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By Viacheslav Lyakhov, Cornelis H. Iestra, Victor I. Beloborodov, Vitaliy Bogdanovich

The results of a study and effective use of flotation for processing of ores with complex mineral composition containing fine-disseminated minerals with high specific density are presented in the paper. The object of research was complex baddeleyite-containing ore from Kovdor deposit (The Kola peninsula, Russia). Baddeleyite is a valuable, rare mineral, natural Zirconium dioxide with 5.8 - 6.0g / cm density, grade content 0.15 - 0.17 and dissemination less than 0.2 mm. The authors carried out a thorough investigation of baddeleyite- containing products selected in different sites of gravity flowsheet. It was determined that due to similar specific weight some sulphide minerals (pyrite, pyrrhotite) come into concentrate together with baddeleyite and, also, minerals of pyrochlores group (hatchettolite). The results obtained revealed the possibility of use the flotation for retreating rough baddeleyite concentrate. he given gravity concentrate has a number of specific features, e. g. high density of its minerals which, in its turn, provides for high speed of sedimentation of solid phase in pulp, and for the presence of large amount of sulphide minerals (up to 10%) having good flotability. With these features being taken into account a technology for flotation of baddeleyite-containing products after their preliminary gravity concentration has been developed (up to 5 - 10% Zirconium dioxide). The technology has three flotation stages. At the first one the reverse flotation of baddeleyite is carried out during which "light" minerals (forsterite. apatite and carbonites) come into froth product and at the second one flotation of sulphide minerals and at the third one direct flotation of baddeleyite is performed from the underflow product. The following reagents were used for flotation: of phosphate type (sodium tripolyphosphate, mono and diethers of alkylphosphpric acid) and sodium xanthate as collector for sulphides. The given set reagents provides for high effectiveness of flotation due to selective of collectors and presence of froth layer with high carrying ability. New flotation technology of recovering of baddeleyite from complex ore was developed and applied at the Kovdor Mining Plant, using AKER flotation machines.

Jan 1, 1995

By V. M. Johnston

The most abundant fuel resource in the U.S.A. is also the most under-utilized. Proven reserves of bituminous coal, sub-bituminous and lignite constitute from 60% to 90% of our total fossil fuel reserves -- dependent upon the parameters used by the analyst making the estimate. Despite this ample supply, bituminous coal provided only 20% of U. S. energy consumption in 1967 and 1968, this dropping to 17.57 in 1971 and 1972. By 1978, according to my projections, 16.7% of the Nation's mechanical energy will come from bituminous coal. However, our energy needs are growing at such a rate that the 20.6% provided by bituminous in 1967 equalled 480 million tons while the 16.7% of U. S. consumption visualized for 1978 will require nearly 650 million tons. In order to view coal's position with perspective in this developing energy crunch, it is necessary to examine the total energy situation. To this end, I have prepared a couple of tables which you should have before you. I chose this procedure rather than slides because I would need to utilize an entire wall to make the data visible to an audience. Therefore, I refer you to the long sheet entitled "U. S. Energy Consumption - Trillion Btu - 1967-1978." As you can see from the heading, I am confining my treatment of the problem to the intermediate term. In the long run, if we are willing to pay the cost, we can do a lot of things, including the complete conversion of coal into a sulfur-free fuel.

Jan 1, 1973

By Walter N. Campbell

The Simon Silver Mine is located near Mina, Nevada, approximately 50 miles northwest of Tonopah and 40 miles east of Hawthorne. It is an old property which was last worked in 1932 and closed operations due to problems arising from low metal prices. Federal Resources Corp. acquired the property in 1963 and undertook a completely new development program since the old surface plant and underground workings were beyond feasible repair. The deposit of silver, lead, zinc and copper is predominantly replacement of limestone. In the summer of 1964, a new surface plant was constructed and on December 2, 1964, sinking of a three compartment vertical shaft started and was completed to a depth of 1088 feet in April of 1965. Following the sinking program an 850 foot crosscut was driven to intersect the mineral zone on the 1000 level after which drifting, crosscutting and raising totaling some additional 4280 feet has been completed along with considerable diamond drilling and long holing into the walls. To date, two ore bodies have been encountered and test stoping operations are underway together with development of the 800 level for servicing, ventilation and access. The present development of ore is directed towards substantiating sufficient reserves to warrant the construction of a flotation mill.

