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By K. Schonert

Jigging is a separtion process that has already been described by Agricola in 1556. Fine size material is normally treated in a hutch jigging process, in which the heavy particles are penetrating the jigging bed and are recovered in the hutch. In this process, a ragging consisting of the same or higher specific gravity particles is inserted upon the screen. The ragging is used mainly as a valve to maintain a constant upward flow of the water. Since the heavy particles should pass easily into the hutch, the ragging particles are up to ten times larger than the maximum feed size (1). In the fine size range - 1 mm the performance of jigs is mainly insufficient; some of the low density particles percolate the ragging while the hutch water flow prevents the fine heavy particles from entering the bed (2). By giving a thin layer of particles, which posesses a density sensitivity in case of certain adjustment of flow conditions, directly on the screen, the precision of separation can be increased. Stroke length and frequency have to be adjusted to give this filter layer a homogenous porosity between 60 and 70% during the pulsion phase, and the "en masse" lifting of the bed, as it is known in jigging of coarser material, has to be prevented (3). In this case, the jig cycle is only of minor influence.

Jan 1, 1987

By J. F. Liu, L. Chen, C. P. Wang

"Calcite-cemented joints abound in the rock masses of Beishan area, which is the most potential area for the high-level radioactive waste (HLW) disposal of China. The mechanical properties of Beishan granite containing a calcite-cemented joint with a dip angle of 82° was investigated under uniaxial compression and the acoustic emission (AE) characteristics were also studied in this paper. Compared to intact granite, the calcite-cemented joint caused a decrease more than 50% in uniaxial compressive strength and a decrease more than 90% in shear strength. The Young’s modulus was also decreased, while the circumferential deformation of jointed granite was sharply increased. The AE monitoring system successfully recorded the process of micro-crack development and the results indicated that the risk of rock-burst could be reduced due to the appearance of calcite-cemented joint.INTRODUCTIONThe properties of jointed rocks differ considerably from that of intact rock. Due to the difficulties in specimen preparation, analogue experiments with artificially prefabricated fractures are often used to study the mechanical behavior of jointed rock (Chen et al. 2012; Kulatilake et al. 2001; Singh et al. 2001). However, natural joints are not quite similar to the artificial fractures and it is necessary to investigate the mechanical behavior of jointed rocks. Xie et al. 2011 studied the mechanical properties of marbles with natural joints by uniaxial compression tests and found that the uniaxial compressive strength of jointed rock is greatly decreased. With the unaxial compression tests, Jacobsson 2005, 2007 tested the intact and jointed granites, which were taken from the potential site for high-level radioactive waste (HLW) disposal of Sweden. However, no significant difference in strength or modulus was found. The above research results are inconsistent and it indicates the complexity of the mechanical properties of natural joints."

Jan 1, 2015

By Joseph F. Peters

The paper will begin with the physical parameters of design in a wire saw. These will include such things as the type of wire used, abrasives, horsepower of operation, and drive components. It will then go into the many uses of wire sawing in the quarrying and finishing of granite. This will include a step by step program of the removal of a block unit of granite from the quarry site through the finished slabbing and jointing in the plant. After this, there will be a small insertion of possibilities of wire sawing techniques in underground excavation work. This would be speculative only. I will use the example of powerhouse type of excavation work given to me by Dr. John Reed, and try to explain how I would attack this type of work using wire saws. Several slides of both design criteria and actual installations were shown.

Jan 1, 1997

By V. Rajaram

The Parachute Creek Member of the Green River Formation in the Piceance Basin, Colorado, contains vast reserves of oil shale, nahcolite, dawsonite, and other accessory minerals. The dry alkali process of sulfur dioxide removal using nahcolite (naturally occurring sodium bicarbonate) has great potential. A room and pillar mining scheme has been designed to extract a nahcolite zone occurring at a depth of 472 m, from the lease application area of the Yankee Gulch Joint Venture. Geotechnical parameters affecting mine design will be discussed. A preliminary development plan for mining at the rate of 1000 t/d will be described in detail.

