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Joy Mining Machinery has developed a new generation of ultra-heavy shields for Anglo Coal Australia?s Moranbah North Mine in the Bowen Basin region of Queensland. These are the largest two-leg longwall shields yet produced by Joy. The longwall at Moranbah North posed a number of challenges, among them a thick, inclined, sometimes undulating seam with increasing depths. The result of this was the need for larger, heavier, more powerful roof supports. Knowing that future longwalls would be going deeper, mine management determined that shield yield ratings of at least 1,750 t (1,930 st) was what would be required.

Jan 1, 2011

By Julián M. Ortiz, Antoine Caté, Oy Leuangthong, Ilkay S. Cevik

Mineral resource classification relies on the expert assessment of a qualified person (QP) to determine which blocks of a 3D mineral resource model are classified as measured, indicated, or inferred. The decision is often based on a combination of quantitative parameters related to the estimation process and qualitative decisions based on previous experience or preconceptions not captured in the numerical model. As such, the procedure is subject to inconsistency, that is, blocks with similar qualities may end up in different categories, mainly due to the subjective nature of the approach. In this paper, we present a methodology to assist the qualified person in this task by clustering blocks with similar parameters and then classifying them into categories in a consistent and automatic manner that only requires the specification of a few hyper-parameters. The result is a consistent classification into resource categories comparable to the result of a classification done by a qualified person but fully consistent and generated in a short time frame. The procedure begins with repeatedly sub-sampling the block model to determine a distance matrix using an unsupervised random forest approach and then clustering the blocks using the associated distance matrix. Then, all the blocks in the model are classified using a supervised random forest approach, which gives a probability of belonging to each class. The initial class can be determined from the class probabilities. Support vector classification with a radial basis function kernel is utilized to smooth the boundaries between classes and define the final classification. An approach to tune the hyper-parameters of smoothing is provided. The methodology is demonstrated with two examples from two gold deposits. Results are comparable to the classification done by the project qualified person using conventional methods.

Aug 17, 2021

By S. K. Kawatra

Under normal conditions, a significant amount of pyrite is recovered in the froth during flotation of high-sulfur coal. In order to reduce this pyrite recovery, it is first necessary to determine the primary recovery mechanism, as different measures are required for reducing entrainment, locked-particle flotation, or true hydrophobic flotation. In this paper, evidence is presented which suggests that hydrophobic flotation is not the major mechanism for recovery of liberated pyrite, and that the bulk of the recovered pyrite is there either as a result of simple entrainment or by being physically locked with floatable coal particles.

Jan 1, 1991

By Dale W. Norris

United States Steel's Cumberland Coal Operations is located in Greene County in the southwest corner of Pennsylvania. The mine and related facilities have been in operation since September of 1977. Production from this mine, U. S. Steel's first commercial coal mining venture, will eventually reach a level of 2.72 million mt of clean coal per year and is totally committed to electric power generation. Cumberland is a slope mine in the Pittsburgh seam and is mined by continuous mining machines and longwall. The coal from the mine is trans- ported by belt to the surface, taken through a rotary breaker for initial preparation, and stored in raw coal silos. It is then processed through the preparation plant and taken to a clean coal silo where it is held for train loading. Cumberland Mine operates its am 28.16 km railroad to transport the coal to the Monongahela River. The unit train consists of thirty-one 90 mt cars. The coal, once loaded on barges, is then shipped to the customer. Cumberland Mine is one of the most modern coal preparation and unit train loading systems in the nation. The preparation plant is de- signed to receive coal from the silos at a rate of 720 at per hour. The +6.35 mm material is screened out and cleaned in a Daniels heavy media vessel with two 3.35 m weirs. Minus 6.35 mm material is fed to sixteen #88 Deister concentrating tables. The cleaned coal from this circuit is dewatered, and all effluents from the mechanical dewatering report to the classifying Cyclone sump for classification through ten 35.6 cm cyclones. The cyclones overflow material (-150 mesh) is processed through two banks of three 8.5 m3 Denver D.R. flotation machines. The cyclone underflow pro- duct (28-1 0 mesh) is processed in two banks of 5 six 2.83 m Denver Sub A machines. The clean flotation product is then dewatered in Bird screen bowl centrifuges, blended with the other clean coal size fractions, and the total plant product further dewatered in a thermal dryer.

