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By N. W. Stump

New developments in on-stream analysis using immersed radioisotope gauges including results from plant installations are described. The control of grinding and flotation using a small digital computer has been complemented by this development. A control scheme for grinding which is based on maximum throughput at constant product size and preliminary work in flotation control are also outlined.

Jan 1, 1974

Ferric (Fe3+) ions are omnipresent in flotation circuits. Depending on pH and the nature of the ore body, Fe3+ ions may play a role in the adsorption of thiol collectors on sulfide minerals. To investigate this possibility, a two-compartment galvanic coupling cell was designed. This cell was used to monitor changes in contact angle of a sulfide mineral in one compartment, while varying concentrations of the Fe3+ ions in the other. The results showed that Fe3+ ions promote xanthate adsorption as indicated by the increase in contact angle. Implications of this finding in sulfide mineral flotation in general will be discussed.

Jan 1, 1998

By A. L. Mular

In order to simulate a grinding circuit, it is necessary to obtain valid mathematical models of the grinding mills and classifiers in the circuit. Several models of grinding mills Ova been proposed 1,2,3 and models of cyclone classifiers are available 4,5. Those models developed by Lynch et. al. 3,5 have been tested in the plant, so that some degree of reliability can be placed on them. Because of this, it is reasonable to assume that the Lynch models will apply for a given circuit, and then to test this assumption. Empirical modifications are made as necessary for a given situation. Usually, valid simulation models can be modified slightly to provide control models6,7. The purpose of this paper is to describe the results of an approach taken by Mular8 to obtain the Lynch models of parallel cyclone classifiers being used in the A-circuit of the new Strathcona Mill***.This was one of the projects undertaken by the fourth year Metallurgical Engineering Class of 1969, Queen's University, Kingston, Ontario, Canada, as part of their process design course which cooperates closely with the Canadian metallurgical industry.

Jan 1, 1970

By A. A. Campoli

A stress control design strategy was developed to minimize the explosive failure of highly stressed pillars, during room-and-pillar retreat mining conducted between stiff immediate roof-and-floor strata. A confined core coal pillar strength model was based on in-mine geotechnical evaluations of successful room-and-pillar and longwall bump control designs. Tributary area and linear shear angle approaches were used to estimate development and gob side abutment pillar loads for supercritical section widths. Subcritical width sections separated by barrier pillars to control stress within total extraction panels were optimized with the boundary element program MULSIM/NL.

Jan 1, 1994

The Kinross DeLamar Mine has been operated for more than 17 years producing precious metals dore' from ores, principally silver bearing with associated gold co-products. In late 1995 a new orebody was commissioned, the Stone Cabin orebody, and the site began a phased shift from silver dominance to gold dominance in terms of precious metals revenue. The Knelson Concentrator was selected to remove gold from a portion of the cyclone underflow stream in the grinding circuit. This paper describes the development of the flow sheet, specific mineralogical impacts on Knelson product and downstream materials, and impacts on mine/mill grade reconciliation.

Jan 1, 1997

By J. A. Halt, E. Larsen

"The Sydvaranger magnetite mine closed in 1996 due to low iron ore prices and was reopened in 2009. The flowsheet has remained more or less as in the old plant, based upon two grinding steps followed by magnetic separation. The magnetite is free of harmful elements and should be attractive on the high quality market. This requires a concentrate containing less than 2% SiO2, which previously was achieved by amine flotation. Amine was preferred because it could be used with sea water. The use of amine is now restricted by the Norwegian Climate and Pollution Agency. Therefore, testwork to replace cationic with anionic flotation was done. Activation of quartz with Ca or Mg ions prior to anionic flotation was shown by research from 1960 to 1980 to be effective under laboratory conditions. The old research results have been followed up in order to make a commercial process for Sydvaranger. Calcium activation works excellently with all Sydvaranger ores, including the ones containing amphibole minerals, but Ca activation requires the high and not environmentally friendly pH of 12.4. Magnesium activation at pH 10.5 is a little more challenging, because the maximum concentration of MgOH+ is about 100 times lower than that of CaOH+. Fortunately, the major impurity in the main Bjornevatn orebody is quartz, which responds well to Mg activation. The process does not appear to depend much upon water quality, as the silicates may already be activated during grinding and magnetic separation in recycled water. The new process is environmentally friendly, as only well-known household reagents are used; oleic acid or tall oil, dextrin, sodium hydroxide and magnesium chloride at pH 10.5.IntroductionThe processing plant of Sydvaranger Gruve AS (SVG) is located in the port town of Kirkenes in the northernmost part of Norway, 10 km by rail from the high-grade deposit of Bjornevatn. This plant has been able to beneficiate magnetite ore to up to 99.5% purity, as described by Sandvik and Malvik (2001). Using the magnetic properties of the ore and making the most out of its enviable liberation characteristics, the original plant consisted of ball mills and 600-mm magnetic separators. The plant was shut down due to market conditions in 1996 but reopened in 2009."

