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By C. P. Haller, S. J. Aresco

"INTRODUCTION The Bureau of Mines has been active in promoting the purchase of coal for Government use under specifications that define the requirements in terms of heat¬ing value of the coal, expressed in British thermal units, and the composition as shown by proximate analyses. To these, when required, are added the fusing temperature of ash and the free-swelling index. Under most of these specification contracts the bidders guarantee the quality of the coal, and that guaranteed by the successful bidder becomes the standard of his contract. The deliveries are sampled in accordance with instructions./ issued by the Bureau; the samples are analyzed in the Bureau's laboratory to determine whether the coal is of the quality guaranteed by the contractor and, if it is not, a price adjustment is made.Analyses of the delivered coal and ""tipple"" samples (samples collected at mine tipples as coal is being loaded into railroad cars or trucks) provide valuable data for use in evaluating future bids. Moreover, the continuous sampling of coal as delivered is a check on the practical results obtained in burning the coal.The Government purchased approximately 5-1/2 million tons of coal in fiscal year 1951. In connection with these purchases, the Bureau analyzed 10,700 samples. These are published for the use of Government officials and the public. A series of publications s been completed on coal analyses by States, or, where production is small in any State, by groups of adjacent States. In addition to analytical data showing composition and quality of coals of the States, the publications contain brief descriptions of the geological structure of the coal basins, typical mining conditions in the various districts, the principal economic data of the industry, and the relationship of mine or channel samples to delivered and tipple samples. The present publication covers many States but deals only with the analytical data of the coals.The technical papers published by States, with their numbers are: Alabama, 347; Alaska, 682; Arizona, California, Idaho, Nevada, and Oregon, 696; Arkansas, 416; Colorado, 574; Illinois, 641; Indiana, 417; Iowa, 269 and 706; Kansas, 455; Kentucky, 308 and 652; Maryland, 465; Michigan, North Dakota, South Dakota, and Texas, 700; Missouri, 366; Montana, 529; New Mexico, 569; Ohio, 344 (and Bulletin 499); Oklahoma, 411; Pennsylvania Bituminous, 590 (Supplement, 645); Pennsylvania Anthracitic, 659; Tennessee, 356 and 671; Utah, 345; Virginia, 365 and 656; Washington, 491 (Supple¬ment, 618); West Virginia, 405 and 626; and Wyoming, 484."

Feb 1, 1953

By Erin N. Legault-Seguin

The Lac des Iles Mine (LDI) is located approximately 100 km northwest of Thunder Bay, ON. The mine has been in operation since 1993. The initial mine production was 2,300 mtpd and increased to 15,000 mtpd following a mine expansion project that was completed in 2001. Effective Oct. 29, 2008, LDI was shut-down under care and maintenance due to low metal prices. Prior to shutting down, LDI was the only primary PGM deposit in operation in Canada and of the few found globally. The complex geology and physical properties of the deposit causes several challenges for the concentrator. This paper will discuss the solutions to the main challenges of attaining nameplate tonnage and achieve satisfactory Pd recovery and concentrate grades.

May 1, 2009

By B. J. Timmons

Depending upon which of two letters describing the theme of the session I chose to honor, the subject choices because either one or three. They were: "Applied Research and Exploration and Discovery" or "Applied Research in Exploration and Discovery." The final choice; to partially ignore both of them. That minor difference in meaning may be appropriate here, inasmuch as very minor research/exploration differences may also have profound impacts on discovery. To further set the stage, I consider myself an Industrial Minerals geologist, and more specifically primarily associated with basic construction materials crushed stone and sand & gravel. My remarks will apply primarily to those materials. Therefore, when the discussion instructions included emphasis on beneficial aspects (to name a few): "drill target definition; elimination of ore potential; ore forming environments; alteration studies, and isotope analysis," problems became apparent. Evidently, and although this was a form letter, the drafters of that letter had no idea what was involved in research for a construction materials source. My task may be great.

