon deposit is a large porphyry Cu-Mo-Au deposit with associated skarn and base-metal replacement deposits mined in an open-pit mine measuring about 2.5 miles across and 4,000 feet deep. The deposit is hosted by the Bingham Stock, a Late Eocene to Mid-Oligocene intrusive complex. The skarn is hosted by the Late Carboniferous-age Bingham Mine Formation, which is comprised of quartzites and basal limestones (Babcock Jr. et al., 1998). The Bingham Stock is a composite intrusive complex that was emplaced over a period of about two million years. The oldest phase is described as a fine-grained equigranular monzonite (MZ), which intruded the country rocks at 39.8 ± 0.4 Ma (U-Pb zircon TIMS age) (Parry et al., 2001). Subsequently, the quartz monzonite porphyry (QMP) was emplaced, followed by intrusion of a latite porphyry (LP). The final intrusive phase, which forms narrow dikes that crosscut the Bingham Stock, is represented by a quartz latite porphyry (QLP), which is dated to 37.5 ± 0.4 Ma by 40Ar/39Ar dating of sanidine (Deino and Keith, 1998). Also present, are a minette dike in contact with a QLP dike (Waite et al., 1998; Deino and Keith, 1998), and a biotite porphyry (BP), a quartz latite porphyry breccia (QLPbx), and a pebble dike (Redmond, 2002). The copper orebody is centered above the Bingham Stock and forms an inverted cup shape with three high-grade copper zones extending to depth. Molybdenite mineralization occurs within and extends below the copper orebody, but is not correlated with copper mineralization. The main sulfide assemblage is chalcopyrite, bornite, molybdenite, and pyrite. Gold is locally intergrown with chalcopyrite and bornite (Babcock Jr. et al., 1998; Phillips et al., 1998). The surrounding country rocks host skarn deposits with three main ore types - garnet skarns, massive sulfides, and iron oxides. The garnet skarns contain chalcopyrite and pyrite with magnetite veins. In the massive sulfides chalcopyrite and pyrite occur either in banded sulfides or in unconsolidated microbreccias. The iron oxides contain disseminated chalcopyrite with minor chalcocite and bornite (Harrison and Reid, 1998). The deposit is overprinted by several stages of alteration. Potassic alteration is concentrated at the center of the deposit. It is surrounded and partially overlapped by a propylitic alteration zone. Both zones are overprinted by sericitic alteration. In the northern part of the deposit evidence for argillic alteration can be found (Bowman et al., 1987). Similarly, the skarn deposit was also overprinted by several stages of alteration: wollastonite, idocrase, and garnet in cherty limestones, and quartz and diopside forming in calcareous quartzites. Distally, diopside was replaced by talc, tremolite, dolomite, secondary calcite, and pyrite, and quartz and sulfide veinlets with biotite and actinolite selvages are present. Andradite garnet, diopside, quartz, magnetite, hematite, and copper sulfides were overprinted by wollastonite (Babcock Jr. et al., 1998). Because the monzonite, quartz monzonite porphyry, latite porphyry, and quartz latite porphyry host the bulk of the mineralization, our research is focused on these lithologic units. Geometallurgy On the basis of geological (lithology, alteration assemblages, fracture density, copper mineralization) and metallurgical properties, the deposit has been divided into 33 ore domains by mine geologists and metallurgists (Figure 1). In map view, these domains cross geologically defined boundaries (MZ, QMP etc.). These domains reflect regions of the deposit that have particular, mapable attributes or properties. They reflect a combination of geological and mineralogical characteristics that combine to impact processing. Alteration, for example, as shown by talc mineralization, is one such key feature. Hardness may reflect the absence of sericitic but presence of potassic alteration. Structural discontinuities such as faulting, fracturing, or development of void

Jan 1, 2009

By J. E. Murphy

The Bureau of Mines demonstrated ferric chloride leaching of galena concentrate on a continuous bench-scale basis. Leaching was performed at 95° C and with a contact time of 15 min. The ferric chloride leaching solution was continuously fed to a leaching tank at a constant rate for periods up to 45 h. In each test a constant redox potential was maintained in the slurry exiting the leaching tank by controlling the concentrate feed rate. In the 45-h test, lead extraction exceeded 99.5 pct, and the lead chloride produced was 99.97 pct pure.

