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By Walshe J. M.

The slow-speed compressor is giving place to the high-speed type, with its greater economy of material and space; and, where very large units are required, the turbo-compressor is supplying the need. In the very large air-supply stations on the Rand, turbocompressor units of a capacity of 20,000 and even 50,000 cubic feet, requiring 4,000 to 13,000 horsepower, are quite a commercial proposition, and have proved a practical success. Air-compressors of this size are, however, very exceptional, and the high-speed reciprocating compressor is quite capable of dealing with the highest outputs so far required in this country and, in the hands of manufacturers experienced in the design of high-speed steam-engines, a very high standard of reliability and efficiency in operation is obtained. The so-called “high-speed” or more correctly quick-revolution type of compressor is now extensively used in mines and collieries; for the air-pressures required for power purposes in mining work, two-stage compression, with an intercooler between stages, is the design usually adopted in best practice. It is not the writer’s intention to describe a variety of high-speed air-compressors but to select as an example of this type of compressor the one with which he is most familiar, and which is probably more largely used than any other, namely, the double-acting two-cylinder two-crank type with automatic light-plate air-valves, and with the working parts lubricated on the forced-lubrication principle. Sectional drawings, efficiency curves, air-cylinder diagrams and other data accompany the descriptions and photographs of compressor design, components and mine applications

Dec 1, 1916

By Frederick A. Mumpton

Recent findings by medical workers on the association of certain zeolite minerals with the high incidence of pleural mesothelioma in two small Turkish villages have caused considerable excitement both in medical circles and in the synthetic and natural zeolite businesses. The 42 cases diagnosed between 1970 and 1977 in one community of 600 population in a region of altered volcanic tuff represent a virtual epidemic of this rare malignancy which normally strikes only about one person in a million. Cancer workers around the world expect that detailed environmental and epidemiological studies of the disease in these areas will shed considerable light on the cause of this particularly lethal form of lung cancer. Scientists and engineers developing uses for zeolite materials in industry and agriculture, however, are justly concerned that the preliminary results available on this situation will be used by environmental and regulatory organizations to label an entire group of miner- als as carcinogens on the basis of what is little more than circumstantial evidence. Although there is no question as to the large number of cases of mesothelioma in these areas of central Anatolia, the work to date has suffered from a lack of sound geological and mineralogical input. Ataman (1) stated that a "correlation" exists between mesothelioma and zeolites in this region; however, the geological data needed to document a direct relationship between the presence of zeolites in the volcanic tuffs surrounding the villages in question and the rate of malignant lung disease in the inhabitants have g been obtained, nor has evidence that suggests a cause-effect relationship between zeolites and cancer been reported. To provide fundamental information on the distribution of zeolite minerals in areas of central Turkey where high incidences of pleural mesothelioma have been reported and to evaluate from first-hand knowledge the published reports and news releases of medical workers engaged in assessing the problem, the following investigation was made.

Jan 1, 1979

By R. W. Van Dolah

An investigation was made of the distances over which sympathetic detonation of ammonium nitrate (AN) and ammonium nitrate-fuel oil (AN-FO) might be expected. Large-scale gap tests used two types of AN-FO donor charges in three sizes with AN, both at ambient and elevated temperatures, and AN-FO acceptor charges. Donor sizes were varied to test the validity of a scaling law commonly used in quantity distance tables. The up-and-down experimental design was chosen to determine the 50-percent initiation point efficiently. The acceptor charges were instrumented to indicate initiation and to determine detonation velocity. Other electronic techniques for measuring the rate of growth, stability of detonation, and detonation pressures were employed. Air shock and fragment velocities between charges were measured by electronic and photographic methods, and determination of side-on air-blast pressures and impulse duration were made for about half the shots. Separation distances between donor and acceptor were found to be larger than anticipated both for the AN and the AN-FO. With AN-FO acceptors and a 16-gage steel faced donor, one initiation occurred at a separation of 53 feet or nearly 16-charge diameters; with AN, initiation occurred at 4 to 5-1/2- charge diameters.

Jan 1, 1966

By Don Welch

Pressures for change ?Land use constraints ?Project financing ?Local communities ?Environmental issues ?Sustainability requirements ?Stricter regulatory procedures ?Technical excellence ?Reduce risk ?Impacts of failure & non-compliance

May 1, 2010

By Donald Giroux

This report documents the design, fabrication, testing, and coal mine demonstration of a hopper-feeder-bolter during a four-phase program for the U.S. Bureau of Mines. The machine was designed to increase productivity and safety in under-ground room-and-pillar mining. It performed well as a hopper-feeder for continuous haulage during a coal mine demonstration. Testing in a simulated mine showed that the machine also has good roof bolting capability.