Jan 1, 2015

By M. U. Khan, A. D. S. Gillies

"Diesel exhaust is a major cause of large number of occupational diseases. Acute and continuous exposure to Diesel Particulate Matter (DPM) can cause numerous health issues including respiratory disease, reduced lung capacity, heart disease etc. The National Institute of Occupational Safety and Health (NIOSH) and the International Agency for Research on Cancer (IARC) consider diesel engine exhaust as carcinogenic. In large underground metal and nonmetal mining operations, regulatory compliance regarding miner’s exposure to airborne particles especially DPM is a big challenge. Complex mine networks add more difficulties in controlling DPM. MSHA relies on the NIOSH 5040 method for DPM compliance. The NIOSH 5040 method is a shift average based method which inherits some limitations. Due to these inherent limitations of the NIOSH 5040 method the concept of real-time DPM monitoring is promoted in the mining industry. Several real-time DPM monitors have been used by the researchers and efforts still continues to improve their measuring techniques and understanding. Real-time monitoring of DPM is vital to gain understanding of rapid changes in the mine atmosphere. The current study highlights the advancement in real-time DPM monitoring and mainly covers a review of several studies in which DPM concentrations were measured by utilizing real-time DPM monitors. INTRODUCTION Ventilation of underground mines is an important aspect of mining operations. Mining is a continuous activity and the ventilation networks in modern mines change with extended developments. Proper understanding of the ventilation network is a key design factor of an optimum mine ventilation plan. An important task of underground mine ventilation engineers is to provide clean air with sufficient quantity to the underground miners (Khan M. U. and Gillies A.D.S. 2015). The amount of fresh air supplied to the mine should be adequate to dilute the concentrations of contaminants present in the mine atmosphere. In the United States it is estimated that diesel powered equipment is used in thousands of mining operations (Stephenson D. J. et al. 2006). Use of diesel powered equipment is an attractive option in underground mines due to its several advantages over other available alternates. Diesel engines are rugged, dependable and fuel efficient (McKinnon 1999). It is common for diesel engines in heavy duty trucks to have a life of 1.6 million kilometers (McKinnon 1999). Looking at the developments in other energy alternatives, it can be assumed that the underground mining industry will maintain its reliance on diesel powered equipment (Anon 2001). DPM is an important source of mine air contamination in many non-gassy underground mines (Khan M. U. and Gillies A.D.S. 2015). Diesel exhaust is harmful for humans. Acute and continuous exposure to diesel exhaust concentrations can cause several health issues. Some of the health diseases caused by DPM exposure are respiratory diseases, reduced lung capacity, heart disease, and lung cancer (National Research Council. 1981, Mine Safety. 2005). In addition, NIOSH regards diesel exhaust as “potential carcinogen” (Centers for Disease Control 1988) and IARC has declared that “diesel engine exhaust is carcinogenic to humans” (IARC 2012). NIOSH has also declared that the reductions in DPM exposure would reduce cancer risks (Centers for Disease Control 1988)."