Jan 1, 1984

By Greg Partington, Darryl Thorburn, Charlene Wildman, Elisa Puccioni, Connie Payne, Campbell McKenzie

"Mineral prospectivity modelling of polymetallic nodule deposits has been completed over the Cook Islands Exclusive Economic Zone (CIEEZ) using the GIS based Weights of Evidence modelling technique. Polymetallic nodules, also known as manganese nodules, have been explored as a possible resource for a number of metals including cobalt since the early 1970s. Recent data on the nodule composition and abundance in the CIEEZ has led to a renewed interest in the prospectivity for manganese nodules in the region. The predictive modelling has used the most recently accepted mineral model for polymetallic deep-sea nodule deposition to identify factors that are most likely to map the presence of this type of mineralisation in the CIEEZ.Manganese nodules form on the deep seafloor as concretions formed by concentric layering of iron and manganese hydroxides around a core and they grow at a very slow rate, on the order of millimeters per million years. The available data for the CIEEZ indicates a greater abundance in the area of nodules formed by hydrogenetic processes, which are the result of slow precipitation of metallic components from seawater. The environment in which the nodules are most abundant is at depths between 4,000 m and 6,000 m in areas of low sedimentation rate. Hydrogenous nodules commonly grow on siliceous and pelagic clay sediment, they are less common on other types of sediment."

Sep 1, 2014

By R. S. Kinasevich

As part of other work related to the studies of kinetic factors that influence the flotation of specific sulphide minerals, specially designed kinetic flotation experiments at Cominco included work done on -65 + 100 mesh and -100 + 150 mesh, high purity galena. The flotation collector used was sodium isopropyl xanthate containing radioactive sulphur-35. Radiation monitoring of the galena fractions from stage flotation tests indicated that the adsorbed radioactive xanthate was uniformly distributed among the floated fractions and the non-floated, or residual portion of the galena. This anomalous behaviour could not be correlated to changes in Seebeck coefficients, to lattice distortions, or to the nature of the mineral surface as revealed by infrared spectroscopy and by microscopic measurements.

Jan 1, 1970

By Geoffrey Hughes

The Narragansett Bay Commission (NBC) is a regional sewer authority that serves ten communities in the Providence, Rhode Island metropolitan area. From 1992 to 1999, the NBC developed a comprehensive facilities plan to abate Combined Sewer Overflow (CSO) pollution in the Upper Narragansett Bay. The plan underwent many major evolutions during this period, most notably the addition of a stakeholder?s process by which NBC demonstrated a site-specific plan to control the pollutants and meet water quality standards. The favored solution consisted of deep tunnel storage with treatment at existing wastewater facilities that had been recently upgraded. In 1999, a final plan was accepted which included two tunnels, five CSO interceptors, twelve sewer separation projects, a wetland facility, and a wastewater treatment facility upgrade. The program is to be constructed over 20 years in three sequential phases (Figure 1). Phase I of the program includes a 4,963 m (16,284 ft) long, 7.9 m (26 ft) diameter, 70.1 m (230 ft) deep storage tunnel; seven drop shafts with connecting adits; ancillary facilities; and a pump station. Construction of Phase I began in 2001 and is expected to be operational by October 2008. This paper focuses on design and construction of the Fields Point Tunnel Pump Station (FPTPS)located at the south end of the main spine tunnel. A189 Ml/day (50 MGD) pump station is required to lift CSO flows from the tunnel to the Fields Point Wastewater Treatment Facility (FPWWTF). The pumps are to be housed in a 35.6 m × 18.6 m ×20.7 m (117 ft × 61 ft × 68 ft), 91.4 m (300 ft) deep cavern excavated in a complex meta-sedimentary rock of the Rhode Island Formation, and connected to the surface by 9.7 m (32 ft) and 3.4 m (11 ft) diameter shafts. Factors which influenced selection of the size, configuration and location of facilities included the preferred arrangement of pumps, critical aspects of site geology, and estimated cost. Technical and value engineering reviews also affected the final design. Following Notice to Proceed (NTP), concerns were raised by the contractor regarding constructability and design. Additional geotechnical investigation and independent engineering review were employed to validate the design assumptions. The cavern was successfully excavated and sup-ported in rock, completed on schedule and within budget in 2005. In 1992 the NBC retained Louis Berger Group (LBG) as Program Manager (PM) for the CSO Abatement Program. LBG thereafter formed a design team including: Jacobs Engineering Group(JEG) as the designer for underground structures and near surface collection facilities; Black and Veatch(B&V) to design the pumping system and associated facilities; Haley and Aldrich (H&A) to oversee the geotechnical program; and Malcolm Pirnie to design the system-wide instrumentation and control system. Construction management, resident engineering, and inspection services were provided by the joint venture Gilbane/Jacobs Associates (G/J).