Jan 1, 1987

By Ryan Law

Ground energy systems are being installed in increasing numbers in the United Kingdom. This is particularly true in London where planning regulations require larger scale developments to provide at least 10% of their entire energy demands from renewable sources. A common approach has been to use the groundwater from the Chalk aquifer as a source of energy. This paper explains the potential long and short term sustainability problems with groundwater based systems sited in central London (or any other urbanized area). It also outlines an approach to site testing and numerical modelling to ensure that the system functions well throughout its lifetime. This approach is then applied to a project located in central London.

Jan 1, 2008

By J .. F. Brownrigg

In the mining method used at O'Okiep Copper Company (OCC), vertical crater retreat, the prime requirement for the fill is that it should be sufficiently strong to be free-standing to a height of 150 m. Other requirements are minimal decant and drainage water, and high pulp density to allow large tonnages to be placed quickly and alleviate transport problems. The excessively high cost of cement precluded the use of a cement-based fill, and after three years of extensive investigations a backfill based on the smelter slag was produced. Currently a fill with a uniaxial compressive strength of greater than 1 000 kPa after one month is being produced. This is in excess of the design specification of 850 kPa after 2 - 3 months. The research and development which went into the slagfill is briefly covered; the production of the fill from the various raw materials is described; and the design and control systems of the backfill plant, the reticulation system and its monitoring are examined. Finally, the implications of this high- quality fill for the mining programme are assessed.

Jan 1, 1988

By G M. Mudd

The growing popularity of platinum and platinum group metals (or PGMs, including palladium, rhodium and others) for a wide range of applications leads to some interesting issues for mining and sustainability. The uses for PGMs includes catalytic converters for air pollution control in vehicles, growing jewellery use, catalysts for various purposes (especially petroleum and chemicals processing), hydrogen fuel cells and many others. Given the growing importance of most of these PGM uses in more sustainable technologies or in making industrial processes more efficient, it is critical to understand the complex sustainability issues which surround platinum and PGMs. At present, South Africa is the dominant PGMs producer and holds about 88 per cent of estimated global resources, with important but relatively minor production and resources in Zimbabwe, Russia, Canada and the United States. Given the concentrated location of PGM resources, what are the likely trends in PGM mining with respect to environmental sustainability? That is, what are the costs in terms of energy, pollution, greenhouse gas emissions, water, land use impacts, social impacts, economic aspects associated with this globally important industry? This paper compiles and analyses a range of data on platinum-PGM mining, focusing primarily on South Africa. It synthesises a unique combination of data which relates typical production aspects such as ore grade and scale with sustainability aspects such as greenhouse, energy and water costs. The findings are critical in understanding the debate about the increasing environmental and social costs of some materials and technologies which are considered crucial for sustainable industries based on PGMs. Overall, the paper represents a valuable insight into the platinum-PGM sector, providing a range of useful data for understanding the environmental sustainability of this particular group of precious metals.

Jan 1, 2009

By T. D. Chatwin

While new jobs and taxes are major incentives for support of mining, stakeholders must also be assured that current jobs, resources and environment will be protected. Mining companies can help achieve stakeholder support by frankly addressing Acid Rock Drainage CARD) issues. To prevent ARD, miners must begin early in the mine life-cycle to develop an ARD management plan and integrate it into the mining operation. As this proactive preventative program is initiated, mining companies also need to engage and collaborate with stakeholders to insure that their expectations and needs are met. Stakeholder engagement is enhanced as mining companies emphasizes the value of clean and available water for current and future generations.

Jan 1, 2011

By Ralph H. Cleland

Introduction The mines of northern Ontario have entered the class of deep mines. It has often been asked: How deep can operations be carried on? What will the temperature be? This paper is a résumé of a brief survey of rock temperatures made by the Ontario Department of Mines during the year 1932. Present temperatures were recorded and the geothermal gradients that now exist were determined. No alarming situations were found, but many interesting ones have been noted. Northern Ontario mines are fortunately situated as compared with most deep-level mines of the world. The mean yearly temperature, as determined from meteorological records of the Federal Department of Marine, is from 33 to 38 degrees Fahrenheit. The tables on the next page show the temperature range in and about our mining camps ( l ). As no exact figures were obtainable for Kirkland Lake, the data for Iroquois Falls, which is about 50 miles northwest, were taken as applicable there. The figures for Timmins were checked against those of Cochrane and Iroquois Falls and found to be very similar, so that the Cochrane data may be used for the Porcupine camp. The yearly mean temperature is considered to be 33.5 F.