Jan 1, 1977

By Steve Kral

In recent years, junior mining companies, mostly listed in Canada, have taken a beating in the finance markets. Simply put, potential investors have been leery of sinking millions into exploration and mining projects due to volatile commodities prices and an uncertain regulatory climate in developed and developing countries. The 2014 edition of the Prospectors and Developers Association of Canada (PDAC), however, seemed to be a bit different for some juniors. Equity valuations have improved and metals prices appear to be stabilizing. So, for some of the stronger junior companies, there is some hope. Merger and acquisition (M&A) activity is picking up and, believe it or not, companies are raising some capital. Billed as the largest annual mining meeting in North America, the PDAC conference attracted more than 25,000 mining and exploration professionals from around the world. Organizers were anticipating attendance to break the 30,000 mark. But, given the state of the exploration end of the mining business, 25,000 is still a respectable number. Junior companies that are in the project feasibility stage, or have made promising discoveries that stand a good chance of proceeding to production, are being looked at by potential investors. Those are the survivors of the last three years of dismal M&A activity. On the other side are the juniors that are still around ? and there are plenty of juniors that were at the PDAC last year but have since disappeared ? but have little or no working capital. One analyst calculated that there are about 850 companies with less than $200,000 in working capital and about 600 with negative working capital. This will likely result in fewer junior mining and exploration companies as the year progresses but the ones that remain should be stronger.

By Crystal Poon, Paul Matlashewski, John Morkeh, Kathryn Dorfschmidt, Jose Carvalho, Chad Williams

Rockfall hazards are ubiquitous in mining environments making their control critical for safe mining operations. The complex processes involved in rockfall events necessitate a probabilistic modeling approach with well-calibrated material properties. The controls designed to mitigate rockfall hazards need to be reliable, efficient, and safe to deploy to meet the constraints present at an active mine. This paper presents an innovative solution to rockfall at Rio Tinto’s Bingham Canyon Mine. The solution incorporates the site-specific calibration and creation of a predictive rockfall model with the design, field testing, implementation, and monitoring of the rockfall controls.

By M-d-N. Gagnon, P. Okono, Y. Bergeron

In the mining industry, decisions regarding the type and number of comminution tests to be completed typically rely on geologists? observations and conclusions when studying drill cores. Given that these decisions are based on visual observations, they are essentially approximate and often inaccurate from a comminution viewpoint, causing a sizeable margin of error in estimating characterization test needs. Consequently, companies are often forced to perform more tests than necessary, requiring a significant quantity of material, and accruing significant costs. Recently, a new device, called the Hardness Index Tester (or HIT), was developed, offering users a low cost in-house mechanism for estimating the comminution parameter A*b and the Bond Ball Mill Work Index at any mine site, with potential applications on fragments up to 25 mm from drill core. In late 2016, Agnico Eagle Mines Limited initiated a trial to investigate if having an HIT device installed in a core repository would make it possible to identify the different rock properties more accurately and determine the number and type of comminution tests required. The application of the HIT was not to replace the standard comminution tests, but rather to generate a high number of comminution and geomechanical parameters for the rock mass. Ultimately, the objective would be to determine the uniformity of the rock mass and, therefore, easily distinguish any potentially problematic zones. With this method, the appropriate number of standard tests could be determined, making the HIT not only an excellent complement to the standard laboratory tests, but also an indispensable device for a geometallurgical characterization. This paper presents the results from the HIT trial using samples from the Odyssey Project, which is a Mine Canadian Malartic property.

Jan 1, 2017

By W. Kunda

A laboratory study was carried out on the treatment of sulphidic copper concentrates in aqueous chloride systems under elevated temperatures and oxygen overpressure. Exploratory tests showed that chalcopyriteoxidizes with various chloride salts to form, depending upon the pH of the system, soluble copper chloride or insoluble copper oxychloride salts; the copper can then readily be recovered from the solution or residues respectively. During the leaching, iron was oxidized to iron oxide and remained in the leach residue while the bulk of the sulphide sulphur was oxidized to the elemental form with a minor portion oxidized further to sulphate. The presence of metal chloride salts in the system increased the oxidation rates of chalcopyrite and depressed the solubilization of iron in the system. A systematic oxidation leach study carried out in (1) ammonium chloride and (2) sodium chloride systems showed that the former system required little or no HC1 addition while the latter required 2 mol of HC1 per mol of dissolved copper (plus zinc). The copper was recovered from the cuprous or cupric chloride leach solutions by cementation with iron. Extractions of 99% copper and zinc, 97% silver, and negligible iron were obtained. Sulphur was oxidized to the elemental or sulphate form; the relative proportions of the total sulphur were 60 and 30% for system (1) and 80 and 10% for system (2). A flowsheet for a conceptual process with minimal reagent requirements was proposed.