Jan 1, 1967

By Nan Hua

As a high production and high efficient mining method, top coal caving method is now widely used in China. However, as more extra-thick coal seams are mined, it becomes more and more difficult to make the top coal fully broken up, resulting in more and more top coals flowing into the gob, rather than onto the rear AFC at the working face as designed. This research is aimed to investigate the failure mechanisms of the extra-thick top coal caving mining method.

Jan 1, 2009

By Richard E. Gertsch

A century of experience with mechanical excavation machines is beginning to pay dividends to the mining industry. Mining is moving from mechanical excavators to mechanical miners. These mechanical mining systems are poised to make a significant impact on hard-rock mining, both underground and surface. Mechanical mining machines have had a long and successful career in coal and evaporites ("soft-rock") mining. Unlike most mechanical hard-rock mining, these systems actually mine ore. For example, the most productive underground method has been, arguably, longwall mining. Mechanical excavation machines are mostly used in civil tunneling or in driving mine openings such as vent shafts. Civil tunneling is a notable mechanical excavation success. Even with its high capital cost, a tunnel boring machine (TBM) can drive kilometers (miles) of tunnel at very low cost. In hard-rock mining, mechanical excavators bore tunnels, raises and shaft openings in the mine, but rarely mine ore. Like the soft-rock miners, their contribution to mining is important and their development must continue. Generally, they are used as excavators not miners. Current trends guarantee development of true general-purpose hard rock mechanical mining machines. Mechanical miners will become a complete mining system and will determine the design of the mine. Mechanical methods will reward the operator with lower costs and high productivity.

Jan 1, 1992

By Shiou-Chuan Sun

This paper is to be presented at the Annual Meeting of the American Institute of Mining, Metallurgical and Petroleum Engineers, New York, New York, February 18-22, 1962. Permission is hereby given to publish with appropriate acknowledgments, excerpts or summaries not to exceed one-fourth of the entire text of the paper. Permission to print in more extended form subsequent to publication by the Institute must be obtained from the Secretary of the Institute. If and when this paper is published by the Institute, it may embody certain changes made by agreement between the Technical Publications Committee and the author, so that the form in which it appears here is not necessarily that in which it may be published later.

Jan 1, 1962

By J. G. Pippenger

Rio Tinto Coal Australia (RTCA) developed Meandu Mine in Queensland, Australia in 1983 to supply thermal coal to the adjacent newly constructed Tarong Power Station (TPS). In designing the mine, RTCA selected Meandu?s best economic reserves for a 25-year life based on station owner Tarong Energy Corporation?s (TEC?s) estimated life for TPS. That 25-year plan changed dramatically in the early 2000s when TEC approved life extensions to TPS?s four existing units plus construction of a fifth unit. After reviewing Meandu?s remaining reserves, RTCA decided the nearby Kunioon reserve offered the more economic option for maintaining deliveries beyond 2010. Those plans changed yet again in 2007 when TEC chose to purchase the Meandu Mine and nearby reserves rather than extend RTCA?s contract. TEC then selected Thiess Pty Ltd (Thiess) to continue operating Meandu until the new mine at Kunioon could be developed.