Jan 1, 2016

By A. J. Kwitowski

Remote control for mining machines ordinarily means the operator is not seated on the machine, but is located within direct view of the machine and work area Thus, remote control operators are exposed to the hazards of roof/rib falls and dust/methane explosions. The U.S. Bureau of Mines has developed a method to disassociate remote operators from these hazards. Off-board, computer-based "tele-operational" systems are utilized that station the operators one-hundred meters or more distant from the working faces. Details are provided for tele-operated systems for thin-seam extraction and haulage equipment in highwall and deep, room-and-pillar coal mines.

Jan 1, 1992

By G. L. Brooke

At present, there are two known cobalt deposits in the 48 contiguous states. This paper is a brief description of one of these deposits. It is a Mississippi Valley type deposit, but somewhat atypical in that the metal of greater interest is cobalt as opposed to lead, zinc, and copper. The history and present work are outlined along with a discussion of the geology and mineralogy.

Jan 1, 1981

By N. S. Tanious

This work was completed prior to the author's appointment with the Nuclear Regulatory Commission (NRC). Therefore the views and conclusions contained in this paper are those of the author and should not be interpreted as necessarily representing the official policies or recommendations of the NRC. Reference to specific brands, instruments, or trade names is made to facilitate understanding and does not imply endorsement by the author or the NRC.

Jan 1, 1987

By Billy W. Parks

This paper reports on the first 2 years in operation of a special-purpose coal handling rig which provides blending, temperature reduction, and continuous, automatic mechanical sampling as part of midstream barge to ship coal transfers. Briefly reviewing some of the characteristics of coal handling peculiar to midstream transfers, the paper discusses how the most beneficial aspects of midstreaming were enhanced through the design of this blending and sampling rig.

Jan 1, 1986

By E. O. Strahl

In the search for economic mineral deposits, the need for efficient mineral or chemical assays is of prime importance. Costly analytical methods and long delays in obtaining assay results severely limit the effectiveness of an exploration program. The assay problem becomes acute once a potential ore body is located and large numbers of samples are generated in close interval drilling programs. In order to avoid the delays and high costs of extensive assays, the exploration geologist or mining engineer is likely to be required to curtail his drilling program, composite samples, or restrict the required analyses to a limited number of critical elements. As a result, the definition of the potential ore body may be less than needed for final economic evaluation. The assay requirements for bauxite exploration usually involve a considerable number of total elemental and empirical analysis. Since the Bayer process for extracting alumina from bauxite involves the selective dissolution and reaction of specific minerals from the bauxite, a direct chemical analysis for elemental composition yields only a portion of the data required to effectively describe the potential economic value of ore body or deposit. To fully characterize the economic value of a bauxite requires digestion, mud separation and mud settling tests under conditions approximating a commercial Bayer plant. A close approximation of the process behavior of a bauxite also can be calculated from a combination of the chemical and mineralogical analyses. By determining the elemental chemistry, mineralogy, and Bayer plant processing characteristics of a few samples of a given bauxite, correlations can be derived that permit defining a bauxite in terms of a given set of process conditions.

Jan 1, 1977

By Allan R. Ide

It is a great pleasure for me to speak-before such a prestigious group as the American Institute of Mining, Metallurgical and Petroleum Engineers. The substance of my talk today is the handling of coal and petroleum coke: their characteristics and environmental problems, and how we were able to correct the problems, prescribe the cure and enjoy the benefits. When coke first became a by-product derived from the oil refineries everyone would have been very happy if someone had offered to take this pro- duct off their hands. Unfortunately, there was no market at that time, and no one seemed interested. Soon thereafter, it became a sellable product and began to be shipped to many countries in the world. This was when all of the pollution problems began. I will be talking briefly about some of these problems and showing a short film on this subject afterwards.