Jan 1, 1980

By A. R. Hollbach

This paper presents a succinct overview of the Canadian coal situation. The topics treated specifically are: the rates of growth of coal supply and demand; the relationship between the coal and electricity generation industries which form its dominant market; the unique impact of nuclear generation on coal demand in Canada; and finally, a view of the developing technologies which will create opportunities for growth in the coal industry of the future. Resources The most important element of coal supply is the resource. The disposition of Canada's coal resources has a marked effect on their utilization, since industry in Canada has not generally developed around coal-fields. The distance from the major industrial centres of Ontario and Quebec to the major region of coal supply in Alberta and British Columbia has crested an economic barrier to the expansion of the use of domestic coal.

Jan 1, 1985

By Raymond L. Zahradnik

Marco Polo reported that the Chinese used "black rocks" for fuel, and recent studies indicate that the Chinese may have used coal in small amounts for two or three millennia previously. The use of coal as a major source of energy however, did not begin until about the twelfth century, when the inhabitants of the northeast coast of England discovered that certain black rocks found along the seashore--and thereafter known as "sea soles" would burn. Since this initial discovery, coal has been mined continuously, first in England and shortly thereafter in present Belgium, France, and Western Germany, and finally in all coal-bearing areas of the world, in ever increasing amounts. The production of coal in the United States began about 1820, when 14 tons were reportedly mined. Since that time the production of coal increased steadily until about 1907, after which the rate has fluctuated between the extremes of about 400 and 700 million tons per year. Bituminous coal and lignite production was 590 million tons in 1974. Value of production was $8. 9 billion. Anthracite production was b.3 million tons with a value of $157.5 million.

Jan 1, 1975

By R. Asamoah, P. Forson, W. Skinner, M. Zanin

Despite the seeming benefits decoupling pyrite and arsenopyrite minerals present in practice, little success has been achieved. The present study presents possible process routes for attaining selective flotation broadly capitalizing on differential oxidation between these minerals, and the use of a chelating collectors. The best performance was achieved with dithionocarbamate application following copper activation, yielding 81.4% arsenopyrite and 37% pyrite recovery. Preaeration followed by staged addition of xanthate produced 76% arsenopyrite and 31% pyrite recovery while reverse flotation of pyrite after H2O2 addition gave rise to rejection of 66% pyrite accompanied with 24% arsenopyrite.

Mar 2, 2022

By Long An, Chao Wu, Yuanhui Li, Xing Sun, Shuai Xu, Changyu Jin

Stage open stope mining (SOSM) maintains the stability of excavation openings by leaving a large number of rib pillars. Affected by the strong unloading due to stage mining and the low width-to-height (w/h) ratio of the pillars remaining, largescale destabilization disasters of rib pillars or excavation openings easily occur when the distribution of ground stress or the size of rib pillars is unreasonable. In view of these problems, a physical SOSM model test was carried out based on an underground metal mine in Chifeng City, China, revealing the deformation and failure characteristics of the SOSM pillar group by overloading. The physical model test results of SOSM and room-and-pillar mining (RPM) with a weak pillar were compared, and the failure process of the SOSM pillar group showed the characteristics of rapid and severe damage. The strength difference between a weak pillar and the adjacent pillars enhanced the stress rebalancing effect and extended the failure process of the pillar group. Similar to the SOSM pillar group with a low w/h ratio, some high-strength pillars can be used to avoid large-scale destabilization disasters caused by the synchronous failure of pillars.

Mar 8, 2023

By Manuel S. Rivera

Abstract. Instrumentation in concentrators has evolved from a few isolated indicators to compu- terized control within twenty years. This evo- lution has caused a drastic change in the phil- osophy, personnel and equipment used in a pro- gram of servicing and utilization of present day automation.

Jan 1, 1980

By R. Hogg

A standard procedure for determining size-specific gravity distributions of fine coal (including the -400 mesh fractions) by sieving and centrifugal sink-float separation is described. The significance of using a centrifugal sink-float technique and the effect of the magnitude of the centrifugal force on the separation of fine coal are confirmed in the present study. The relative merits of cumulative versus incremental sink-float are discussed. The procedure is evaluated quantitatively using data obtained for the products of froth flotation of -100 mesh coal.