Jan 1, 1995

By Jeon Jeon, Yong-Kun Choi, Chung-In Lee, Yong-Hun Jong, Hag-Soo Kim

In this study, a computer program to design tunnel blasting pattern has been developed. The program consists of two parts; one is for tunnel blasting pattern design and the other is for blasting modeling to estimate the peak particle velocity, the distribution of fragmentation and the excavation damage zone. We modified the design method of tunnel blasting pattern suggested by Langefors because it provided undesirable pattern in blasting practices such as considerably large center cut and too large burden for Vcut as drilling length increased. As a result, the burden and spacing were reduced to practically appropriate amounts. In addition, the correlation between rock mass rate, RMR, and rock constant in blasting, c, was analyzed based on the data collected from twenty three tests of tunnel blasting. It was concluded that the correlation between them was fairly good enough to be applied in cut design. In order to check the validity of the modified methods and their practical applicability, test blasting was carried out at two different tunnel construction sites in Korea. The results were satisfactory in that the average rate of advance was 90% and the overbreak did not cause additional support. Futhermore, the developed program is capable of estimating peak particle velocity by using (a) the existing vibration equations, (b) the vibration equation obtained by test blasting to check out the practical applicability of the designed blasting pattern. Feedback is implemented into the program to adjust the designed blasting pattern and control the vibration.

Jan 1, 2005

By E. Giama, A. Macridis, A. M. Papadopoulos

ISO 14031 is an international standard that describes a process for measuring environmental performance evaluation by setting quantitative indicators and providing a structured approach for organizations to follow, independent of location, size, complexity and type of activity. It is not a standard for certification as ISO 14001 is, but it fits into the ISO 14000 series of standards and is intended to assist organizations to apply environmental management systems and obtain environmental evaluation. This case study’s main objective is to identify the interaction between ISO 14031 and ISO 14040-42. ISO 14040-42 is referring to Life Cycle Analysis (LCA) methodology. More specific, LCA is applied (based on the ISO 14040-42 standard) to stone wool’s production, the market dominating thermal insulation material, produced by bauxite and amphibolite. LCA is used as a decision making tool for the development of environmental indicators (based on ISO 14031 guidelines) and for environmental performance evaluation.

Jan 1, 2005

By J. Darlington, A. K. SenGupta

Water-swellable layered silicates, namely, the smectite clays can remove suspended materials (called herein as debris) and metal ions from aqueous streams. The present study shows that the flocculating and metal extracting abilities of smectite clay-based flocculants can be enhanced when these clays are used in conjunction with a specific anionic polymer. Such performance enhancement is attributed to the following: i) the clay-dispersing ability of the polymeric additive, that would translate into an increase in the clay-surface area available for the attachment of the debris particles onto the clay particles; ii) the possibility of dispersant-to-coagulant transition of the polymer during the later instants of the treatment process, as a result of reduction in solvency of the wastewater for the polymer due to the release of cationic species from the clay-based flocculant solids; iii) metal-complexing ability and adsorption properties of the polymer.

Jan 1, 2002

By Daniel H. Isreal

Because the federal government owns and controls nearly 80% of the most valuable oil shale reserves in the West, it is inevitable that federal leasing and siting will play a prominent role in development of an oil shale industry during the 1980s. Also, because of recent enactment of the Synthetic Fuels Corp. authorizing up to $88 billion in loan and price guarantees-federal financing will provide the critical incentive to permit private investment in a still infant industry.

Jan 1, 1981

By E. Contestabile, R. von Rosen, R. Guilbeault, R. Fouchard, P. Lightfoot

In August 1998, a truck loaded with 18 tons of blasting explosives, including over 13 tons of ANFO, left the road near Walden, Ontario. The crash caused a fire; approximately 30 minutes later a large detonation occurred, causing substantial damage to the roadway and local property. Although nobody was injured in the explosion, the consequences of a similar incident in a heavily populated area could have been catastrophic. Following the Walden incident, Transport Canada and Natural Resources Canada embarked on an extensive experimental program to determine the cause of the detonation. This paper describes part of that experimental program, designed to understand better the thermal decomposition of ANFO.

