Search Documents

By Jonathan Peck, Jim Gray

"While the mine developer looks for bigger and better orebodies in countries offering lower risks to development capital, the opera-tor of existing mines is looking for bigger and better ways to use his existing resources. Mining operations today utilize a variety of stand-alone systems for planning and managing their operations. In both small and large mines, payroll, accounting, inventory, planning, and engineering requirements are met using a combination of manual and computer-based systems.Technical advances and new enabling technologies are changing how mines are doing business. PC-based systems are allowing small operations to join the larger mines in using advanced computer-based systems. Advanced monitors are being used in maintenance to track, predict and correct the health of production equipment. Production monitoring systems are used to measure the performance of operating equipment and personnel in real time. This detailed information on how much, where, when, and by whom is being used for proactive management and planning. Ultimately, this information can be used to optimize and control the machines’ activities, eventually leading to robotic and autonomous operation of mining equipment.As the use of technology increases in mining, specific information objectives are being met but other problems are being created. The life cycle of technology is small, and as current systems are replaced by newer ones, integration problems and additional end-user training are created. In addition, onboard monitoring systems can create large volumes of data, data which are frequently archived without being analyzed. Mine operators are also duplicating efforts applying new technologies in an effort to be more competitive, but in doing so are creating interfaces which are only compatible with their own facilities. As system development moved from the centralized mainframe computer to the PC environment, the fragmentation of these systems became more pronounced.To efficiently continue in adapting and utilizing advancing technology, the mining industry needs to develop a system architecture that readily integrates as many sub-systems as possible. This will provide a framework for existing system integration and design guide-lines for future development. The Total Mining System (TMS) concept will allow a network of stand-alone functional modules to be readily integrated with minimal effort. This paper will discuss some of the current technologies cur-rently in use in some surface mine operations.In addition, a description of the information system and communications requirements that will be needed to integrate these components in the future, will be discussed."

Jan 1, 1996

By A. R. Sorta, D. C. Sego

ABSTRACT Temperature, solute, texture, and thixotropic effects on time domain reflectometry (TDR) measurements of water content in oil sands tailings are investigated. Results indicate that TDR water content measurements are influenced by temperature, residual bitumen, and percent clay in the tailings. A correction of 0.03–0.10/ °C must be applied to the apparent dielectric constant (Ka) to account for the effect of temperature. The Ka-volumetric water content relationships of slurries differ significantly from the commonly used Topp calibration equation. The age of the tailings and the addition of phosphogypsum did not influence TDR water content measurements.

Jan 1, 2013

By V. S. Papezik

Pyrophyllite, an AI silicate used in the production of ceramic materials, is formed mainly by alteration of felsic to intermediate volcanic rocks, either directly (at temperatures of 250-300°C and pressures of 1-2 kbar) or by subsequent low-grade metamorphism of aluminous protoliths produced by thermal fluids or even by prolonged weathering. Most pyrophyllite deposits in North America are concentrated in a belt of Late Precambrian volcanic and sedimentary rocks, the "Avalon Zone ", which extends along the eastern flank of the Appalachian mountain system from Newfoundland to the southeastern U.S.A. The only producing pyrophyllite mine in Canada is an open pit located near the settlement of Foxtrap on the Avalon Peninsula of Newfoundland. It lies in a belt of rhyolitic flows and pyroclastics intruded by a granitoid pluton. The rocks have been leached along a shear- or fracture zone, depleted in silica, alkalies, Ca, Mg and Fe by the action of hydrothermal fluids, and recrystallized to a very fine-grained massive assemblage of pyrophyllite, muscovite ("sericite") and quartz. High-grade pyrophyllite lenses contain small nodules of diaspore with minor barite; rutile is present in trace amounts. The close proximity of all pyrophyllitized zones on the peninsula to the granite contact suggests that the alteration was produced by thermal fluids genetically connected with the granitoid pluton. The fine-grained pyrophyllite-bearing rocks, with their simple mineralogy, are suitable for quantitative modal analysis by X-ray diffraction. Chemically analyzed samples from the alteration zone were used for the construction of working curves by plotting calculated mineral content against the intensity of selected diffraction peaks. The accuracy of the resulting curves is ±4.5% for quartz, ±3.6% for pyrophyllite and ±2.7% for muscovite. Pelletized samples give best results. The XRD method is suitable for a rapid analysis of a large number of grab or core samples to outline higher-grade areas for more detailed sampling.