Jan 1, 1976

Poor floatability of fine particles is known to be the main cause of the low recovery of ilmenite in Panzhihua, which is the largest titanium mine of China. To get an optimum ilmenite recovery, selective flocculation, and flotation of fine ilmenite was investigated through flotation tests, particle size analysis, zeta potential tests and scanning electron microscopy. The results indicate that carboxymethyl cellulose (CMC) shows flocculation effect for both ilmenite and titanaugite without selectivity, while selective flocculation could be realized by the combination of water glass and CMC. It is because that competitive adsorption would take place on these two kinds of mineral when water glass and CMC are used together. On the surface of ilmenite, the adsorption ability of CMC is stronger than that of water glass, so that CMC can absorb to the same extent irrespective of the presence of a pre-adsorbed layer of water glass and ilmenite particles is flocculated by CMC. The same cannot be said of the titanaugite phase as water glass strongly adsorbs onto the titanaugite, and the adsorption of CMC is hindered. Therefore, the titanaugite particles keep dispersion. Furthermore, the flotation of fine ilmenite particles is feasible as the ilmenite floccules could react with sodium oleate. In the flotation separation of Panzhihua ilmenite ore, the recovery of TiO2 increased from 52.63% to 68.28% by selective flotation. Keywords: ilmenite, flotation, selective flocculation, adsorption

Sep 1, 2012

By C. Peter Hayes

The world continues to change and with it the supply of minerals and metals, the location of centres of production of primary metal and the increasing levels of metals and materials recycling. New technologies are being developed to meet the ongoing search by industry for lower costs, cleaner production and new markets. To keep abreast with these changes, and to utilise fully, the potential benefits of these technical advances, the industry will need a professional workforce having different knowledge, skills and professional attributes than in the previous millennium. What are these skills and attributes? How to best attract and develop the metallurgists of the future, and provide for the ongoing educational and research needs of the industry?

By J Webb

The mining industry is relatively niche and complex compared to other global industries in its safety and operating environment. Whilst some of the technology required to decarbonise the mining industry will emerge from the mass market (eg batteries, energy storage solutions and renewable power generation) where exogeneous external investment and innovation will drive supply, bespoke applications such as material movement will be constrained by industry limitations. Underground load and haul equipment burns the majority portion of underground mine diesel, and typically 25 per cent of scope one and two emissions. Transitioning away from incumbent diesel engines offers a considerable health benefit to all mine workers, as well as decarbonisation achievements, and through trials there is emerging evidence of more productive equipment and realistic expectations of lower operating costs of fleet. However, new equipment and material movement systems that support these industry goals are currently approached with caution due to the pivotal role they play in delivering productivity goals, and the lack of experiential data and certainty to mitigate the supplier development risk during this technology transition period, where all resources are required to meet a booming industry. A group of mining companies and suppliers have the aligned aim to accelerate the understanding and availability of heavy haulage mobile equipment through collaboratively piloting equipment and working with suppliers and each other to aggregate market demand, encourage investment and resolve the mine design and technology choices through their involvement in the Electric Mine Consortium (EMC). This paper will outline the major challenges the industry must overcome in sourcing and adopting a zero-diesel particulate and zero-emission mine, drawn from cases and insights across ten EMC mining company members.

Mar 29, 2023

By B. Yu, S. Kelebek, C. Gibson, M. Aghamirian

There are a number of high grade niobium deposits worldwide which have been deemed untreatable by flotation due to the very fine grained nature of the in situ pyrochlore, the primary niobium bearing mineral. A known method of recovering extremely fine particles is through the use of chelating reagents such as hydroxamic acids which have a strong affinity for transition metals. However, one of the major issues in the flotation of niobium bearing minerals using hydroxamic acids is the corresponding recovery of other transition metal gangue minerals including magnetite, hematite, and pyrite. In order to better understand the differences in behavior of niobium and iron bearing minerals in flotation with benzohydroxamic acid (BHA) and sodium hexametaphosphate (SHMP) at a range of pulp temperatures, a Box-Behnken experimental design was employed. Regression models for the global recovery of iron indicated that iron mineral recovery was significantly influenced by both BHA and SHMP dosage. Upon examinination of flotation products by semi-quantitative XRD, it was observed that recovery of iron oxide and sulphide minerals (hematite, magnetite, goethite, and pyrite) was problematic at high benzohydroxamic acid dosage, while sodium hexametaphosphate was mainly helpful for carbonate mineral depression. Iron rich carbonates (likely an iron rich dolomite) largely reported to the tails with increased SHMP dosage.