Jan 1, 1984

By P. Zhang, W. D. Xiao

"A process mineralogy study was conducted to guide the development of a process for the extraction of vanadic oxide (V2O5) and aluminum compounds from bone coal and its ash as well as the production of byproducts. Results show that to extract the targeted metals at higher recovery rates, one must find a suitable agent capable of destroying the structure of the mica and breaking down the lattices in which these metal-bearing minerals occur. For such minerals, metal extraction efficiency is usually low if the approach is simply adding an oxidant that cannot destroy the structure. In this research, a byproduct fluosilicic acid (H2SiF6) at 20 percent concentration from an operating phosphate fertilizer plant was found to be powerful and effective for the leaching of vanadium-bearing minerals such as mica. This environmentally friendly process improved the leachability of valuable constituents in the bone coal significantly, with the leaching rate of V2O5 increased to 94 percent, from 83 percent, and that of aluminum oxide (Al2O3) increased to 75 percent, from 40 percent. X-ray diffraction and chemical analyses showed that the structure of mica can be destroyed using fluosilicic acid either alone or in combination with sulfuric acid. Based on the process mineralogy study, a processing flowsheet was tested, which resulted in a final V2O5 powder product with purity of 99.2 percent and an overall recovery rate of higher than 85 percent. The flowsheet consists of leaching, ion exchange and ammonium precipitation. With this process, various byproducts could also be generated, including aluminum fluoride, cryolite, aluminum sulfate, calcium sulfate, ammonium chloride, sodium chloride and cement admixtures.IntroductionVanadium is an important rare metal broadly used in the production of steel alloys and nonferrous alloys as well as in the chemical field as a catalyst. Vanadium-bearing bone coal and clays are abundant in China, and they contain other valuable metals such as aluminum. Bone coal is a type of carbonaceous shale. The vanadium-bearing minerals mainly exist in mica, kaolin, iron oxides, tourmaline and garnet. According to previous studies (Xiao, 2007; Xu, 1989; Xu and Chen, 1991; Ji and Xu, 1991; Chen and Xu, 1992; Xu and Heng, 1992), vanadium occurs from the isomorphous substitution of V3+ for Al3+ or Fe3 + in the crystal lattices of mica, tourmaline, garnet, dolomite and aluminosilicate minerals. In iron oxide and kaolin minerals, vanadium appears as an adsorption form. The isomorphous substitution of vanadium is more stable in tourmaline, garnet and silicate minerals. Therefore, vanadium in bone coal may exist in three phases: vanadium-containing kaolin and oxides, vanadium-containing mica, and tourmaline and garnet (Xu and Chen, 1993; Xu and Zhang, 1993; Xu and Wang, 1994; Feng, et al., 2005; Lin and Fan, 2001)."

Jan 1, 2015

By Charles E. Michener

This paper deals with the occurrence of basic and ultrabasic rocks and their relationship in space and time to major structures of the earth. In order to introduce the paper properly, I must go back a little and try to put the subject in perspective. In the brief time that geology has been a scientific occupation, ore deposits have been grouped and classified in various ways depending on the theories that happened to be popular at the time. Some of the early scientists said that ore came from fire, other schools argued that ore originated from water. Then came the lateral secretionists and in later years the hydrothermalists led by the Lindgren school and the latter has largely been accepted as the modern concept of ore deposits. It now seems apparent that the hydrothermal school is being seriously challenged by other schools of thought. It also seems that we have reached the point where we should be willing to admit that we do not really know in most cases how the ore got to its present position. However, for practical purposes, we can classify ore deposits as to the environment in which they do occur. This is not difficult and gives the field geologist and the mining engineer something to work with and to believe in, and it gives them a basis for carrying out their field work. On the screen, Figure 1, there is a classification of ore deposits based on the environment. Under each classification is listed the more prominent metals which are characteristic of that

Jan 1, 1971

By K. P. Chong

Fracture toughness of oil shale is an essential property in fragmentation to optimize particle sizes and permeability distributions in in-situ processes. Fracture mechanics of oil shale has been based on conventional fracture mechanics using notched samples and assuming the material to be isotropic and elastic. Oil shale is a layered material more accurately characterized as transversely isotropic. The senior author proposes to use a semi- circular core specimen with a center crack subjected to three point bending. Singular crack tip elements with isoparametric elements are used. The precracked semi-circular disk is modeled under displacement loading. The effect of crack length on the non-dimensionalized stress intensity factor is investigated by strain energy method, ellipse method, and stress method. Very close agreements are found. The fracture toughness is obtained by compressing the specimen in to failure. Parameters such as oil yield are investigated.