Jan 1, 1978

By Ramon S. Pizarro

The Masbate Province, Philippines, has been a gold producer for many years. Several gold properties were profitably operating until the outbreak of World War II in 1941. One of these properties was the Masbate Consolidated Mining Company that at the time showed an impressive production rate of more than 4,000 metric tons of ore per day and one of the lowest milling costs on record in the country at that time. Interesting enough, t was the milling equipment left abandoned at Masbate that gave birth to one of the giant copper producers in ASIA. In 1955, Atlas Consolidated Mining and Development Corporation started a new operation at its copper property in Cebu with the seven 2.4m 0 x 3m long (8'0 x 10' long) ball mills left abandoned at the old Masbate Gold Mine. Now, 25 years later, Atlas is processing over 100,000 metric tons of copper ore per day through its three copper concentrators, and, the seven old mills are still grinding, copper ores now.

Jan 1, 1981

By M. O. Makwarela, M. W. Erwee, K. Bisaka

"Energy efficiency in mining and minerals processing forms part of Mintek’s long-term research strategy which includes a specific programme designed at overcoming the challenges faced by the South African pyrometallurgy industry.The electric smelting industry is currently severely constrained by the global economic downturn as well as by the availability and increasing cost of electricity. Efficient utilisation of electricity through energy recovery systems and improved smelting process flowsheets can significantly contribute towards creating sustainable operations.Apart from efficient engineering design and solid process control, smelting of either cold or hot pre-reduced ores has been shown to decrease furnace electricity consumption by more than 40%. Various methods of solid-state reduction tests have been carried out at Mintek in order to select the most appropriate process option in the context of the South African industry. This paper summarises a subset of the results obtained, specifically on pre-reduction tests done on South African chromite and manganese ore pellets.In this set of tests, it was found that the use of an organic binder, together with B2O3 as flux, promotes manganese ore pre-reduction, but retards the pre-reduction of chromite. By pre-reducing the manganese ore feed, significant cost savings can be achieved in subsequent smelting processes and there is potential to minimise manganese losses as a result of fuming, due to possible lower operating temperatures."

Jan 1, 2016

By Mahesh C. Jha

Cyanidation has established itself as the main process for extracting gold from ores in this century. However, many ores exhibit refractoriness to the conventional cyanidation process. The main cause of the refractoriness is generally the presence of carbon, tellurium, and sulfides, particularly those of antimony, arsenic, and iron. The problem is usually solved by either modifying the cyanidation conditions or providing an oxidation pretreatment. This paper presents results from studies that help in understanding the causes of refractoriness of various gold ores. This is followed by a discussion of many processes that have been developed to solve the problem such as intensive cyanidation, pressure cyanidation, carbon-in-leach cyanidation, and pretreatment processes such as roasting, chemical oxidation, autoclave oxidation, and bacterial oxidation.