Jan 1, 2011

By K. Getsos

Western Greece is a favorable site for exploration and discovery of oil fields. The most important potential source rocks seem to be all the rocks deposited before middle Jurassic under special circumstances, such as reducing conditions, which allowed preservation and maturation of the organic material. In general all the rocks of middle Jurassic to Paleogene are not favorite source rocks. The porosity type was studied on fifty samples using scanning electron microscopy (SEM). Potential reservoir rocks are the porous Paleogene wackestones-packstones with boring, channel and vuggy porosity type. Finally seal rocks are the impermeable mud-stones and wackestones of Jurassic, Cretaceous and Paleogene age. These rocks consist of micrite and whole sells of foraminiferas and the porosity type is mainly intercrystal/interparticle. A Total Organic Carbon (TOC) analysis, conducted on seventy samples using a wet oxidation method, has revealed an extremely low TOC content (less than 0.05 %). This amount is by far less than the minimum organic content amount, required for source rock characterization and characterizes all the rocks of middle Jurassic to Paleogene age. Additionally, 18O and 13C stable isotope analysis was contacted and the results are given in d values. All the rocks within the studied time interval have much lower d values than petroleum source rocks. Clay mineral content was studied in almost seventy samples. As is indicated by the clay mineral content the studied rocks have reached up to the Middle Diagenesis and the temperature during diagenesis was rather low.

Jan 1, 2006

By H. A. von Schonfeldt, H. Douglas Dahl

INTRODUCTION During the past decade, significant pro¬gress has been made in applying rock mechanics principles to mine design problems by a great number of researchers. Some of these new techniques have found their way into the engineering and planning offices of the operating mine. In spite of these advances, however, the application of rock mechanics in the day-to-day mine planning and design of our domestic coal mines is rela¬tively rare. There are a number of reasons responsi¬ble for this relatively slow progress, not the least of which is the question of how to measure the success or cost effectiveness of a sizable rock mechanics effort in an opera¬ting mine. Firstly, the properties of geologic materials generally vary over a wide range and it is, therefore, difficult to assess whether an improvement in the mining conditions is due to a design change or due to a change in the geologic conditions. A second reason for the slow acceptance of rock mechanics in engineering thinking is the fact that some of the concepts are quite difficult and that physical evidence of their validity to mine design is still rare. Thirdly, com¬munication between research, engineering and applications oriented people appears to function only intermittently. In our view, however, the most important impediment lies in the "state-of-the-art." Exactly how much can rock mechanics help the mine operator? The best that rock mechanics can do at present is determine whether one approach is better than another when weighed against some design objective (stress, strain, deformation). We cannot determine the abso¬lute best ground control design -- only what is better. If ground control is lost, the statement that "it's the best one we looked at" means very little to the harried operator. While the "state-of-the art" has advanced a great deal, it has certainly not been reduced to an engineering matter in that design hand¬books are available -- they are not. The success of a rock mechanics program, there¬fore, can be determined only over a long period of time of continuous effort.

Jan 1, 1977

By L. B. Rothfeld

This paper presents preliminary results of a Bureau of Mines study of potential costs of compliance with the federal Resource Conservation and Recovery Act for copper heap and dump leaching. Specifically, estimates are given for the cost of compliance with possible technology standards that would require the use of liners and closure caps regardless of terrain and underlying geology and hydrology. This cost is compared to the co lit of compliance with present state requirements for terrain a typical of those found at existing copper leach sites in the Southwestern U.S.A. Incremental compliance costs are found to widely exceed screening criteria used by the Environmental Protection Agency to denote significant economic impact.

Jan 1, 1993

By Gregory M. Rumbaugh, Todd Kostecki, Christopher Mark

From 2015 to 2021, five massive pillar collapses occurred at four underground stone mines in the eastern United States. These events resulted in powerful airblasts that damaged mine infrastructure and mobile equipment, seriously injured miners, and disrupted underground travelways. Each of these pillar collapses propagated through the overlying strata, causing a subsidence basin on the surface. Pillar collapses are particularly hazardous for miners because they can occur with little warning and can affect miners that are far from the pillar collapse area. The following case studies show that certain factors may increase the likelihood of a pillar collapse. For instance, each of the five events involved the collapse of at least twelve benched pillars with width-to-height ratios (w/h) of 0.8 or less. This study elaborates on