Jan 1, 2008

By Florian Häckel, Ulrich Schwarz-Schampera, Benjamin Bühring, Katja Schmidt, Dieter Garbe-Schönberg, KoschinskyM Andrea

"The Vanuatu island arc and its adjacent back-arc basins form part of the southern New Hebrides subduction system in the southwestern Pacific Ocean within a triangle defined by the Solomon Islands, New Caledonia and Fiji (Meffre & Crawford 2001). The back-arc region east of the volcanic front is characterized by three structural depressions namely Vate, Erromango, and Futuna (from N to S), also known as the Coriolis Troughs. Earlier studies of lava compositions reveal the occurrence of highly evolved alkali-rich dacites as well as ankaramite basalts within the individual troughs (McConachy et al. 2005).Here we present the first mineralogical and geochemical analyses of hydrothermal fluids and precipitates (sulfides, sulfates, Fe-oxyhydroxides), sediments, and volcanic rocks, sampled during the "Coriolis Volcanism and Vents" (COVOLVE) cruise SO229 in July 2013 aboard the German R/V Sonne. The samples were retrieved during several ROV Kiel 6000 dives directly from the newly discovered active vent sites at the neovolcanic Nifonea Ridge, and from multiple sites at water depths ranging between 200 to 2800 m within the Vate and Futuna Troughs as well as from the shallow water Epi Caldera NNE of the Coriolis Troughs (Fig. 1)."

Sep 1, 2014

The Northside Storage Tunnel Project in Sydney includes over 20 km of TBM driven tunnels, over three km of declines and major caverns and pump rooms. The paper describes methods used for design on the project. Emphasis is given to the refinement of the use of empirical rock mass classifications, and to the use of discontinuum numerical methods. The use of empirical rock mass classifications in Sydney sandstone has usually led to conservative design because the systems are based on a random orientation of joints in the rockmass. Because the joint sets are usually oriented in a way that is beneficial for tunnelling, limits must be placed on the parameters used in the classifications system. The paper discusses these limits and the derivation of the parameters. The use of numerical methods in Sydney sandstone is discussed. Continuum methods have their uses, but discontinuum methods are preferred. The use of UDEC has been validated against a previous project, the New Southern Railway. Recommendations are given for UDEC models. In Sydney's geology, so advantageous for tunnelling, the challenges of this project have been to make the best use of the good conditions, while maintaining safety for the workforce and the future operators of the project.

Jan 1, 1999

By S. Al-Thyabat

Conditioning of flotation feed is an important prerequisite for efficient flotation. This process depends on parameters such as conditioning time, slurry concentration and slurry pH. The objective of this paper is to optimize the conditioning process for the flotation feed. This was achieved by first conducting preliminary experiments at constant slurry pH to determine the significant ranges of slurry concentration and conditioning time. Then, factorial experimental design (32 experiments) was used to investigate the significance of the above parameters and their interactions on flotation recovery and grade. Statistical analyses using ANOVA approach showed that flotation recovery (R) and concentrate grade (g) were affected by feed conditioning. It was found that concentrate grade was linearly proportional to the slurry concentration and conditioning time, while flotation recovery was exponentially proportional to the conditioning parameters. A contour plot of the flotation response (recovery and grade) against conditioning parameters showed that the optimum operating parameters for flotation feed conditioning was a conditioning time of 1.5 to 2 minutes and a slurry conentration of 55% to 60%.