Jan 1, 1986

By N Haque

Base metal ores contain low levels of toxic/hazardous elements such as arsenic, antimony, bismuth, cadmium, lead and mercury. Given the large tonnage of base metal ores mined and processed each year globally, the accumulated mass of minor elements introduced into the biosphere is large and could be expected to have a significant environmental impact. Life cycle analysis (LCA) is a methodology that has been developed to assess the environmental impacts of material supply chains over their entire life cycle. Assessing the toxicity impacts of metallic wastes and incorporating these impacts into LCA methodology is not a simple task given the complexity of the issue. However, research and methodology development is in progress internationally to address this. Despite limitations concerning the lack of a coherent framework for characterising the toxicity impacts of metals, including issues such as bioavailability, a study was carried out to give first estimates of the relative toxicity impacts of various waste streams from metal production processes. The wastes considered were: red mud; sulfide tailings (copper, nickel, lead/zinc); lead/zinc slags; synthetic rutile residue; iron oxide residue; and copper slags and anode slimes. These toxicity estimates can be considered the æworst caseÆ scenario for these wastes, where all the metals present are bioavailable. Combining estimates of the amounts of the various waste streams produced in Australia each year with the toxicity results showed that despite their relatively low human toxicity impact per unit mass compared to some other waste streams, red mud and the various sulphide tailings had the highest annual human toxicity load on the environment, along with copper smelting slag and dust. Data from the pH dependent leaching test reported in the literature were assumed to represent first approximations of metal bioavailability and used to compare the two approaches to estimating the toxicity impacts of red mud.

Jan 1, 2009

By L. A. Garfield

Since the start of mining operations at White Pine in 1953, over 22 miles of drifts have been driven for the purpose of developing the ore body. The drifts, normally driven in multiples of three or five headings, serve as conveyor belt routes, ventilation ducts, equipment and haulage roads, and initial access to mining blocks. Development openings in the flat-lying, bedded ore body are driven in rectangular section from 16 to 32 feet wide and from 8. 5 to 16 feet high. The floor level normally coincides with the bottom limit of the chalcocite values and the roof or back is carried at the most competent stratum adjacent to the top of the ore. A development front consisting of five headings and associated crosscuts is advanced at an average rate of about 100 feet per month using conventional drill and blast techniques and equipment. The cyclic nature of the functions involved in driving the openings and the need to include them in production schedules preclude significant improvements in advance rates using current drill, blast, muck, and haul sequencing.

Jan 1, 1969

Pillars are used in various forms in underground mining. For several decades pillar design has been an issue in both soft and hard rock underground mining. The major use of pillars is in room-and-pillar type mining. Pillars are critical structures in the production levels of block cave mines. With most mines leaning towards the use of block caving for ore extraction today, pillar design has become even more important. Empirical pillar design is popular. The use of numerical modeling is becoming more common in the design of underground mine pillars. A critical review of both the empirical and numerical modeling approaches to the design of underground mine pillars reveal some fundamental flaws. In general, pillar design approaches often assume the pillars are vertical, and are subjected to pure compression. Pillar failure criteria are then based on this assumption. Most papers on numerical modeling for pillar stability assessment use vertical pillars. This paper shows that where pillars are not subjected to pure compression the empirical pillar design approaches are inadequate, and that when using numerical models for the assessment of pillar performance, more care is needed in the determination of the average pillar stresses. The practice of relating field scale pillar strength to laboratory scale intact rock strength determined from conventional laboratory compression tests in empirical design equations is misleading when pillars are inclined or subjected to compressive and shear stresses. New data is added to the hard rock empirical pillar stability chart, and it is shown that it is misleading to conclude that failure of pillars with width to height ratios greater than 2.3 should not be anticipated. New empirical pillar design charts are presented for pillars at various degrees of inclination for different ko-ratios.

Aug 1, 2013

By Peter Moser, Finn Ouchterlony, José A. Sanchidrián

"Blast fragmentation data in the form of percentile fragment sizes as function of specific charge oftenform a set of straight lines in log(size)-log(energy) space that tend to converge on a common focal point.Single-hole shots in specimens of virgin material clearly show this and the phenomenon is called the fragmentation-energy fan. Field data from bench blasting in rock scatter much more but may be interpreted to form such fans. The slopes values of the fan lines depend primarily on the percentile level. This property can be derived from sieving functions of the form P[ln(x/xmax)/ln(xmax/x50)]. An example is the Swebrec function when the parameter b is constant."