Jan 1, 1933

By I Gipps

Each of us has a vision of what the future mine will be and, generally, these visions have many similarities and some differences. One of the major discrepancies in visions of the future mine is not the ultimate goal but the path to achieve it. Many of the future concepts require a radical re-thinking of how things are and will be done yet. So how do we reach this visionary future mine? We need a path that satisfies both our future aspirations of a high tech gee-whiz operated from our iPads and the unfortunately mundane approach that says ‘we must know the method works, ie nothing new’.This paper explores how, within a research based organisation, we firstly set our ultimate goal and then divide the path into realistic technology development chunks that would appeal to mining companies to progress within their organisational constraints. Through examples, such as, automated LHDs, communications systems, surveying and localisation, rock cutting and geological sensing, we illustrate how this path will get us from the here and now to the out there future.This paper also demonstrates CSIRO’s short, medium and long-term research in many of the areas needed to create the Future Mine: mining methods, automation and remote control, mine communications, mapping and mission planning, geological sensing and, importantly, human-system integration, which examines how to effectively present data as information to operators and supervisors in an intelligent and useful manner.

Nov 22, 2011

By T O Aspinall

The Australian mineral industry involves a diverse range of expertise and skills. Within that, the mining industry, representing mine planning, mine management and equipment operation, has capital intensive, high productivity equipment and a small but skilled workforce. Continuing education for all personnel in the workforce after formal school courses will be an important contribution towards improving competitiveness. The non-tertiary sector represents a significant proportion of the workforce and requires as much attention as the tertiary educated group. Competency Based Training is now being developed for the mining industry in Australia under the National Training Board and the mining industry is well represented in establishing standards and curriculum. TAFE is a major source of accredited courses but some mining companies are also developing internal courses not necessarily for external accreditation. Articulation of such accredited courses to tertiary mining engineering courses has been considered. The education and training of equipment operators through continuing education requires attention to operating skills, an understanding of the productivity factors under the direct influence of the operator and providing product quality to the customer. The education and training of mining engineers has been widely covered and continuing close involvement of the mining industry is required to ensure well balanced courses in technical and interpersonal skills as well as motivation to continue learning for life. Postgraduate research is a part of continuing education but the mining industry has to continually address the adequate recognition of post-graduate qualifications for the increased technical or management expertise and the development of better analytical and problem solving skills which can be directed towards improving competitiveness. More attention has to be paid to providing adequate financial incentives to attract suitable students, particularly after attaining some experience, and to address their professional career path with a company so they are not significantly disadvantaged by undertaking post-graduate studies. The Chartered Professional Engineer status as provided by The Institution of Engineers, Australia to qualified candidates is being considered by The Australasian Institute of Mining and Metallurgy as a further recognition of a member's specific expertise and competence in mining and metallurgical engineering. Continuing education plays a major part in the maintenance of the expertise and competence required for a professional engineer to develop and also to retain chartered status. Continuing education will be a significant part of the education and training of all the mining workforce towards improving the competitiveness of the mining industry. The major challenges will be the motivation of all towards lifelong learning and the integration of the various programs towards providing the opportunity for a steady and satisfying career progression.

Jan 1, 1994

By Lucien Piché

"IN any opportunity such as I am now given, I suppose that one should not fail to say that what the world has to offer to this year's graduates in science and in engineering is the greatest promise ever held out. High-ranking new scientists and engineers -particularly those with the Ph.D. degree -find themselves in an apparently delightful situation; the glow of attention that surrounds them and the dazzling starting salaries that are offered to them may indeed be turning their heads a bit and the attitudes of some of them are sometimes expressed with a smugness that can find its equivalent only in freshmen. On the average, however, the new graduates are, without any doubt, the best trained ever, or at least they have been the most expensive to train in the universities.There appear to be exciting opportunities for competent, well-trained and educated scientists and engineers far beyond the numbers that can be annually produced, and the demands for excellence in depth as well as in breadth of training probably will continue to increase for many years to come. The problem is visible all around us in Canada that there is much more money to buy brains than there are brains to be bought."