By Charles Bruce

Three years ago, at a reception given during the Steel Institute meeting in New York, I heard the remark, "A new formula must be found for foreign investment." This was immediately following the takeover of U. S. Steel's Matilde operation in Bolivia. Recently, at the World Mining Congress in Lima, Peru, the subject of foreign investment was still a lively topic of conversation. The nationalization of the copper mines in Chile and recent trends in the "Third World" have made all but a few extremely wary of investment anywhere other than in the ?stable? countries. Now, the fallibility of this philosophy has been demonstrated in such "stable" countries as Canada, Australia, and Ireland. Yet, nationalization is not new to us. The events in Chile were classified as disastrous to the affected companies, but so were the effects of nationalization to the majors in Bolivia in 1952. Mexicanization of the mining industry in Mexico was considered impractical by many. Now, those who accepted it are finding it to be workable.

Jan 1, 1975

By D. L. Leach

This report covers laboratory experiments simulating in situ copper recovery from primary sulfide ores in sulfuric acid systems pressurized with oxygen. Copper extraction and acid consumption data are correlated with temperature in the range 50-150°C and quenched pH in the range 0.25-2. Adverse changes in the chemical composition of the leach solution and the formation of gangue-mineral alteration products and secondary sulfides can severely limit the extraction of copper above 90°C. Keeping the pH below the self-buffered value of about 2 and the temperature below about 110°C produces the maximum extraction rates. Forcing the pH too low not only results in excessively high acid consumption but may also limit the extraction of copper at temperatures above 100°C.

Jan 1, 1975

By Charles L. Kimbell

The year 1988 for the minerals indus¬try was one of favorable worldwide economic conditions for continued, rationally constrained growth. There was continued improvement in relations between market economy nations and the Soviet Union and China. The "shooting war" between Iran and Iraq ended. Soviet troops withdrew from Afghanistan. And conditions were generally favorable for economic growth in developed market economy countries. These favorable conditions were darkened only somewhat by the continuing foreign debt crises discernible in some major mineral producing developing market economy countries. However, there were situations developing that became major headlines in the late spring - situations that may have pronounced effects in 1989. The most significant event is the muddled situation in China. There is a good chance of worsening international relations and consequent restraint of development projects that could prove beneficial to China and her international partners. Of only slightly lesser evident significance was the death of Ruhollah Khomeini in Iran. This could lead to a variety of paths for the new Iranian leaders. Continued outbreaks of ethnic unrest in the Soviet Union clearly presented problems to the Gorbachev regime. This unrest has raised questions of how far the doctrines of "glasnost" and "peristroika" would be extended, including extensions into the minerals field. Another area of unrest is Panama with its tainted election and the Western Hemisphere's obvious dissatisfaction with the Noreiga regime. While not a direct threat to any major mineral industry enterprise, the political situation certainly presents a potential threat to the Panama Canal. That threat would have considerable impact on world

Jan 1, 1989

By H. Sevim

The utilization of high sulfur Illinois coal by utility plants has been decreasing since the enactment of 1990 Clean Coal Air Act Amendment. Illinois coal producers can make their coal saleable by offering the choice of taking the combustion by-products from the utility plants and placing them in the abandoned sections of their mines. To be competitive, however, coal producers need to select an environmentally acceptable transportation-handling-placement system through which the cost-per-ton of by-product disposed can be minimized. In this paper, a few such systems are presented. The favorable operating range of each system is determined in terms of distance and tonnage. A case study is given whereby cost analysis is conducted for an underground coal mine receiving by-products from two Illinois utility plants.