Jan 1, 2017

By Gerald L. Colborne

The major role of financial institutions in the free world in the development of mineral resources is to provide the necessary capital in the form of loans to underwrite the development of these resources by the industry on a stable and continuous basis. This capital provided by the depositors to the bank must be invested in sound projects where the degree of risk is relatively small, the return on the investment is reasonable and the time to retire the loan is of short duration. Money is, therefore, one of the important ingredients along with technology, manpower and an exploitable resource that will provide a sound economic base in this region of development. Canadian banks are similar to banks of other western nations, although each country has some differences in their banking systems. The basic difference between the American and Canadian systems is that the former employs unit banking while the Canadian utilizes the more mobile branch system, which is prohibited or restricted in the United States and some other countries. Canadian banks are the subject of this paper, so, subsequent material will relate to Canadian banks unless indicated otherwise. It will be realized by everyone that the mineral industry is only one area of the economy in which the banks are interested and to cover the subject matter in the time allowed, the topic is restricted to mineral resource development. In Canada this is a vital sector of our economy and before we outline some of the details of financing and services involved in various aspects of mineral development, a review of the Canadian mineral industry is a necessary part of the sequence of presentation. The writer presents this material as a resource engineer advising a major bank in mineral matters, so the presentation may relate more to the financial problems of the developer

Jan 1, 1972

By M Runkel, J Hammerschmidt, A Holmstr÷m, A Charitos, J Gnntner

"Roasting of sulfide concentrates and refractory ores is an important process step in the production of metals and chemicals. Sulfides of iron, zinc, copper and other metals are oxidised with air between 600 and 1000¦C into metal oxides or sulfates and gaseous sulfur dioxide. Roasting of gold concentrates and ores is a typical processing step used to produce a porous calcine suitable for cyanide leaching. During roasting, elements posing problems are removed through: oxidation (carbon, sulfur, arsenic and antimony) or volatilisation (mercury, chlorides and tellurides, as well as arsenic and antimony).This paper focuses on the environmental aspect of roasting using fluidised bed technology. The approach is to show that roasting is an attractive solution for refractory ore pretreatment since, on the one hand, it is an efficient technique yielding high gold recovery rates, while on the other it is able to comply with current stringent international environmental regulations. In that respect, roasting is compared to alternative processes, ie pressure oxidation (POX), bio-oxidation (BIOX) and ultra-fine grinding (UFG). Roaster high gold recovery rates are ensured through roasting-leaching test work, which allows the derivation of respective roasting parameters that are easily achieved in an industrial plant. On the other hand, key elements of the roasting process are analysed, which make it an efficient and sustainable technology, ie the possibility for energy recovery, the removal of off-gas impurities during the different gas cleaning steps (handling of arsenic, mercury emissions and further hazardous dust and gas emissions) and the treatment of the SO2-gas in order to produce sulfuric acid, and finally the treatment of the effluent produced. The processÆs environmental aspects are summarised by listing roasting emission values that comply with international regulations.CITATION:Charitos, A, Runkel, M, Gnntner, J, Holmstr÷m, A and Hammerschmidt, J, 2013. Roasting - a study on environmental aspects, off-gas, effluents and residue treatment, in Proceedings World Gold 2013, pp 509-518 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 26, 2013

By William H. King

The Mining Division of the Bureau of Mines has been making development and power-requirement studios for the Interior Department Missouri Basin Field. Committee. The studies by the Bureau of Mines have as their purpose, the summarizing of potential future power requirements in the mineral industry within the Missouri Basin, special emphasis being placed on possible expansion of these requirements through construction of new mining enterprises by private capital. In preparing a proposal for the production of phosphoric acid from phosphate rock near Lander, Wyo., it was found that the basic information on the physical and chemical characteristics of the phosphate beds to determine costs of mining and treatment was lacking.