Jan 1, 2008

By Huijun Shao, Qiang Liu, Zhengming Yi

The increase of the proportion of high Al2O3 content iron ore fine in iron and steel enterprises has brought about a series of problems such as the increase of the viscosity of blast furnace slag and the difficulty of the separation of slag and iron. In order to solve this problem, the effect of increasing MgO content on the technical and economic index, the cold strength, and metallurgical properties of high basicity and high-alumina sinter was studied through sinter pot test. Nova400NanoSEM field emission scanning electron microscope was used to analyze sinter microstructure. The experimental results show that when the MgO content fraction in the sinter with high basicity and high aluminum increases from 1.72 to 2.49%, the vertical sintering speed decreases by 4.38mm/min, the utilization coefficient decreases by 0.51t/(m2 h), and the low-temperature reduction degradation index increases by 6.7%. When MgO content in sinter is 2.11%, drum index and reducibility index are the highest, reaching 61.93% and 86.39% respectively. Mg2+ is mainly solid dissolved in the magnetite lattice and replaces Fe2+, up to 3.64%. The generated magnesie-containing magnetite inhibits the phase transition from Fe3O4 to Fe2O3 oxidation process in the sinter cooling process, which reduces the generation of secondary hematite and is conducive to improving the low-temperature reduction degradation performance of sinter.

Jul 4, 2021

By Susana Bolhão Muiños, José Hipólito Monteiro, Martin Frank, James R. Hein, Henrique Garcia Pereira, Fátima Abrantes, Tracey Conrad, Luís Gaspar

In spite of all the work that has already been done on ferromanganese deposits, studies on the Atlantic Ocean occurrences are still in their infancy and there is a clear need for investigations concerning the origin, distribution, and resource potential assessment of these deposits. Nevertheless, studies already carried out on northeast Atlantic seamounts indicate the general presence of ferromanganese deposits of hydrogenetic origin, i.e. deposits formed by direct precipitation of colloidal, hydrated metal oxides that are scavenged from the water column on hard-rock substrates. The hydrogenetic precipitation promotes the enrichment of ferromanganese crusts in many trace metals, most of which are of economic interest, such as Co, Ni, Te, rare earth elements, and platinum-group elements and thus ferromanganese crusts are considered an important metal resource.

Sep 1, 2014

By Ehsan Moosavi, Kamyar Tolouei

In open-pit mines, the long-term production scheduling optimization problem (LTPSOP) is a complicated problem that contains constraints, large datasets and uncertainties. Due to its dimensions and NP-hard nature, it is usually difficult to find an ideal solution to the LTPSOP. The optimal schedule generally restricts the ore, metal and waste tonnages, average grades, and cash flows of each period. In this paper, to synthesize grade uncertainty into the strategic schedule, a stochastic integer programming (SIP) framework is presented to LTPSOP. The objective function of the SIP model is to maximize the net present value and minimize the risk of deviation from the production targets considering grade uncertainty simultaneously while satisfying all technical constraints and operational requirements. Instead of applying one estimated orebody model as input to optimize the production schedule, a set of equally probable orebody realizations is applied to synthesize grade uncertainty in the strategic schedule and produce a more profitable and riskbased production schedule. To solve the LTPSOP, the hybrid approach with the augmented Lagrangian relaxation method, the Harris Hawks optimization, the Random Forest method and Monte Carlo method was proposed. To indicate the applicability of the model, a case study on a gold mine was implemented. The framework displays the capability to minimize risk and improvement in the expected net present value and financial profitability .

Jun 25, 2023

By J. Bigu

Ventilation conditions in working environments are usually studied by anemometry or, in complex cases, b using special tracer gases such as SF6 and 85Kr. in conjunction with chromatographic and radioactivity techniques, respectively. In some working environments, such as underground uranium mines, however, use can be made of the natural radioactivity environment (e.g.. 222rn. 220rn, and their progeny) to investigate mine ventilation conditions of practical interest. Theoretical studies and experimental data in several underground uranium mines and mine locations show that certain thoron progeny to radon progeny concentration ratios are very good indicators of ventilation conditions. Furthermore, the growth and decay of radon progeny and thoron progeny provide valuable information on mine air residence and clearance times. Some specific examples have been analyzed, such as bacterially-assisted uranium leaching operations in a partially enclosed stope, and the effect on the underground environment of turning ventilation fans on and off for a period of time. Air residence times and other variables of interest, determined from the mine radioactivity environment, were compared with more traditional techniques, such as anemometry and tracer gas chromatography. These studies were also extended to a wet non-uranium mine which exhibited relatively high concentrations of radon and its progeny.