Jan 1, 1984

By B. J. Timmons

An initial point that I would like to make very emphatically?and as our title might erroneously suggest for those of you old enough to remember . . . Peter Harben and myself do not intend to shoot ourselves in the foot. We derive our livelihood from a number of aggregate, industrial and other minerals producers, both here in the United States and outside. This paper, therefore, is a fence-straddler or for information purposes (we hope) only, rather than any "fur or agin" stances. In essence, some of you may consider it a U.S.G.S. publication! In fact, we hope that it serves to inspire aggregates producers to do some radical thinking, to promote introspection, and to that end it would benefit both domestic and foreign producers. The title could be shortened into a brief question of "Aggregates Travel?" with an emphatic no for the answer. In the past, the success of a construction materials venture depended upon your ability, through siting, to provide the customer f.o.b. the job site, a product at the lowest possible cost.

Jan 1, 1987

By Y. C. Guan

The leaching kinetics of chalcopyrite in ammonium iodide solutions with iodine has been studied using rotating disc. The variables studied J include the concentrations of lixiviants, rotation speed, pH of the solution, reaction temperature, and reaction product layer. The leaching rate was found to be independent with the disc rotating speed. The apparent activation energy was measured to be about 50 kJ/mole from 15°C to 35°C, and 30.3 kJ/mole from 35°C to 60°C. Experimental findings were described by a kinetic model, and the overall rate was found to be: (formula)

Jan 1, 1997

By Harold L. Lovell

Problems associated with fines (minus 6 mm, 1/4-inch) production, preparation, and utilization have long plagued the coal industry and are now more acute than ever. Continuous deep mining systems create more fines which have moisture; content greater than natural levels from dust control spraying and often add substantial levels of mineral matter due to mining selectivity constraints. Frequently, during preparation, more -fines are developed to achieve improved component liberation. Coal consumers often specify small sizes whether for carbonization, combustion, or conversion. Wet beneficiation systems process fines by several' types of unit operations, but usually must also incorporate costly and complex dewatering systems to reduce the moisture content of the products. Existing pneumatic preparation systems are constrained between product equality and yield by the sharpness of separation. These limitations become more severe with decreasing particle size and increasing feed moisture content. Control of particulate emissions, both process and fugitive, during pneumatic preparation, can be forbidding. A pneumatic preparation-process which would overcome these constraints, could be most enticing. The DryFlo system is being evaluated to quantify performance characteristics as regards these constraints.

Jan 1, 1976

By D. R. Nagaraj

Adsorption of sulfide collectors such as xanthate on pyrite has been studied extensively over several decades using a wide variety of techniques. In spite of this, there are unanswered questions as to the identity of adsorbed species on pyrite surfaces -dixanthogen vs. iron xanthate complexes. Far less is known in non-xanthate collector systems. We have used Secondary Ion Mass Spectroscopy (SIMS) successfully in the past to obtain direct evidence for the identity of the adsorbed collector species on copper sulfides, galena and Cu-activated quartz. The present study is an extension of the SIMS analysis to investigate the adsorption of xanthate, dithiovhosphate, dithiocarbamate, and modified thionocarbamates and thioureas on pyrite. Adsorption of these collectors on chalcocite was also studied for comparison. An attempt was also made to obtain SIMS spectra for pure dixanthogens at room temperature. Only in the case of dithiocarbamate (DTC) was there direct evidence for the presence of not only the collector dimer, but also iron-DTC complexes. On chalcocite, only the copper-DTC complexes were detected (no dimer). In the case of xanthate, the collector molecular ion and its S adduct -which are possible fragments from dixanthogen -were detected on pyrite, along with a fragment peak: suggesting Fe2X. For dithiophosphate, the collector molecular ion and Fe(DTP)(OH) complex were detected (no dimer). For modified thionocarbamate and thiourea, adsorption on pyrite was negligible.

Jan 1, 1997