Jan 1, 2015

By Guoqiang Lan, Jun Song, Bin Ouyang

Rare-earth pyrochlores, commonly exhibiting anomalously low lattice thermal conductivities, are considered as promising topcoat materials for thermal barrier coatings. However the structural origin underlying their low thermal conductivities remain unclear. In the present study, we investigated the phonon properties of a group of RE pyrochlores, Ln2Zr2O7 (Ln = La, Nd, Sm, Gd) employing density functional theory and quasi harmonic approximation. Through the relaxation time approximation (RTA) with Debye model, the thermal conductivities of those RE pyrochlores were predicted, showing good agreement with experimental measurements. The low thermal conductivities of RE pyrochlores were shown to largely come from the interference between the low-lying optical branches and acoustic branches. The structural origin underlying the low-lying optical branches was then clarified.

Jan 1, 2015

By W. H. Andrews

DEFINITION OF BAUXITE The term "bauxite" (1) dates back to 1821, when it was assigned to a deposit of red earthy material outcropping near the village of Les Baux in Southern France. Chemical analysis indicated the presence of aluminium oxide, iron oxide and water. Deposits of bauxite are widespread throughout the world although the major developments occur within 30 degrees of the Equator. Essentially bauxite is the product of weathering and leaching of a variety of sediments or rocks, generally in a high-rainfall tropical or sub-tropical climate, resulting in the enrichment of the aluminium oxide content. It is characterised by the presence of one or more of the minerals, gibbsite, boehmite, and diaspore. The other constituents are usually clay, (typically kaolin), hematite and/or goethite (iron-oxides), anatase (titanium oxide), and possibly silica as quartz. A variety of minor elements may be present, such as calcium, magnesium, phosphorus, vanadium, gallium, manganese, and many others in very small quantities. Organic compounds are normally present from development in association with a soil horizon where vegetation may be encouraged by the high rainfall necessary for bauxitisition. The physical form depends upon the geological history of the deposit and correlation also exists with the mineralogy. Older deposits which have been subject to burial are invariably hard and compact with the alumina predominantly occurring as boehmite or diaspore, while the more recent, surface deposits are frequently less compacted and gibbsite is the dominant alumina mineral. In these later deposits, the physical form can vary from the fine red soil (terra rosa) of Jamaica to the Weipa pisolites to the cemented Arkansas type. The presence of concretionary structures is an important aid in identification in the field.

Jan 1, 1984

By A. V. Wilke

The metallurgical balance is a tool usually applied in the mining industry. The final result is used for different objectives. All the existing software for the calculation of the metallurgical balance fits the numbers in such way that a logical correspondence between the input and output materials exist. Nevertheless, the accuracy of the metallurgical balance strongly depends on the quality of the input data. Division El Teniente of Codelco Chile has been optimizing the metallurgical balance system the last 14 years. As well, it has participated in the development of corporate norms to optimize the operations of sampling and weighting systems. As a consequence, the precision and the accuracy of the metallurgical balance have been improved in a significant way. Also the understanding of process variability was enhanced. The improvements have allowed Codelco to discover and minimize hidden losses and to better support top management decisions. The present paper describes the main aspect of the continuous improvement process.

Jan 1, 2009

By Jorge Acosta Ale

"El presente texto señala la perspectiva de la producción peruana de cobre para la próxima década y su aporte económico en el Perú a través de un cuadro estadístico donde se observa un incremento de los pórfidos de Cuajone y Cerro verde en los años 70´, skarn de Tintaya en los 80´ y Antamina en el 2001. Así también se revisa el canon minero, regalías mineros y derechos de vigencia. "