Jan 1, 1997

By B. Mirabile, B. Stables

Standing support is often used in conjunction with underground retreat mining. Knowledge of the load-displacement behavior of a standing support, and loading induced by the mine opening is critical to proper support selection. The NIOSH STOP database contains load-displacement laboratory test data for most commonly used standing supports. Hydraulic load cells currently used to measure in-situ loading of standing supports have exhibited leakage under load, producing irregularities within the dataset. An improved hydraulic load cell eliminates leakage and produces more consistent data. INTRODUCTION A hydraulic load cell, more commonly known by “flat jack” or JackPack, is a device installed to determine the loading characteristics of roof to floor supports. These standing or roof to floor supports include, but are not limited to: pumpable cribs, cans, wooden cribs (4-point, 9-point, etc.), metal props, wood timbers, concrete donut cribs, and other variations of these standing supports. Flat jack devices have been used previously to determine the loading of such roof to floor supports. The most commonly used load cell for standing supports is based on a design intended for pre-stressing standing supports, not load measurement. These load cells are produced in South Africa, and can be formed into several different shapes depending on the applications (Barczak). Flat Jacks are manufactured in various shapes and sizes depending on the application, common shapes are square and round that are 25.4 mm (1.0 inch) thick when collapsed as shown in Figure 1. The sheet metal that makes up the bladder is comprised of 19 gauge or 1.11125 mm (0.04375 inch) thickness, the top and bottom pieces of sheet metal are resistance seam welded around the perimeter. There are two different ports installed on one of the bladder skin corners of the flat jacks; these ports allow a fluid to fill the unit and the other port has a relief valve. The fill port is comprised of a check valve. The pressure relief valve is located in the second port; preset to 1724 kPa (250 psi), pressure relief valve will keep the load cell from bursting. Bursting of these load cells typically causes a small tear in the metal skin allowing the fluid to leak out without a large catastrophic failure. The effective inflation range of these load cells is between 25.4 mm (1.0 inch) to 254.0 mm (10.0 inches) thick. Different types of fluids can inflate these load cells but the most common and easily accessible fluid for testing applications is water. Water pressure from the mine supply line can inflate these load cells to the desired load. Depending on the pre-stressing requirements a pneumatic powered pump, hydraulic pump or hand pump may be required to inflate the load cells.

Jan 1, 2019

By M. Gunter, M. Buzon, B. McNamee

"A Google search on talc asbestos will yield over 500,000 hits – the reason being the growing number of civil lawsuits in this area. Historically the litigation was centered on amphibole-containing industrial talc. There was no debate these talcs contained amphiboles, but the issue was the definition of asbestos. Ultramafic hosted talcs, however, are formed in such a way as to not favor the formation of amphiboles in the talc; they can occur in the surrounding black-wall, also the serpentinite host rock is in direct contact with the talc. Thus allegations can be made non-asbestiform amphiboles or non-regulated serpentine group minerals can occur in the final products. INTRODUCTION Gunter (1994) wrote the following in regard to the question “What is asbestos? “The question yields different answers depending upon the audience. To a mineralogist, asbestos is a mineral form. To an engineer, it is an industrial material with several useful properties. To a medical doctor, it is an agent that might cause certain diseases. The third answer invokes several more issues: to a lawyer, a possible lawsuit; to a news reporter, a story; to an asbestos abatement worker, a job; and to a public school administrator or a parent, a nightmare.” The main function of that article was to try and provide background information to be taught at the college level to help students understand some of the issues associated with the use of asbestos in our modern society, and especially its use as a fireproofing agent in schools and public buildings. At that point in time one of the main issues was asbestos abatement as the mining and use of asbestos was waning as its health risks became more clearly known in the occupational setting. Now over 20 years later the current issue we are dealing with herein is “asbestos” occurring naturally in talc. This is a well know concern for those in the talc industry and they have been working on methods to ascertain if their products contained “asbestos” since last century. As such our articles will focus more on issues emerging from recent litigation, and the confusion that occurs, especially in the “asbestos” nomenclature as the mineralogist, engineers, doctors, and lawyers previously mentioned try to communicate. And lastly we need to remain cognizant of the fact that people are still dying of mesothelioma in the US. As a last resort to recoup expenses as they are dying they often respond to the TV advertisements we’ve all no doubt seen."