Jan 1, 1994

By A. J. Guse

The primary limiting factor for hoisting capacity from great depths is the self-weight of steel wire ropes. Steel wire ropes are very suitable for mine hoisting due to their high strength and durability, but have the negative characteristic of a low strength/weight ratio. Also, as hoisting depths increase, the service life of steel wire ropes decreases due to the higher stresses and physical effects on the ropes. The significantly higher strength/weight ratio of synthetic ropes offers the primary advantage of hoisting a larger payload with a similar size rope and hoisting plant. The beneficial properties of synthetic ropes could be used to improve the overall economics of deep underground mining both for new deep shaft projects and for existing mining operations expanding to deeper orebodies. A research and development program has been initiated to evaluate the suitability of a fully synthetic rope for the mine hoisting application.

Feb 23, 2014

By Herry Poernomo, Agus Prasetya, Iga Trisnawati, Himawan Tri Bayu Murti Petrus, Gyan Prameswara, Panut Mulyono

We studied yttrium extraction from untreated zircon sand processing waste tailings. Xenotime mineral as the rare earth element source with an abundance of yttrium (REY) was detected in sufficient grade for extraction. As much as 9.03% yttrium exists in zircon tailings (analysed by X-ray fluorescence spectrometry). The presence of yttrium was confirmed by X-ray diffractometry in xenotime minerals, which are yttrium carriers (Y-PO4). The purpose of this research was to determine the effect of leaching conditions on yttrium recovery from zircon sand after alkaline fusion treatment. Alkaline fusion was chosen to decompose phosphate into hydroxide in the xenotimemineral,which will reduce further required hydrometallurgical processing.Alkaline fusionwas carried out for 3 h at 450 °C, with a ratio of sodium hydroxide to zircon tailings sand of ~ 1:1. The alkaline fusion product was leached with water, followed by hydrochloric acid treatment to leach the yttrium. Yttrium recovery reached 87% under optimum conditions (60 °C, 1MHCl, and solid-to-liquid ratio = 1/10 for 7.5 min). A suitable model for yttrium dissolution with hydrochloric acid was diffusion through a solid particle ash layer. The calculated activation energy (EA) for this model was 20.21 kJ/mol.

May 26, 2020

"The adsorption of mixed cationic/anionic surfactants with different molar ratios onto quartz was investigated. The cationic surfactant used was dodecylamine bromide (DDA), and the anionic surfactant was sodium oleate (NaOL). The critical micelle concentration values for the individual surfactants and their corresponding mixtures were determined using a platinum plate. The adsorption mechanisms of mixed surfactants on quartz were studied using contact angle measurements, flotation tests and adsorption amount measurements. At alkaline condition, NaOL depresses DDA flotation of quartz without depressing the adsorption of DDA. The molar ratio of mixed surfactants is found to be a key factor in the orientation of alkyl chains and thereby the flotation response of quartz. A mixture of 1/2 or 1/3 DDA/NaOL forms on the surface of quartz when the concentration of NaOL is higher than that of DDA. The adsorption of the mixture decreases the wetting of quartz since the alkyl chains are in chaotically orientation with a conceivable number of head groups directing towards the solution phase. These results provide important insights into the adsorption of mixed surfactants onto quartz surface. INTRODUCTION Froth flotation is known as an effective method of separating mineral particles on the basis of their surface chemistry, specifically their hydrophobicity. [1]. The hydrophobic particles will attach to the bubbles and rise to the top of the containing vessel to form a froth that flows over the lip of the vessel. The hydrophilic particles remain in the liquid [2]. In the process, surfactant is often used as collectors for surface modification in order to change the wetting properties of mineral particles. The primary long chain alkyl ammonium salts are the most widely used as collectors for the flotation of oxide minerals, such as quartz, muscovite, hematite, phosphate and feldspar [3, 4]. Adsorption mechanism of alkyl ammonium salts on oxide minerals has been extensively analyzed [5, 6]. Generally, the ammonium salts are adsorbed through electrostatic interaction of the polar group of the molecules with the surface of these minerals [7]. Despite many obvious advantages of the ammonium salts in low temperature resistance and hard water resisting, however, their unavoidable drawbacks, such as high sensitivity and poor selectivity for slimes, relatively high cost, have limited their applications [8]. In recent years, mixed surfactants have drawn much attention due to their superior physicochemical and surface properties than single surfactants [1, 9-11]. They have been used in many industrial processes such as dispersion/flocculation, flotation, detergent, corrosion inhibition, cosmetics, foods, paints, chemical mechanical polishing, enhanced oil recovery, and nanolithography [12]. Most of the mixed surfactants have synergistic advantage in reduction of the surface tension and critical micelle concentration (CMC); therefore, they exhibit spurious properties, like excellent surface/interfacial activities, and are less expensive than single mixed surfactant systems [13, 14]."