Jan 1, 1966

By Gonzalo Díaz, Diego Mesa, Willy Kracht

"It is well known that frothers affect the amount of water that is transferred to the froth, which has an effect on both the froth stability and the water recovery. On the other hand, since non-selective recovery by entrainment is directly related to water recovery, it can be said that frothers have an indirect effect on flotation selectivity. Recent research on this subject has shown that the non-selective recovery by entrainment, which is characterized by the entrainment factor, is frother dependent. In other words, the entrainment factor is not unique, but depends on frother type.Having different entrainment factors implies that for the same water recovery, the amount of undesired particles reporting to the concentrate may vary if one changes the frother type, which suggests, as a possible explanation, that it is not only the amount of water in the froth what is affected by frother type, but also the froth structure.The purpose of the current work is to study the effect of frother type on foam structure (two phase froth). A quasi-2D cell operated with a slot sparger was used to study the foam structure in the presence of three different frothers: Methyl Isobutyl Carbinol (MIBC), OrePrep®549, and Octanol at the same gas flow rate and reagent dosage. The foam structure was studied using image analysis, and an algorithm based on textural analysis was developed to classify the foams. The results show that it is possible to classify foams according to the frother used, which proves that frothers have an effect on the foam structure.INTRODUCTIONFrothers are usually dosed paying attention to froth stability, condition that is commonly estimated by sight, according to the operator's criteria and experience. This happens because there is not an established procedure or technique for frother characterization, generating qualitative descriptions such as “powerful” or “selective” frothers, which lack of scientific thoroughness and remain under subjective factors. Nevertheless, several works have been done in this line of research. Moyo et al. (2007) classified frothers based on their water-carrying capacity, proving that this characteristic is related with gas holdup and frother type. Previously, Trahar (1981) had related water recovery and gangue particles recovery, defining the entrainment value (ENT). Nowadays it is known that entrainment affects both hydrophilic and hydrophobic because it is not a selective process. In the last decade some studies (for example the one of Konopacka and Drzymala (2010)) delved into different entrainment behaviours dependent mainly on the flotation type (batch or continuous, agitated or columnar, etc.), but there were no studies on the effect of frother type regarding entrainment, since Rahal et al. (2001) argued that the ENT factor was independent of the frother type and concentration, and froth height."

Jan 1, 2016

By Michael D. Balen

This Bureau of Mines open file report is one in a series of reports written about the Valdez Creek Mining District (VCM D) as a result of the continuing Bureau of Mines mining district evaluation program. This report presents the results of order-of-magnitude mining feasibility studies. The mining feasibility studies were conducted for mineral deposit models that were based on real and hypothetical deposits that occur in the VCMD. A total of 6b mine models were developed for application to the mineral deposit models. The goal of the feasibility study was to determine the monetary value per unit of minable ore that would cause the simulated cash flow for each of 66 mine models to achieve certain pre-defined rates of return for the invested capital.

Jan 1, 2011

By V. H. Valenzuela

Materials in process or in stocks are quite relevant items in almost every plant, particularly in mining operations, where efficiency in rate of recovering material of interest becomes a key issue when production costs are evaluated. A manager requires information to do an effective use of the resources, especially when raw materials are involved. Losses associated to leaking, efficiency in the transformation process, performance of equipment, and operating conditions are a short list of items which must be properly identified and evaluated. Operations supervisors require information in order to keep key process variables under control. Because of these information needs, it is absolutely necessary to carry on a series of activities related with installation and maintenance of measuring equipment, sampling equipment, sample preparation, chemical analysis, statistical analysis, data handling and reports generation. These pieces of data must be managed on a wise manner in order to get the most of it, keeping always on mind data reliability. Normally, information related with metallurgical balance and even more, the metallurgical balance concept, is handled under an accounting criteria which does not allow dealing with the real world. This situation happens because the criteria utilized do not consider aspects such as bias and uncertainty associated with every measurement that affect the quality of the information and therefore conclusions drawn from it. The purpose of this paper is to give a few rules, necessary to follow, in order to develop an adequate Metallurgical Balance System for an operational point of view. The Gaussian approach for error propagation is used as a basis, allowing one to know the actual uncertainty of the balance and the way how it can be improved. A few real applications of this concept are listed, detailing experiences obtained from practice.

Jan 1, 2007

By Simon C. Dominy, Alwyn E. Annels, Paul Wheeler, Suzanne P. Barr, G. Simon Camm