Jan 1, 2003

By F. F. Roberto

Many techniques that are used to characterize and monitor microbial populations associated with sulfide mineral bioleaching require the cultivation of the organisms on solid or liquid media. Chemolithotrophic species, such as Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, or thermophilic chemolithotrophs, such as Acidianus brierleyi and Sulfolobus solfataricus can grow quite slowly, requiring weeks to complete efforts to identify and quantify these microbes associated with bioleach samples. Real-time PCR (polymerase chain reaction) assays in which DNA targets are amplified in the presence of fluorescent oligonucleotide primers, allowing the monitoring and quantification of the amplification reactions as they progress, provide a means of rapidly detecting the presence of microbial species of interest, and their relative abundance in a sample. This presentation will describe the design and use of such assays to monitor acidophilic microbes in the environment and in bioleaching operations. These assays provide results within 2-3 hours, and can detect less than 100 individual microbial cells.

Jan 1, 2009

By F. Z. Utyashev

The present work considers the essence of fragmentation: on the level of a simple model as a material response to the curvature accumulated by it at large deformations. It is on this basis that the correlation between curvature and fragment sizes is determined. It is shown that at deformation the area of curvature center inevitably changes. It is revealed that a specific value of variation of center surface area, i.e. ^As parameter, is numerically equal to the value of curvature acquired by a material. Minimum sizes of fragments and grains depending on ^As have been estimated, and the dependence of this parameter on strain has been established. Besides, the present paper considers the effects exerted by curvature center geometry, material distortion, directions of deformation and thermal warming up in the localization zones on structure refinement when various techniques are applied.

Jan 1, 2006

By Peter N. Holtham, Mary M. Ng

"Resistivity measurements of minerals in the laboratory are commonly made with a low DC voltage source. Common test voltages specified in the ASTM Standard D257 are 100, 250, 500, 1000, 2500, 5000, 10000 and 15000 V, however 100 and 500 V are the most frequently used. Resistivity results obtained in the laboratory have been used to infer the electrical behaviour of minerals undergoing electrostatic separation. However because the voltages employed in electrostatic separation in the plant are of the order of thousands of volts, typically greater than 15000 V, whether the laboratory results are applicable as a predictor of plant performance is a critical question. It is unclear whether resistivity values taken at a low voltage are characteristic of those seen in electrostatic separation, in which the minerals are exposed to a much higher voltage. No definitive answer could be found in the literature.In this work, the resistivities of zircon, rutile and ilmenite were measured in a corona field for the first time. The measurement principle was based on a technique developed to measure fly ash resistivity in electrostatic precipitators, however the test apparatus and findings are novel.Resistivities of rutile and zircon were found to be easy to measure. The values measured in a corona field were several orders of magnitude less than those obtained with a dc voltage of 100 V. Evidence of back corona was observed with zircon. When the voltage drop was greater than the sample layer could withstand a localised electrical stress developed, resulting in a voltage breakdown, at which point a sudden surge of corona current (back corona) was detected in the sample layer. Rutile, on the other hand, exposed to the same conditions as that of zircon (i.e. same temperature and applied voltage) did not exhibit any sign of back corona. Its resistivity across the range of test voltages (14 to 33 kV) remained fairly constant."