Jan 1, 2016

By Stephen W. Kline

Rock suitable for crushed-stone aggregate is almost entirely restricted to the Highlands region of Arkansas, mostly from Paleozoic sedimentary units, but also from a few Cretaceous igneous plutons. Reserves in the state are sufficient for local needs, and Arkansas is geographically well situated for export markets to the south, where resources for crushed-stone aggregate are lacking. A study of 423 quarries, test pits, and exploration sites in Arkansas has been completed to evaluate the relative quality of bedrock units for producing crushed aggregate. Of these, 274 sites have records of engineering tests for stone evaluation done by the U.S. Army Corps of Engineers and/or the Arkansas State Highway and Transportation Department (AHTD). Of the 1,775 sample records from these sites, the most commonly reported parameters are the LA abrasion test and the Na-sulfate soundness test. Many records also have absorption and specific-gravity data, and, for some, petrographic information helps identify the potential for alkali-silica reactivity in portland-cement concrete. By determining the bedrock sources of the tested samples, comparison is made between the various geologic mapping units as to their relative quality for crushed stone.

Jan 1, 1999

By M. F. Vancas

The San Manuel oxide ore reserve ranges in depth from being exposed on the surface to lying 1000 ft. beneath a conglomerate layer all of which is confined in the subsidence zone of an active sulfide block caving operation. Present day recovery of the oxide copper values is either by open pit mining-dump leaching, or in-situ leaching of the oxide ore using dilute sulfuric acid solutions and solvent extraction/electrowinning processing of the pregnant leach solutions. Future plans are for continuation of leaching with expansion of reserves and increased processing rates. The state of the mining industry and copper in particular has not been good for a number of years. All of the producers that are still operating have made major adjustments in order to remain competitive. Magma Copper Co. is no exception.