Jan 1, 1989

By Jordan Scheremeta, Sudhir Tripathi, Mahfooz Alam

Injection leaching can improve leach ore recovery by displacing retained solutions, enhancing ore wetting, and creating new flow paths for efficient solution collection. This paper presents a method to assess the feasibility of injection leaching in finer-grained, potentially contractive ores (from a geotechnical slope stability perspective) using limit-equilibrium (LE) slope stability analysis and static deformation modeling. LE models were carried out by assigning peak undrained strengths to the heap leach ore material, and modeling the excess pore pressure induced during the injection leaching process using spatial function in Slope/W. Static deformation modeling was completed using the software Fast Lagrangian Analysis of Continua (FLAC) to evaluate the potential for deformations due to the excess pore pressures induced during the injection leaching process. A constitutive model was used to represent the geomechanical behavior of the leached ore material, which enables the prediction of deformation and potential stability issues resulting from excess pore-pressure induced during injection leaching process. The two-pronged approach provides a practical method to assess geotechnical impacts and guide data-driven decisions in injection leaching operations.

Feb 22, 2026

By G. T. Adel

The growing interest in column flotation has created a need for a fundamental scale-up procedure which is capable of meeting the necessary design and control criteria for industrial columns. Unfortunately, most of the avail able scale-up procedures deal with column diameter only and not overall column volume. Current work focuses on the effect of bubble size distribution and air hold-up on the scale- up of column volume. A series of pressure transducers has been used to measure air hold-up along the length of a bench-scale column. These measurements have been used to validate a mathematical model of the air phase. In addition to scale-up, the model appears to have the potential for use in control of air hold-up and bubble size.

Jan 1, 1990

By Paul H. Johnson

Chemical mining may be defined as the in-place extraction of metal values from ores located within the confines of a mine (that is, broken or fractured ore, stope fill, caved material, or ores in permeable zones) or ores located in dumps, prepared ore heaps, or tailing ponds. The term solution mining has, in general, been used to mean the in-place dissolution of water-soluble mineral salts with leach solutions. Chemical mining is presently in its embryonic stage. Basic research needs to be done to understand the influence of physical and chemical factors in chemical mining, and applied research needs to be done on both a small and a large scale to develop practical techniques of field practice. The areas of research include the following: (1) Leaching chemistry, the influence of physical, chemical, and biological factors in in-place leaching (2) Hydrodynamics of chemical mining systems (3) The development of new, as well as old, leaching agents for use under chemical mining leach conditions (4) The development of new means of contacting fine and coarse materials (with solutions) under static leach conditions (5) The development of new processes for generating and regenerating chemical mining leach solutions (6) The development of metal recovery processes

Jan 1, 1969

By K. Oraee

Excessive emissions of methane from the coal seams can have a serious adverse effect on both safety and productivity of longwall coal faces. Mechanization of coal faces has increased production possibilities to the extent that normal ventilation systems may not be able to ventilate coal face areas in order to lower methane content in the air to within legal limits. Production increases may therefore be prohibited for this reason, especially in gassy seams. Methane drainage from the coal seam by means of long holes and before production starts can act as a useful remedial action. In this paper a two dimensional mathematical model has been produced. The model that is based on finite elements, simulates a methane drainage system where the resultant risk is linked to the coefficient of diffusion, coal permeability, holes pattern and the duration for which the seam is subject to drainage. It is concluded that methane drainage of this type can assist in achieving production increases in many coals seems, especially where high gas content is a virtue of the seam.

Jan 1, 2010

By H. H. Hughes, J. G. Dunn, P. G. Fernandez, H. G. Linge

Dissolved Arsenic (As) is stabilised primarily as As(III) and As(V) and enters ground water streams from sources such as the increasing metallurgical processing of As - containing ores [1]. As(III) is more toxic than As(V) and is less effectively removed from solution by oxide precipitation. Even for dilute As(III) solutions, skin contact or ingestion can cause dermatitis or cancer and there are stringent effluent control standards in place for As containing effluent from mining operations [2]. Chemtronics (Perth, Australia) has manufactured a compact digital voltamme­ter, based on anodic stripping voltammetry (ASV) and suitable for use in the laboratory or field. In this paper we demonstrate the utility of this equipment for measuring As(III) concentration with a detection limit of ca. 10 ppb.

Jan 1, 1995