Jan 1, 2016

By W. M. Colwell

When it comes to the analysis of gold bearing ore, there are literally dozens of variables that contribute to the final "true value" of a given sample. Initial sample selection, splitting size and method, inherent nugget gold, pulverization method, and analytical method variations are but a few. However, it seems that the inherent nugget gold particle is targeted as the primary reason for intra and inter-laboratory variations in assay. The following study will show that this is not always the case. A series of tests were undertaken for the Aurora Partnership-Aurora Project to solve inter-laboratory variations in the analyses of blasthole cuttings. Initial concern was centered on the probability that free gold occurrence was resulting in erratic results for the mine's cyanide shake assays and outside laboratory fire assays. Comparison of fire assay and cyanide shake assay was sporadically consistent with previously demonstrated extraction percentage for the cyanide method. The goal was to delineate the factors that ensure consistency in analyses; implement, where needed, Good Laboratory Practices; and reestablish acceptable analytical method correlation.

Jan 1, 1993

By D. R. Nagaraj

Based on our finding that commercial copper chelating solvent extractants such as LIX65N® and LIX63® are excellent collectors for copper minerals, a detailed study was made using several water-soluble chelating agents belonging to the class of aromatic hydroxyoximes and having a gradual structural variation. A basic study of the system salicylaldoxime-tenorite was also carried out. Microflotation tests as a function of concentration of oxime, pH, addition of copper etc., using oxidic copper minerals such as chrysocolla and tenorite, and batch laboratory flotation tests using synthetic mixtures of quartz and oxidic copper minerals were carried out. The studies were aimed at an understanding of the collector function of the hydroxyoximes and of the general flotation behavior in these systems, in addition to studying the structural aspects of oximes vis-a-vis flotation. The results have demonstrated that all of the hydroxyoximes studied here have comparable collector property, and in all cases the oxime was found to be partitioned between the mineral surface and the copper in the bulk aqueous phase in the form of a bulk copper chelate. The occurrence of the latter could be accounted for by the formation in the bulk phase of a chelate between oxime and copper released from the mineral and/or by the detachment of the surface chelate. The role of surface and bulk chelates in flotation is discussed based on the results of partitioning of chelating agent into bulk and surface chelates in the system salicylaldoximetenorite. The effect of substitution of CH2 groups or benzene ring in the chelating agent molecule on its collector property is also discussed, in addition to the finding that only the anti-isomer has the ability to collect.

Jan 1, 1979

By S. J. Schatzel, K. M. Ajayi, Z. Khademian

The integrity of unconventional shale gas well casings positioned in the abutment pillar of a longwall mine could be jeopardized by longwall-induced deformations. Under such scenarios, the surrounding fracture networks could provide pathways for gas flow into the mine creating safety concerns. To provide recommendations for developing guidelines that ensure a safe co-existence of longwall mining and unconventional shale gas production, this study evaluates the impact of parameters that could affect potential shale gas flow into the mine in the event of a casing breach using a discrete fracture network (DFN) model. These parameters are evaluated using a conceptualized DFN realization that is representative of the fractured zone in the overburden, and the range of parameter variations are within values validated with field measurements. The results show that a decrease in fracture aperture (potentially due to longwall-induced stress in the likely vicinity of the breach location) reduces the potential gas flow to the mine by a significantly higher proportion. A 50% decrease in the aperture of the fracture that directly transports the gas from the casing breach location reduces the gas flow to the mine by over 70%. Similarly, changes in the fracture water saturation level significantly affect the gas flow. In all cases, the potential gas flow to the mine is higher if the casing breach occurs at an increased gas well pressure. These findings provide critical information regarding the impact of each of the parameters associated with gas flow in the event of a shale gas casing breach near a longwall mine and could help towards the development of guidelines to ensure a safe coexistence of both industries.

Mar 2, 2022