Dec 1, 2016

By B. Crane, S. Schwartz

"IntroductionThe Cape Breton Development Corporation (CBDC) located in Cape Breton, Nova Scotia, in eastern Canada, was established in 1967. Its mandate at that time was to facilitate a phased downsizing of the coal industry and developing viable replacement industries. The oil crisis in the early 1970s changed CBDC’s mandate and focus was modified to increase coal production to support Nova Scotia Power Commission’s “off oil” policy for their power generators. In the late 1980s the mandate to develop viable replacement industries was eliminated and CBDC became primarily a coal mining company. CBDC presently operates two underground coal mines, Phalen Colliery and Prince Colliery, using a retreat longwall method of mining. Both mines operate beneath the Atlantic Ocean. CBDC also operates associated infrastructure — central workshops, a railroad, coal preparation plant, and international pier. The Need For Substantial ChangeOver the last few years, CBDC has been facing some challenging issues, including improving labour management relations and achieving financial self-sufficiency and profitability. Recent achievements with regard to human resource issues, especially in the areas of collective bargaining, absenteeism, and attendance, show noticeable improvements. All participants should be commended for successfully concluding the collective bargaining process with all four CBDC unions, CUPE; CAW; IAM&AW; and UMWA. However, although these changes are encouraging, even critical in the short term, they are not sufficient to ensure the long-term viability of the company. Market ForcesShort- and long-term financial realities are drawing the need for further substantive changes. The corporation has a mandate to achieve financial self-sufficiency by the year 1999. This goal can only be achieved through a combination of cost reductions and productivity gains, specifically, a reduction in the workforce of 658 and an increase in production of 800 000 tonnes annually. This increase in productivity requires CBDC to re-think the way it does things.In the longer term, CBDC faces even greater challenges. The energy market is becoming more competitive. The electrical utilities across Canada are anticipating deregulation and are positioning themselves for the resultant competition. As primary fuel supplier to Nova Scotia Power Inc. (NSPI), the corporation will have to become ever more competitive to stay in business."

Jan 1, 1997

By A. Miller, M. McNinch, R. Jacksha

Each year, hundreds of mine workers are involved in machinery-related accidents. Many of these accidents involve inadequate or improper use of lockout/tagout (LOTO) procedures. To mitigate the occurrence of these accidents, new safety methods are needed to monitor access to hazardous areas around operating machinery, improve documentation/monitoring of maintenance that requires shutdown of the machinery, and prevent unexpected startup or movement during machine maintenance activities. The U.S. National Institute for Occupational Safety and Health (NIOSH) is currently researching the application of Internet of Things (IoT) technologies to provide intelligent machine monitoring as part of a comprehensive LOTO program. This paper introduces NIOSH’s two-phase implementation of an IoT-based intelligent machine monitoring system.

By S. L. Pohlman

Physical characteristics of possible importance in the acid leaching of Chrysocolla have been evaluated. Surface area studies and pore size distribution indicate: 1) a large surface area (350 m /gm); 2) an average pore size of 13 or 16 Å , depending upon use of the adsorption, or desorption, branch of the Type IV isotherm in the evaluation; ) the presence of a significant fraction of pores of size less than 15 Å determined by the accumulation surface area method. The initial structure is micro- crystalline on the basis of x-ray powder patterns; the silica leach residue is amorphous and has only 24 m2 /gm surface area, and loses integrity when dry. However, readsorption of copper onto the wet leach residue gives a product with integrity and 100 m2 /gm surface area. Visual observation of the leach residues supports evidence of a non-protective diffusion mechanism of leaching which is well correlated by the shrinking core model previously presented.

Jan 1, 1976

By A. J. Kraemer

This paper is the second and concluding report of the results of the Bureau of Mines' twenty-second semiannual survey of motor fuel marketed in the United States. The first paper Was published as Report of Investigations 3063 and reported data relating to gravity, vapor pressure and distillation range of the samples. The present paper deals particularly with results of the determination of copper strip corrosion (method 530.22), color (method 10.11), sulphur content by the lamp method, copper dish evaporation residue (method 530.1), and "gum" content as given by the steam-oven method as developed by the Bureau of Mines. The price at the time the sample was taken and the tax are also stated for each sample. The sample numbers used throughout this report are identical with those used in Report of Investigations 3063; for example, No. 225 of this report is the same sample as No. 225 of Report of Investigations 3063. This is the first semiannual motor gasoline survey of the Bureau 6f Mines in which some data were obtained on antiknock values for samples collected in the survey. The Bureau of Mines is not provided with equipment for making these tests in its own laboratories, but composite samples were tested in the laboratories of the Bureau of Standards and the report on these samples is given as a supplement to this paper (pp. 11 to 14).

Jan 1, 1931