Narrow veins are an important world-wide source of silver, tin, uranium and particularly gold. To potential ?nanciers, this style of mineralization is viewed as high risk because of the often relatively small resource involved and high cost of estimation. In many cases diamond core drilling will not enable resource estimation beyond the inferred and indicated categories. Exploratory under-ground development is required to de?ne measured resources. The de?nition of geological and grade continuity are major factors in narrow vein assessment. A measured resource must be based on strong geological and grade continuities. Narrow veins, generally less than 3 m wide, are complex geological phenomena, which commonly display unpredictable geometry and grade distribution. Variations in structural continuity, dip, strike, width, mineralogy and speci?c gravity are common. Veins may be composite, with ore-grade mineralization restricted to a speci?c structural domain. Branches, intersections and braided zones are common features. Potentially high-grade zones are often localized within ore shoots, which are surrounded by barren/low-grade regions. Resources must be determined as closely as possible to reality and re?ect the distribution of the commodity in the rock. Estimation has three main requirements: (1) geological study to determine orebody nature;(2) estimation of tonnage and grade, and (3) the presentation of this information using a classi?cation that is clear, unambiguous and bankable. Estimation methods employed are either classical or geostatistical; however, classical methods are often used because of the dif?culties in applying geo-statistics. Grades generally show a strong positively skewed distribution testifying the presence of high-grade values. Problems exist in the applicability of cutting outlier values risking over- or under-estimation of grade. It is generally believed that where resource estimates are in error, poor geological control is usually the cause. Overestimation can lead to the closure of a mine through lost revenue and capital. An understated estimate can result in an opportunity missed for pro?t and/or greater economies of scale. De?nition of reserves involves the consideration of economic and engineering data, to decide which part of the resource is economically mineable. Geology plays a similarly important role at this stage in the assessment of likely mining method, dilution, recovery etc. Throughout resource/reserve estimation, it is crucial that the amount and quality of the data and the geologist’s experience are relevant. The impact of geological understanding on estimation is often undervalued or assumed to be of lesser importance than ?nding grades and tonnages. This paper discusses the geology of narrow vein deposits and the importance of geology in their evaluation.

Jan 1, 1997

By T. A. Lang

Concepts and equations have been developed to quantitatively determine the stability of a rock bolted coal mine roof as a structural (beam-arch) member consisting of reinforced rock units. The equations take into account: rock bolt tension, length, spacing, and orientation; size of opening, strength and physical properties of the rock; and loads from distressed rock, and were critically reviewed using sensitivity analyses and the results available from relevant previous analytical and physical model investigations. It is concluded that they can essentially be validated by using small scale physical models and the full size mine entry model at the USBM Spokane Research Center. However, a comprehensive research program, including analytical and laboratory investigations and field trials in typical mines, will be required to define and validate criteria and standards for using the equations as a basis for a rational design code for rock reinforcement installations to replace the semi-empirical rules now being used. For example, these studies have shown that the practice of installing vertical roof bolts with a uniform spacing equal to the bolt length is inherently unsafe and that the spacing should be reduced near the walls to prevent shear failure of the roof strata. The development of such a rational design code would provide enhanced safety in coal mining operations and warrants a high priority in the Bureau's ground control research program.

Jan 1, 1981

By Jafar Safarian, Leiv Kolbeinsen, Stian Seim, Hossein Salehi

The present work aims to investigate the link between the oxidation and reduction of a weathered ilmenite concentrate in terms of phase transitions, microstructural changes, and element distribution. An ilmenite concentrate sample was pelletized and fired at 1000 °C in air, and as a result, the pellets were oxidized. The oxidized pellets were reduced by hydrogen gas at 1000 °C, which yielded almost complete metallization of the iron content of the pellets. The ore and the pellets were characterized in each step by XRD and SEM techniques, and distribution of elements and phases were investigated. Ilmenite, pseudorutile, and rutile were the main phases detected in the ilmenite concentrate sample, and depending on the weathering degree of the particles, different fractions of the phases were identified in their microstructure. It was found that irregular rutile grains dispersed in a pseudobrookite matrix is the morphology of the oxidized ilmenite phase. However, increasing microcracks and porosities were the only microstructural changes in the pseudorutile phase after oxidation in air. Studying the specific types of the ore particles and their oxidized and reduced forms indicated that the phase distribution in the ilmenite ore particles dictates the phase distribution in the oxidized and reduced ones. Results show that the morphology of the reduced particles includes a titanium (III) oxide matrix in which reduced iron globules are dispersed.

Feb 8, 2021

By Joshua Micah Hoffman

While it is easy to state that meaningful involvement of the community can play a critical role for a successful blasting operation, following through with this involvement is not an easy task. Structured Public Involvement (SPI) is a developed protocol for involving communities in project planning decisions and could be readily applied to the blasting industry. SPI was developed for the purpose of collecting quality public input about public transportation projects. The purpose of SPI is to bring about stakeholder satisfaction with potential projects by allowing controlled input from the stakeholders. It was designed and intended for democratic societies that have come to expect a voice in public projects. While blasting operations are not always in the domain of public projects, the fundamental process outlined by SPI can be useful for collecting feedback from the immediate public around blasting operations.

Jan 1, 2014