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By E. Ben-Awuah, H. Askari-Nasab, N. Al Habib

Open pit mines are getting deeper with time and transportation expenses are increasing because of the increasing haulage distance. In-pit crushing and conveying (IPCC) is getting popular in deeper open pit mines as a suitable alternative to truck haulage because it offers a lower operating cost due to shorter haulage distance and less truck requirement. Semi-mobile in-pit crusher, currently the most popular IPCC system, is relocated every two to five years and the short-term plan needs to be updated accordingly. Short-term planning with IPCC is an area of research that has not been explored extensively yet and hardly any model can generate short-term extraction sequence considering an IPCC in place. This research work proposes a mixed integer programming model to generate short-term production plan within a time horizon of 12 months. The objective of the model is to optimally allocate shovels to minimize cost of material handling and maximize revenue subject to meeting plant requirement, maximum allowable tonnage variation and IPCC location constraints to achieve production and NPV targets set by strategic plan. The proposed model has been implemented in a hypothetical case study for verification. The comparison of results between scenarios with and without IPCC is expected to justify the use of IPCC in large open pit mines from a short to medium term perspective. A semi-mobile IPCC system with one relocation is considered in the case study.

Feb 1, 2023

By M. Fan, Z. Long

"This paper presents some studies on recovering valuable elements from Chinese coal by-products, including coal combustion fly ash, stone coal ash, and coal flotation tailings. Both commercialized technologies and economic potential recovery methods are described in this study. Magnetically stabilized air-dense medium fluidized bed separation, tribo-electrostatic separation, froth flotation, and hydrometallurgical methods are discussed in recovering various valuable elements in Chinese coal by-products from different coalfields. These valuable elements include iron, carbon, aluminum, rare earth elements, lithium, gallium, germanium, uranium, titanium, scandium, silicon, vanadium and phosphorus, etc. The ultimate goal is to fully utilize all valuable elements in coal by-product. Each component within coal by-product should be efficiently segregated to its highest value. INTRODUCTION Coal is mainly composed of energy-producing elements carbon and hydrogen. In addition to these elements, coal usually contains many other valuable elements, including iron, aluminum, silicon, rare earth elements, lithium, gallium, germanium, vanadium, uranium, titanium, scandium, and phosphorus, etc. These coal-associated elements are significantly enriched in coal combustion by-product fly ash because of majority of main components, carbon and hydrogen elements, being removed. Table 1 provides the chemical composition range of the main elements oxides in 12 Chinese fly ash samples collected from coal power plants located in Northeast China, Northwest China, Southwest China, and Southeast China. It can be seen from Table 1 that the major mineral components of different ashes are similar, but the bulk chemistry of different fly ashes may vary widely due to the changes of ratios of the mineral components in different coals. The major mineral components in various Chinese coal combustion fly ash are silicates, iron oxides, and unburned carbon."

Jan 1, 2017

By Lewis V. Wade

This paper summarizes the results of the rock mechanics monitoring program performed as part of Old Ben Coal Company's longwall coal mining demonstration project conducted in cooperation with the United States Bureau of Mines. The work described herein included installation of instruments, collection of data and data analysis performed during mining of the first longwall panel in Mine No. 24. The rock mechanics monitoring program included both surface and underground instrumentation and was designed to achieve the following purposes: 1 -To provide the capability to observe unusual situations during mining so that remedial measures could be instituted quickly 2 -To formulate design guidelines for future longwall mining efforts; 3 -To evaluate surface subsidence, and its character, rate and potential effects on cultural features, and to develop criteria to assist in predicting subsidence for other mines having similar roof conditions. Six previous attempts with longwall methods in Old Ben Coal Company's Hine 21 had been unsuccessful due to roof control problems. A description of these attempts is given by Moroni (1973). In preparation for the present longwall operation a study was performed to review existing data on the previous unsuccessful attempts, to establish coa1-and floor-strata bearing capacities in Mines Nos. 21 and

Jan 1, 1977

By H. R. Coles

Test work conducted in the 6.4 and 10.52 m Aerofall Mills at the Iron Ore Company of Canada Carol Project showed that the conventionally used ?deflector?-type liners which form the basic principle of Aerofall Mill grinding did not necessarily provide the best grinding performance. A new design, using low profile liners incorporating radial ribs of a proper height, actually improved the mill throughput in the order of 9 to 20% without sacrificing grinding efficiency. In addition, the new design reduced liner weight and scrap losses, which resulted in a reduction of liner consumption by 25%. It provided better protection to the mill shell and reduced the overall maintenance cost for the mill

Jan 1, 1980

By M. Misra

Improved liberation and flotation of kerogen from eastern oil shale were accomplished with high-temperature grinding and a1 so with the addition of fuel oil during the grinding stage. Liberation measurements indicated that possible coalescence and aggregation phenomenon of kerogen particles during grinding may reflect this behavior. Additionally, ultrasonic treatment of the rougher concentrate prior to cleaning improved the quality of separation.