Jan 1, 1949

By G. M. Ritcey

The recovery of copper from low-grade solutions res ulting from dump leaching is well known, whereas the recovery from highly concentrated copper solutions has not been practiced. This paper discusses the use of Ashland Chemical's Kelex 100, a substituted quinoline, for the recovery of copper from solutions resulting from leaching copper-nickel concentrates. A flow sheet is described, and an economic comparison shows Kelex 100 to be superior to either the LIX 64N or LIX 70 reagents of General Mills for the recovery of copper.

Jan 1, 1973

By T. A. Sullivan

The use of sulfur combined with either sand or waste copper tailings was investigated by the Bureau of Mines as a substitute for a good graded aggregate in asphalt paving materials. The research was part of a utilization program to develop meaningful uses for a projected oversupply of sulfur. Many sections of the country lack good aggregate for paving but do have available sources of sands and sulfur. The development of paving mixtures of desert sands or tailings with sulfur and asphalt was accomplished in the laboratory and tested by laying small paving test sections. Three types of material were studied for use with the sulfur and asphalt. They were (1) a concrete sand similar in gradation to river or beach sands, (2) desert blow sand, and (3) waste copper tailings. Desert blow sand and waste copper tailings are much finer than concrete sand. Mix designs were established for the three types of materials, sulfur, and asphalt used in the paving materials. The best mix designs were as follows, in weight-percent: 80.5 concrete sand, 13.5 sulfur, and 6 asphalt; and 77 either blow sand or tailings, 17 sulfur, and 6 asphalt. Small-scale testing showed that these mixtures were suitable paving materials but would require specialized equipment for transporting and laying. The chemical modification of sulfur to obtain properties that would allow placement of these materials with normal asphalt paving equipment was studied. Results indicate that reacting sulfur with dicyclopentadiene before adding it to the paving mixture was effective in modifying the sand-sulfur-asphalt paving so it could be placed and rolled with conventional equipment.

Jan 1, 1975

By Russell C. Frith

This paper examines the design of longwall shields, focusing on those aspects that are critical to either their successful application or contribution to failure during longwall extraction. In many instances, longwall shields are assessed and designed along lines similar to that of roadway ground support systems, namely according to typical or normal geotechnical conditions. However it will be contended that for longwall shields, this is inappropriate because unlike roadway ground support systems, longwall shields cannot be supplemented with additional or secondary support in localised areas of adverse geotechnical conditions. In other words, the longwall shield needs to be designed according to what are judged to be worst case or adverse geotechnical conditions?the outcome being that a well-designed shield will be significantly over-rated for the majority of its working life. Therefore, it will be argued that the additional capital cost of such shield design can be readily justified as a prudent riskbased outcome that is essential to minimising future business risks due to strata instability on the longwall face. Shield geometry will be discussed, including such relevant factors as leg angle, inclination of the top caving shield, canopy ratio, operating height range, and tip to face distance. These are all well-established longwall shield design considerations and, most importantly, areas whereby inadequate design can render a longwall shield as highly ineffective. The issue of tip to face distance will be considered in detail, in particular, the extent by which it is an important geotechnical design consideration, the conclusion being reached that, in fact, it is not. The critical importance of maximising set to yield ratio within practical operating limits will be justified, the wisdom of this having been subject to questioning in more recent technical literature. Overall, the aim is to provide the industry with a set of suggested guidelines for future use when designing longwall shields and, hopefully, to initiate discussion on a subject that, unlike roadway ground support design, is not well covered in its entirety in the published technical literature.