Jan 1, 2003

By Thomas C. Shapiro

This is the second in a series of articles on microcomputers and applications in the minerals industry. The first article (ME, Feb., page 129) discussed microcomputer terms and concepts. This article will discuss software for geology and mining. The third article will cover plant, administrative, and geotechnical software applications. Introduction Geology and exploration are areas where computers have a natural fit. Large volumes of data need to be tabulated, evaluated, and made into maps and reports that allow geologists and management to make a decision on a project or mine. Until recently, the programs that performed these tasks were cumbersome and not user friendly by any stretch of the imagination. Learning time to become an expert in these programs typically would be six months or more. The computers needed to run these programs are expensive mainframes. Several years ago, the use of minicomputers became popular because of their lower cost. Programs were adapted to fit these smaller machines and became friendlier. With the advent of micros, many programs. were rewritten and used the screen capability more effectively, thus providing a real advance in user interface. Programs and Price The definition of micro, mini, and mainframe is becoming blurred. For the purposes of this article, micro refers to either an eight- or 16-bit computer, costing less than $10,000 and, more typically, under $5,000. Mini refers to a 16- or 32-bit computer that typically costs more than $25,000. Mainframe refers to a 32-bit or larger computer that costs more than $250,000. There is a large gray area between micros and minis, and minis and mainframes. Technology and prices are changing so fast that the traditional definitions have become almost meaningless and price has become a better guide. With the arrival of the minicomputer, costs for hardware began to fall, but the programs have tended to remain unfriendly. In some cases, the minicomputer acted as a front end to the mainframe. Cost of both the programs and minicomputers could easily run a minimum of $70,000. A total cost of $200,000 would not have been out of line. The average geologist and company would have a great deal of difficulty justifying such a purchase. The advent of the microcomputer has changed all that. For $3,500 to $5,000, one can buy a 16-bit micro and a printer. Plotters with six pens are available for $2,000 that will produce a 280- x 430-mm (11- x17-in.) map. For several hundred dollars, software is available to act as a word processor, an economic spread sheet, or to perform ground water calculations. In fact, some programs are available for free. Some of these programs are relatively easy to learn. In addition, programs are being developed daily that are easy to use. More importantly, large programs that once ran only on mainframes are being converted

Jan 3, 1984

By Randy Wheeler

The importance of having full wave form information for recorded blast events cannot be overstated. Knowing the peak particle velocity and the frequency at the peak are the tip of the iceberg. This presentation will focus primarily on using the FFT (fast Fourier transform) for detailed frequency analysis. Employing linear superposition to evaluate timing effects on amplitude and frequency will be discussed.

Jan 1, 2005

By J. Flemming, R. O. Burt

"The Tanco pegmatite is located in the Bird River greenstone belt of southeastern Manitoba approximately 160 km northeast of Winnipeg (Figure 1). This pegmatite body was discovered in 1929 and subsequently attempts were made to exploit it for tin by Jack Nutt Mines Ltd. and later in the middle 1950's by Montgary Oil Ltd., who extensively developed but did not produce from, its lithium deposits. In 1966 systematic investigation of the pegmatite as a potential source of tantalum led to the founding of Tantalum Mining Corporation of Canada Ltd. (TANGO) in 1967 and production of tantalum concentrates from the Bernie Lake mine commenced in 1969. Tanco is currently jointly owned by Hudson Bay Mining and Smelting Co., Cabot Beryl co Inc. of Boston, and the Province of Manitoba. (Williams and others 1978, Burt 1979, Burt and others 1982), continued until the end of 1982, when, due to falling demand and prices, operations were suspended.During the 1970's Tanco had investigated the potential of the lithium orebody; carrying our research into both the concentration of the ore and into the production of lithium chemicals. However lithium chemicals were in an over-supply situation, due in part to the production from Chilean brine deposits (Buckley, 1983), and Tanco' s own plans were put into abeyance. The potential alternative market, the direct use of concentrates in the glass and ceramics industry, did not at the time justify the cost of constructing a new plant."