Jan 1, 1984

By Arthur W. Ruff

The iron-ore beneficiation and shiploading facilities of the Marcona Mining Company are at San Nicolas Bay which is on the Peruvian coastal desert about two hundred and seventy miles south of Lima. The mines are at elevation of 2,500 ft. Crude ore is transported from the Mine primary crushers to the beneficiation plants by ten miles of overland belt conveyors. After the predominantly magnetic ore is reduced to minus 3/4 in. in the secondary crushing plant, the ore is ground by rod and ball mills and concentrated with magnetic separators. The concentrate slurry is pumped to a thickening and filtering installation for desliming and dewatering. Pelletizing is accomplished with a Lurgi and also a Dravo-Lurgi machine. Deep-water shiploading facilities are available close to the beneficiation plants. Figure 1 shows a flowsheet of the general operation. Pelletizing operations are scheduled 24 hours a day and 365 days per year. A maximum tonnage rate with a high percentage of operating time is necessary to produce the three and one half million tons per year required from the two pellet lines. Process control is a major responsibility and of primary concern to all Operating personnel. The particle size, moisture, and chemical composition of the filter cake must be closely controlled to get uniform high-grade pellets. Key points are sampled routinely and analyzed on a two-hour basis to provide the necessary structure and chemical data to maintain a superior final product. The iron content of the pellets is held between 65.3 and 65.8 percent with 4.0 percent Si02. Sulfur is below 0.04 percent and copper is below 0.02 percent in the finished pellet.

Jan 1, 1968

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 T. Rudolph, M. Pawlik, J. Benndorf, X. Yin, J. F. Brune, P. Goerke-Mallet

The long and often undefined period in the post-mining phase challenges geo-monitoring with its various responsibilities, like the detection of environmental changes, ground movements and water management. Modern methods of geo- and environmental monitoring observe numerous aspects using active and passive sensors with multispectral, hyperspectral and microwave sensors, with diverse spatial dimensions and spatiotemporal resolutions from satellites, Unmanned Aerial Vehicles (UAVs), in-situ sensors. Data integration, together with on-site knowledge and experience, provides the basis for comprehensive modeling, which improves the understanding of the environmental changes and their related causes, which is an essential step for public acceptance. In this paper, we aim to give a brief overview of various geo- and environmental monitoring methods.

Mar 2, 2022

By S. S. Mauney

Natural and synthetic colors are used in almost every facet of our daily lives as a means of communication and expression. Natural ochres, umbers, hematites, and magnetites were once used in their crude or semi-processed state for their pigment value in construction products and low-end coatings applications, while yielding, in recent years, to synthetically produced iron oxides for more sophisticated products. Today, through innovative mining, processing, and marketing techniques, natural iron oxide pigments are once again gaining strong inroads into products and markets requiring precise chemical and physical characteristics. With our focus on environmental consciousness and resource conservation, value added natural iron oxides provide an economical and responsible alternative to our color needs.

Jan 1, 1993

By M. Solomon

Crushers are designed and manufactured to survive the severe duty of mining environments worldwide. Under these conditions the crusher performance and availability is one of the critical factors in the mine?s production and profitability. Traditionally the development of these machines tends to be experience-based, incremental improvements in design due to challenges of different applications, duty, or manufacturing. In order to better serve the mining industry a new approach was taken to the design of primary crushers. This approach was to focus on safety and maintenance activities. The result of this effort is a new generation of gyratory crushers that can be serviced from above. Using the features of this new generation of crushers to their fullest extent crushing installations have improved safety, reduced design and construction costs, and lowered maintenance requirements. This presentation explores the benefits of two crusher installations utilizing top service crushers.