Jan 1, 1987

By Bruce H. Mason

Lightweight aggregates are classified as those minerals, natural rock materials, rock-like products, and byproducts of manufacturing processes that are used as bulk fillers in lightweight structural concrete, concrete building blocks, precast structural units, road surfacing materials, plaster aggregates, and insulating fill. Other uses include architectural wall covers, suspended ceilings, soil conditioners, and other agricultural uses (Mason, 1989). One unusual agricultural use recently reported was for bedding on a crocodile farm on the south coast of Natal. It seems that female crocodiles became upset because there was no vermiculite in which to lay their eggs due to the late arrival of a consignment of vermiculite. The vermiculite was being used as a substitute for river sand to nest crocodile eggs (Griffiths, 1989). The various lightweight aggregate materials may be classified into four groups as follows: 1. Natural Lightweight Aggregate Materials-prepared by crushing and sizing natural rock materials, such as pumice, scoria, tuff, breccia, and volcanic cinders. 2. Manufactured Structural Lightweight Aggregates-prepared by pyroprocessing shale, clay, or slate in rotary kilns or on traveling grate sintering machines. 3. Byproduct Lightweight Aggregates-prepared by crushing and sizing foamed and granulated slag, cinders, and coke breeze. This group of lightweight materials, with the exception of slag, has become less significant and will not be discussed in this chapter. Other lightweight aggregates are beginning to appear in the marketplace. Some are the result of manufacturing processes on industrial byproducts and/or waste products, such as fly ash and incinerator residue (Bigner, 1992). 4. Manufactured Insulating Ultralightweight Aggregates-pre- pared by pyroprocessing ground vermiculite, perlite, and diatomite. The application of diatomite in brick and in extruded and aggregate forms has declined in recent years (Kadey, 1983) and will not be considered in this chapter. Lightweight aggregates for structural concrete and concrete masonry units, according to the American Society for Testing and Materials (1986) consist of "aggregates of low density used to produce lightweight concrete, including: pumice, scoria, volcanic cinders, tuff and diatomite; expanded shale, clay, slate, perlite, vermiculite or slag; and end products of coal or coal combustion" (Mason, 1989). Lightweight aggregates are distinguished from other mineral aggregate materials by their lighter unit weights-1 281 to 1 602 kg/m3 or less for loosely packed lightweight aggregates-as com- pared to 2 002 kg/m3 or more for crushed stone, sand, gravel, air-cooled slag, and other common mineral aggregates. The specific gravities of these lightweight aggregates are also used to classify them for use in concrete; they range from the extremely light materials, used for insulative and non-structural concrete to expanded shale, clay, slate, and slags used for structural concrete. Vermiculite and perlite are sometimes referred to as super light- weights. Insulating concrete (non-load bearing) weighing as little as 240 kg/m3 can be made with these aggregates. Natural aggregates such as pumice, pumicite, and scoria are normally made into concrete weighing about 400 to 480 kg/m3. Expanded shale, clay, and slate produced in a rotary kiln make structural concrete ranging from 1 201 to 1 842 kg/m3. Expanded shale and clay produced by sintering make concrete that ranges from 1 442 to 1 922 kg/m3. Air-cooled slag produces concrete ranging from 2 162 to 2 403 kg/m3. The low density lightweight aggregates are used primarily for insulating purposes. They have relatively low compressive strength. The middle density aggregates are used for insulation and for fill. Those at the upper end develop excellent compressive strength and are used in many structural applications (Anon., 1971). In recent years, the production of lightweight aggregates in the United States for all uses (including insulation and construction materials) has averaged about 19 Mtpy (Table 1). The production and consumption of lightweight aggregate is closely tied to the fortunes of the construction industry and the need to construct energy efficient buildings. Recent years have seen the production of lightweight aggregate approach the levels of the early 1970s. The period of 1979 to 1981 was a low point in production levels. The low levels of production were caused by significantly higher plant energy costs due to the large amounts of fuel and energy used in the production of most types of lightweight aggregate. Lower levels of construction activity also affect production levels. This chapter focuses on the use of natural lightweight aggregates and manufactured insulating ultralightweight aggregates, and on both the production and use of manufactured structural light- weight aggregates. Some additional comments are made on byproduct materials. Separate commodity chapters on vermiculite, perlite, pumice, and volcanic cinders are elsewhere in the volume. Discussion of the commodities covered elsewhere in the book will be limited to observations on their utilization and relation to other lightweight aggregate materials.

Jan 1, 1994

By Timothy F. Markey, Brian C. Strohm

This paper presents a case study which applies risk assessment techniques in evaluating potential environmental problems associated with past waste disposal practices at a 65 acre non-ferrous metals and metal alloys manufacturing facility. Waste management activities at the site involved a number of surface impoundments for gangue material, neutralized acid rinse waters, acid rinse sludges, demolition debris, storm water runoff, stockpiled ores, and a permitted residual waste landfill. As a result of these activities, the She contained 9 identifiable waste management areas impacted by over 35 potentially hazardous chemicals and metals. Extensive environmental data obtained from investigations at the Site revealed heavy metal and volatile organic chemical contamination in various environmental media. These data were utilized to evaluate potential risks to human health and the environment. The human health risk assessment estimated potential health risks to workers, residents, and Site trespassers under current and expected future uses of the Site. Areas of the Site were identified which were considered to present potential health concerns under the various exposure scenarios. Results from the human health risk assessment were utilized to develop cost effective risk based soil remediation goals protective of the public health and environment.

Jan 1, 1992

By Leandro Seixas Bicalho, Wagner Cláudio da Silva, Kelly Laranjeira Nunes, Lívia Marques Faustino

Seeking to implement the Global Industry Standard on Tailings Management to improve the safety of their tailings facilities across the globe, mining companies are motivated to invest in new technologies to recover valuable minerals from tailings. One solution being evaluated is the use of magnetic separators to concentrate ultrafine tailings. However, this approach is energy intensive as it requires high magnetic fields to recover ultrafines, and usually results in low mass yields. Additives that modify pulp rheology and surface properties, or selective flocculate ultrafine particles, were tested to enhance the performance of magnetic separation. Promising results in laboratory scale testing different types of additives confirmed that it is possible to increase the mass yield, keeping the selectivity of this stage.