Jan 1, 1986

By V. F. Parry, W. S. Landers, John B. Goodman

"INTRODUCTION The object of this investigation was to demonstrate a satisfactory method of storing slack subbituminous coal in open pits in a manner,that would minimize the cause of the physical deterioration and would have a practical application.The storage of coal by industrial plants is to their advantage, since an adequate operating supplying of fuel is available at all times as insurance against transportation delays, shortages, and strikes. Furthermore, it is possible to participate in low seasonal freight rates and mine costs by permitting the railroads to utilize idle equipment and by taking advantage of the off-peak production at the mines. For a number of years, one of the larger beet-sugar companies operating in the Rocky Mountain region has taken advantage of the lower prices and seasonal production of subbituminous slack coal during the summer months and purchased a large proportion of its requirements for the annual winter campaign. This company, operating sugar-refining plants in the 1943 campaign, used 256,613 tons of subbituminous coal. Of this quantity, 166,636 tons was purchased during the off-peak season and stored for use during the winter. It is the practice of this concern to place coal purchased through the months of January to October in underwater storage for use in the beet-sugar campaign, which lasts from October to as late as, January. The beet-sugar refining ""campaign"" period starts immediately after the beginning of the beet harvest and lasts 60 to 70 days."

Aug 1, 1946

By Anthony Iannacchione, Christopher Mark

Residents of Maxwell Hill, a suburb of Beckley, West Virginia, reported from January until March of 1988 a series of earth tremors. The tremors rattled dishes, and the noises associated with tremors were sometimes loud enough to wake people at night. These events were puzzling because Beckley is in an area of low seismic activity. Maxwell Hill is located above abandoned coal mines, though no direct subsidence damage to surface structures has been documented. A research program was initiated to determine whether subsurface ground movements associated with the abandoned mines could be responsible for the seismic activity experienced at the surface. A hypothesis is proposed which states that seismic disturbances can be caused by abandoned mine failure when two conditions are met. First, some instability must exist at the mine level. The most likely cause of instability is the failure of pillars of coal that were left for support at the time of mining. Second, subsurface movements can result in significant seismic activity only when the rock above the mine contains at least one very strong and brittle layer that is prone to fail violently through rupture or fault slip movement. Analysis of the data indicates that both hypothesized conditions for mine-related seismicity appear to have been satisfied in the case of Maxwell Hill. It has therefore been concluded that the earth tremors experienced by Maxwell Hill residents probably are related to the abandoned mines. Analysis of the potential magnitude of these events indicates that they are unlikely to cause significant surface danlage. The probability that future events will disturb the residence of Maxwell Hill should be quite low based on the identified mechanism.

By J. A. Finch, J. Vergouw

"Flotation selectivity becomes progressively more difficult to achieve with decreasing particle size. One of the possible problems is agglomeration, i.e. particles clustering together. One mechanism derives from the surface charge all particles develop in water. Agglomeration driven by surface charge is known as coagulation. One form is coagulation between particles of two different minerals of opposite charge. Another is coagulation between particles of the same mineral when conditions are such that the charge approaches zero.The paper describes the method of measuring charge and a new automated settling technique for measuring agglomeration. The phenomena are illustrated with galena and pyrite. Methods of assessing the importance of agglomeration in the plant environment are still to be developed.IntroductionFine particles can agglomerate (i.e. adhere to each other) under certain conditions. This is counter-productive for any physical separation process, including flotation. One cause of agglomeration derives from the surface charge that all particles develop in water. Agglomeration due to surface charge effects is referred to as coagulation. There are two forms of coagulation. If the surface charge is brought to near zero then the force of repulsion is lost and particles coagulate. This usually applies to particles of one mineral type and the technical tenn is homocoagulation. On the other hand, if two particles have opposite charge there is an attractive force. Since the particles in this case are usually different minerals this is known as heterocoagulation.Both types of coagulation can cause minerals to be misplaced. In the case of heterocoagulation this is fairly obvious. One example that may be familiar is slime coating (fines of one mineral coating larger particles of another) But even homocoagulation can be a problem an agglomerate of the same mineral particles can entrap particles of another mineral."