Jan 1, 2010

By Mike Perkins

The Summitville Au-Ag-Cu district in the southeastern part of the San Juan volcanic field has been a major gold producer in Colorado. Mineralization is hosted by the composite South Mountain quartz latite porphyry volcanic dome, which is believed to have been localized by the intersection of the northwest margin of the Platoro-Summitville caldera complex and the northwest-trending Platoro fracture zone. K-Ar age dates indicate that alteration and mineralization were nearly contemporaneous with emplacement of the dome at 23-20 m.y. ago, 6-7 m.y. after collapse of the Platoroo-Summitville caldera complex. The dome consists of at least four major phases including strongly altered quartz latite porphyry; a late-mineral, coarse-grained sanidine quartz latite porphyry; and postmineral quartz latite dikes. The dome was emplaced into intracaldera rhyodacite and andesite. Gold-silver-copper mineralization is concentrated near the top of the dome and is associated with pods, pipes and steeply dipping tabular zones of silicification and advanced argillic alteration. Alteration is zoned outwards from the center of mineralization through argillically and propylitically altered rocks, and is largely confined to the area of the dome. Trace element geochemical patterns for the deposit indicate a central zone of anomalous As-Au-Pb-Ag and low Mn within an exterior zone of anomalous Ag-Au-Pb-Hg and high Mn. The chief ore mineral is native gold which is associated with goethitic iron oxide in the oxide zone. In the sulfide zone, native gold is associated with copper sulfide-sulfosalt mineralization. A genetic model for the Summitville deposit is based on recent models of modern geothermal systems, with which it shows similarities in alteration, ore mineralogy, zoning, and structural patterns.

Jan 1, 2013

By Innocent John Arinze, Chidubem Okwudiri Emedo

This contribution presents the first multi-scale geophysical investigation conducted in the Abakaliki and Obubra mining districts (AOMD), southeastern Nigeria, for the exploration of shallowly emplaced (< 50 m) massive sulfide and barite mineral deposits. Raw airborne magnetic data covering the AOMD was acquired and subjected to diverse enhancement routines to facilitate the identification of areas of subtle magnetic anomalies for subsequent ground truthing. The mineralization is mainly made up of galena, sphalerite, and barite. The contrasting physical properties between these minerals and their host rocks make resistivity, induced polarization (IP), spontaneous potential (SP), and magnetic methods ideal to study and delineate the mineralization and possibly locate the ore bodies. Wenner DC resistivity and IP data acquired along the same parallel traverses are inverted using Res2dinv to produce 2D tomography models of resistivity and chargeability. The resistivity and IP models were successful in delineating zones of sulfide and barite mineralization. The ground SP data collected along the same traverses as the resistivity and IP data were interpreted as line graphs. The 1D SP models show a number of central negative anomalies that could be related to sulfide mineralization. These anomalies show fair-to-good spatial continuity and are in close agreement with the result obtained in the resistivity and chargeability model. This study suggests the presence of exploitable mineral deposits in the AOMD and demonstrates the superior interpretative ability of combined geophysical methods over a single geophysical approach.

Oct 20, 2020

By A. Bhagavatula, M. Rezaee, M. J. Kiser, R. Q. Honaker

"A field study of the coal preparation plant fleet in the eastern United States was undertaken to determine if quantify of rare earth elements (REEs) present in the product streams are large enough to justify further concentration. Representative composite samples were taken from the clean product, coarse refuse, and fine refuse streams from 20 coal preparation plants. Each stream was then separated into various size and density classes and analyzed for ash and REE contents. The large database showed that coarse refuse contained the largest amount of REEs, although the ratio of heavy to light REEs was greater for the clean coal products. The concentration of REEs was also compared to that typically seen in the earth’s crust. This enrichment ratio ranged from approximately 1.5 to more than 4.0 as the ash content varied. The database also showed that a linear correlation existed between La and Ce for many REEs of interest, although there were several notable exceptions for some of the high-value REEs. INTRODUCTION Worldwide energy demand is expected to grow by as much as 37% by 2040 according to the International Energy Agency (2014). This growth, coupled with a decrease of the reliance on coal to generate energy, means that it is more important than ever for countries to secure the materials necessary to meet its energy projections. For the United States, the U.S. Energy Information Administration (EIA) predicts that total domestic electricity use will increase roughly 25%, from 3,836x109 kWh in 2013 to 4,797x109 kWh in 2040 (EIA, 2015). In the EIA’s reference case, coal’s contribution to electricity generation drops from 39% in 2013 to 34% in 2040. On the other hand, renewables share of electricity generation grows from 13% to 18% for the reference case. Compared to its current state, renewable energy electricity production is predicted to grow as little as 50% to as much as 121% over this time period, depending on the economic case being examined. This growth will largely be seen in the wind and solar sectors (EIA, 2015). The focus on viable renewable energy resources will be crucial to the future of fueling American growth. Many of the renewable energy technologies, such as wind turbines and photovoltaic films, rely on materials and supply chains outside of the United States. The lack of a reliable and low-cost domestic supply could pose a threat to the growth of the renewable energy markets in the United States. This potential vulnerability recently led the United States Department of Energy (DOE) to create a Critical Materials Strategy Report. In this report, 15 elements were identified as critical for the continued growth of the renewable energy market. Eight of these elements were rare earth elements (REEs). Five REEs (dysprosium, neodymium, terbium, yttrium and europium) were identified as highly critical and vulnerable to shortages (Bauer et al., 2012)."