Feb 1, 2024

By D. Yokom, T. Katsabanis, E. Tremblay

"The mining industry has always faced the problems of replacing retired mining professionals, retaining their knowledge, continuously developing the skills of local talent and employing under-represented groups. In expansionary scenarios the industry faces the additional challenge of increasing available talent. New talent has traditionally come from current mining programs; however, these programs have been declining in numbers, and those that remain face challenges such as fluctuating enrollments, and reduced budgets. Queen’s University and Northern College have partnered to develop an innovative new program that offers online mining education to engineering technologists seeking to upgrade their skills and obtain a Bachelor’s degree. The high quality, flexible curriculum, offered online, includes a wide range of learning activities that promote interaction (student-to-student, student-to-instructor, and student-to-content), and is enabled by modern learning technologies (an integrated learning platform, as well as a variety of types of purpose-built video, web conferencing, and simulation software). The program issues block transfer credit to college graduates, and consequently reduces the time to completion when compared to other Bachelor’s degrees in Mining. The curriculum has been carefully designed to enhance a balance of technical, managerial, and societal skills for students. The program also includes short summer field school sessions, where students gain practical application skills under the direct supervision of engineering experts. THE NEEDS OF INDUSTRY Canada is the world’s largest exporter of minerals, and the contribution of this sector to Canada’s gross national product is more than three times that of the automotive industry, representing approximately 4% of Canadian GDP (MiHR, 2015)1. According to a recent report by the Canadian Mining Industry Resources Council (MiHR, 2016)2, despite the recent downturn in commodity prices, the industry will continuously need to attract new engineers to replace talent retirements and prepare for the possibility of expansion when the industry recovers. As past experience indicates, the challenges during expansion times are severe and the effects on education counter-productive. For example, during the prolonged expansion cycle of 2006-2012, several new programs were started worldwide, and mining became the profession of choice for many young students. During the subsequent downturn in the industry, many of these programs face dwindling enrollments, placing their sustainability in question. However, there is a continual need by industry to retain employees, as well as attract and train local talent, while providing educational opportunities to its employees. High potential college graduates can find themselves reaching a ceiling in their advancement due to their lack of a University degree. Furthermore, there exists an under representation of women, immigrants, and Aboriginal peoples in the labour force, and engineering fields in general1,2. Traditional mining engineering programs have tried to respond to the needs of industry, as well as meet the needs of students seeking diverse and successful employment careers. These programs tend to cater to the educational needs and aspirations of a general population, and their ability to grow and respond to changing industry needs is constrained by the number of students they can attract, as well as the resources available to them in a steady-state scenario."

Jan 1, 2017

By Mason L. Dicks

For many years The Hanna Mining Company has been investigating the flotation of the non-magnetic iron ores located in the Western Mesabi Range of Minnesota.1 During the 1950's a number of anionic iron procedures were evaluated and in the late 1950's and early 1960's the anionic silica floats and the cationic silica floats were tested with improved results.2 The cationic float became more attractive and effective by the use of the improved ether amines. About 1962 a desliming process by selective flocculation was developed by the U.S. Bureau of Hines at Minneapolis', Minnesota.3, 4, 5 This is a very efficient method of desliming and was first tried with the anionic silica float and then the more practical cationic silica float. In the mid 1960's The Hanna Research Laboratory began studies to optimize the selective flocculation process for our ores. This was followed by studies to optimize the cationic silica float after desliming by selective flocculation. This testwork was done on large, 500 to 1000 tonne bulk samples of oxidized taconite which were later successfully piloted at .68t/h (1500 Lbs. /hr.). A program was then begun to test the oxidized portions of numerous taconite drill holes to outline the ore bodies and develop mining plans. This paper will discuss our optimization results of both the selective flocculation and the cationic silica float as applied to our various ores. In addition the pilot plant studies and drill core testwork will be discussed.

Jan 1, 1978