Jan 1, 1997

By Hamid-Reza Manouchehri

"The triboelectric charge attributes of some silicate minerals (i.e., feldspar, quartz and wollastonite) after contacting different triboecharging medium made of different materials were studied. The charge acquisitions by different size fractions of minerals were monitored and accordingly the energetic work function values, i.e., the main parameter determining the entity of triboelectric charges acquired by mineral grains, of the examined minerals were estimated. Moreover the separation behavior of different size fractions of these minerals through the electric field of a laboratory free-falling separator when the mineral grains are charged by different tribochargers were observed and considered as the electrical separation potential of the examined minerals.Furthermore, the role of adsorption of different chemical species on triboelectric charge characteristics and charge acquisition of mineral samples were described from theoretical point of view and the effects of some chemical reagents on triboelectric charge acquisition of the examined minerals were studied. In addition the separation behavior of chemically conditioned quartz, feldspar and wollastonite minerals, using different anionic and cationic reagents, through the electric field of a free-fall electrostatic separator before and after chemical conditioning were monitored.Finally an attempt was made to translate the findings from single mineral systems to a complex silicate ore, containing mainly of feldspars, quartz, and wollastonite. Different separation tests under various conditions were conducted to this complex silicate ore. Before passing through the separation device, the ore sample was conditioned by different cationic and anionic reagents and then was triboelectricaly charged by different tribocharging medium in order to find the effective reagent and tribocharging medium for separating silicates. Besides the role of temperature and humidity of the surrounding ambient in separation behavior were considered."

Jan 1, 2003

By Carlos Frias

The lead-acid battery recycling is a major industrial activity (more than four million tonnes recycled lead per year) that generates large amounts of toxic wastes such as lead slag, mattes and acidic sludge, besides airborne emissions. This is a waste-producer industry that needs a definitive solution to avoid its negative environmental impact and getting a sustainable lead production. That is the principal target of the CLEANLEAD technology, which properly combines both hydrometallurgical and pyrometallurgical routes aiming to get zero-waste production, reducing the use of energy and resources in all phases of battery reprocessing, and consequently, greatly decreasing the operating cost. There will be no toxic emissions to land, water or air, and obtained products are pure lead metal or pure lead oxide, and commercial gypsum instead of waste sludge.

Jan 1, 2006

By Peter Bourke, Marc van Olst, Seppo Ronkainen, Natalie Brown

"Since the early days of flotation, process technicians have known that the speed at which the froth is recovered over the lip of the cell has a very direct and consistent influence on the grade and recovery of the circuit. No plant would deny that, even to this day, one of the most important aspects of a process technician’s job is ensuring that the froth is moving at a desired and controlled speed over the lip. Unfortunately, process technicians cannot watch the froth throughout the entire shift, as there are always a lot of other tasks to do.A considerable amount of work has thus been done to develop a “system” that automatically measures the speed of the froth. This measurement would then be used in simple controllers to emulate the steps taken by the process technician in correcting deviations of the froth speed from its desired level. Many of the earlier attempts to measure speed were ineffective, as they were unable to cope with turbulence on the froth surface. The FrothMasterTM instrument makes use of machine vision technologies to measure the speed of the froth over the lip of a cell at a very high sampling rate. This instrument produces an extremely reliable and accurate measurement of the froth speed (as well as other parameters such as bubble size and froth stability). As we will show, the effectiveness of the speed measurement in controlling the performance of the plant is a testimony to its reliability.Three FrothMasterTM units have recently been installed on the Cadia Hills Gold Mine in New South Wales (Australia). The objectives of this installation were:To control the mass-recovery of two Tank Cells in series on the same level where differences in the hydrostatic head between the two cells result in the cells pulling inconsistently with respect to each other.Control of the concentrate grade (%Copper) from the first rougher.Reduction in the frother consumption in the rougher circuit by monitoring the froth speed.A simple controller was designed to react to disturbances in the same way that human operators react. This was done after consultation with the metallurgists and the process technicians at Cadia. The controller had two functions:Stabilisation: The stabilising controller made use of three manipulated variables (level, frother addition rate and aeration rate) to control the froth speed to a setpoint.Optimisation: The optimising controller adjusted the froth speed setpoint based on deviations of the grade (measured in real-time with an OSA) from a setpoint. The plant metallurgist adjusted the grade setpoint based on information about the ore."

Jan 1, 2001