Jan 1, 2016

By D. G. Chedgy

Environmental improvement efforts are focusing with increasing intensity on pollutants resulting from combustion. The high cost of removing these pollutants at the power station is well documented. Physical coal cleaning has always been and should remain the most economic method of reducing sulfur oxide emission from coal combustion. It is critical in the selection of preparation plant circuitry to consider capital and operating costs, as well as the level of sulfur reduction. This paper describes the technical criteria which must be used for efficient process selection and summarizes the cleaning systems available or in development.

Jan 1, 1990

By V. Russel Burkhart

One of the most difficult items to justify economically on any budget is a training program. The costs can easily be identified--primarily the cost of the program and the inconvenience and cost of filling in for the men taking the training by working other personnel extra hours at overtime rates. Operating efficiency, higher productivity, increased plant availability, development of confidence, improvement in morale and less absenteeism are only a few of the benefits which far exceed the costs. A good preparation plant training program can accomplish more in 5 weeks than can be accomplished in five years of on-the-lob operation. During recent years, coal preparation plants have become more sophisticated and complex as the specification for coal used by electric utilities in their power plants have required improvements in coal quality to adhere to air quality regulations and to improve boiler performance and reliability.

Jan 1, 1981

By L. A. Roe

The year 1867 marks the first year of commercial production of phosphate rock in the United States. South Carolina produced almost all of the domestic output of mineral phosphate until phosphate mining began in Florida in 1888. During the period 1868 to 1949 the total marketed production of domestic phosphate rock was about 186 million long tons of which 71.5 percent was produced in Florida, 18 percent in Tennessee and 7 percent in South Carolina (1). From 1949 through 1960, Florida phosphate rock production has ranged Prom 71 to 77 percent of the total domestic production. Since three-fourths of the domestic phosphate production is from the Florida field, and since most of the phosphate from the Tennessee and Western fields is not processed, but used directly as electric furnace burden, this paper will concern itself almost entirely with water requirements for mining and processing ore from Florida. Figure 1 summarizes phosphate rock production for Florida vs. total United States production over the period 1947-1960.

Jan 1, 1962

By J. W. Furlan

Due to the time consuming nature of froth testing in a laboratory environment, it is required, due to practical limitations, to develop a method of applying a single set of performance test data (Visintainer & Whitlock, 2012) obtained for a single froth pump at a given speed, to a range of froth pump speeds and sizes, % air contents, and liquid viscosities. Head, efficiency, and flow all vary as functions of both liquid viscosity and air content. As such, it is necessary to develop a technique which can be used to interpolate from existing test data in order to predict froth pump performance for pumps of various sizes running at variable speeds. Details of the technique developed in order to achieve this goal as well as the insights gained from analysis of the resulting regressions are discussed. Additionally, comparisons are made between the performance predictions of this test-derived method and those of the Hydraulic Institute Standard for the effects of liquid viscosity on centrifugal pump performance (ANSI/HI 9.6.7-2010).