Jan 1, 2013

By M. Girgis

The behavior of arsenic III during electrolytic refining of copper in acidic copper ?sulphate electrolytes was studied by different electrochemical methods such as, linear potential sweep, cyclic voltammetry, chronoamperometry and chronopotentiometry. The study showed that arsenic behaves as a depolarizing ion and has a deleterious effect on copper deposit. Three substrates; Pb, Cu and Ag were used during the refining process and the electrode kinetics were found similar for both Cu and Pb electrodes while a little difference was found for the Ag electrode. A microscopic study by scanning electron microscope was undertaken to show the influence of arsenic on deposit's morphology. Surface analyses of the deposit were carried out by some electronspectroscopic techniques such as Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The results showed that arsenic coexists with copper deposit at potential?~ -0.25 V.

Jan 1, 1987

By P. D. Kovscek

The Bureau of Mines equipped a longwall shearer with a water-jet-assisted mechanical cutting system to determine the effect of the high-pressure sprays on machine performance, airborne dust levels generated, and size of particles formed. Testing was conducted on a simu-lated coal block (coalcrete) while cutting at a water pressure of 190 psi and at water-jet-assisted pressures ranging from 1,000 to 6,000 psi. The shearer motor energy used by the shearer while cutting coalcrete was determined for each cutting condition. Results indicate that the motor energy required by the shearer for each ton of material cut did not vary significantly as the water pressure was increased. Results of dust measurements recorded near the cutting drum indicate that at water pressures above 3,000 psi, dust reductions up to 85 pct were achieved com-pared with cutting with conventional sprays. Analysis of the particle size distribution during cutting showed that increasing the water pres-sure resulted in increased median particle size. In light of these results, various mechanisms for water-jet-assisted cutting are discussed.

Jan 1, 1986

By Stephen H. Stow

Economically important heavy minerals have been studied in the sediments of offshore Alabama and Mississippi. Sandy samples have been collected from a 200 square mile area from Dauphin to Horn Islands. The minerals concentrate in sediments under 10-35 feet of water and may reach 2.4% by weight. The distribution of total heavies is related to the hydrodynamics of offshore Alabama-Mississippi; the greatest concentrations are in the Gulf where the longshore current is diverted from its westerly flow. Preliminary observations indicate that the distribution of individual minerals can be correlated with wave energy, particle size, specific gravity, and morphology of the mineral grains. The coarser, lighter minerals--kyanite, sillimanite and staurolite--are concentrated in relatively low energy areas in the Mississippi Sound and at the end of Dauphin Island in the Gulf; maximum concentration for each is 34.5%, 6.0% and 43.2%, respectively, of the heavy minerals. The smaller, more denseminerals--ilmenite, rutile, leucoxene, zircon and monazite--are concentrated in high energy areas in the Gulf; maximum concentration for each, respectively, is 42.0%, 5.9%, 9.652, 10.7% and 1.3% of the heavy minerals. On the basis of a minimum concentration of 1% heavy minerals, two areas have been identified and the total amounts of different minerals have been calculated to a depth of 25 feet of sediment. The data are preliminary and in no way indicate recoverable reserves, but they do show that on the order of 20 million tons of heavies exist. These deposits should be termed "indicated resources".

Jan 1, 1975

By A. G. Darnley

"The Geological Survey of Canada is devoting consider-able effort to finding ways to make airborne radiometric measurements both quantitative and reproducible. Equipment has been designed by Atomic Energy of Canada Ltd. to provide high count rates in order to minimize statistical uncertainty, this being essential to justify applying terrain clearance and Compton scattering corrections to the data. Correction factors have been determined experimentally and can be applied automatically. Considerable ground work has been undertaken in parallel with equip-ment development in order to determine field parameters.Two airborne gamma-ray spectrometers are described. One is based on three 5-by 5-inch Nal(Tl) detector crystals and is used in a helicopter; the other employs twelve 9-by 9-inch detectors and is used from a Skyvan aircraft. The former is being used to investigate the range of radiometric response from specific rock types, and for the correlation of ground and air measurements; the latter has completed initial trials and will be commencing experimental surveys during 1969.Results are given to show the comparative sensitivities of the various detector sizes, and operational requirements for a gamma-ray spectrometer survey are discussed briefly."

Jan 1, 1970