Feb 27, 2013

By M. Ribeiro, P. So, P. Wong

Electrowinning is a process by which metals, such as copper or nickel, are recovered from aqueous electrolyte solutions resulting from the extraction of the metal ion from an acidic or basic leach solution. The electrolyte or “pregnant” solution is customarily forwarded to an electrowinning "tankhouse." In the tankhouse, the metal ions are deposited on cathode plates by electrodeposition and then recovered from the cathode plates. Other processes may be employed with other metals, such as nickel, zinc, among others, to produce an electrolyte from which their respective metals are obtained. During the electrowinning (electrodeposition) stage, elemental metal is plated out at the electrowinning cathode and oxygen evolves at an insoluble anode. The evolution of oxygen gas forms bubbles which entrain strong acid electrolyte, carrying it into the air above the electrowinning tank in the form of a fine mist or spray when the bubbles break. An acidic mist is generated above the electrolyte. This mist or spray then spreads throughout the electrowinning tankhouse. The acidic mist is corrosive and a health hazard and can cause extreme discomfort to the skin, eyes, and respiratory systems of tankhouse workers, especially during hot weather conditions. Polyfluoroalkyl based products (PFAS) have been widely applied as anti-misting agents in the electrowinning of metals in an acidic electrolyte. Functionalized PFAS compounds, however, have come under increased scrutiny by the EPA due to their impact on human health and the environment. There remains need for improved acid mist suppression agents for electrolysis and electrodeposition, particularly for products free of fluoroalkyl components.

Feb 1, 2023

The Putnam Coal Mine, at design capacity, will be the third largest underground bituminous coal mine in the world and will feature the world&apos;s longest single flight belt conveyor. Construction is now in process; initial mining will commence in early 1969 and design capacity will be reached in 1971. I&apos;m Jerry Workman, Assistant Mining Manager for the Coal Group of the Mining and Metals Division of Union Carbide Corporation, and I am acting as Project Manager for installation and start-up of the Putnam Mine. The Putnam Coal Mine reserves are located in south-central West Virginia and contain approximately 27,000 acres of prime Pittsburgh No. 8 coal; reserves are sufficient to support a 3.5 MM tons per year operation for over 30 years. The mine portal area is located some six miles inland from the Kanawha River. The river loading facility is located approximately 156 miles by way of river from the market.

Jan 1, 1968

By A. Noble

"A supply of sustainably sourced rare earth elements (REEs) is critical for several high-tech industries, renewable energy technologies, and defense applications. Recent studies have shown that REEs exist in coal and coal combustion byproducts at elevated concentrations and in quantities that could meet domestic demand. Despite these promising findings, declines in rare earth prices, volatile commodity markets, and challenging geo-metallurgical conditions have jeopardized this potentially valuable REE resource. While the dilute REE concentrations inherently necessitate low-cost separation technologies, the ultimately operating cost threshold for economic extraction must be based on commodity price projections and market demand. In this paper, the micro-pricing principle is used to develop a rigorous economic model assessing the inherent value of REEs in coal materials. This model is based upon basket pricing of individual elemental oxides, and elemental distributions of coal samples from various basins. These results may be used to assess the economic viability of potential REE concentration and refining technologies INTRODUCTION Recent efforts by US Department of Energy (DOE) and the National Energy Technology Laboratory (NETL) have suggested that rare earth elements (REEs) may exist in coal and coal byproducts at concentrations suitable for economic extraction and processing. While the knowledge of REE occurrence in coal material dates back over 50 years, recent supply restrictions and material criticality considerations have prompted a national interest to establish a sustainable domestic supply of REEs. REEs are not “rare” in the sense of crustal abundance; however, few natural processes lead to concentrated ore deposits. As a result, the elevated concentrations found in coal material may provide a potentially promising resource for these materials. While the term “rare earths” is often used to describe a singular concept, the 15 rare earth elements actually have varying and sometimes contrasting scarcity and cost profiles. Various authors have proposed classification systems to provide information on REE criticality (e.g. Seredin and Dai, 2012, Zhang et al., 2015). The most straightforward classification is provided on the basis of geochemistry with designations for “light”, “medium” and “heavy” rare earths. Light rare earths (those to the left of the periodic table: Ce, Pr, Nd, and Sm) tend to be more common and less valuable when compared to their medium (Eu, Gd, Tb, Dy, and Y) and heavy (Ho, Er, Tm, Yb, and Lu) counterparts. While light rare earths are often found in traditional ore deposits at economic concentrations, the heavier rare earths are almost exclusively found as ion-absorbed clays (Seredin and Dai, 2012)."

Jan 1, 2016