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By Shilpa S. Haramkar, Bhaskar N. Thorat, Sachin V. Jadhav

The filtration of phosphogypsum is a ubiquitous step in the manufacturing of phosphoric acid. It is highly desired to achieve the minimum concentration of P2O5 in the phosphogypsum cake. This work is aimed at addressing P2O5 losses in phosphogypsum (PG) along with the recovery of P2O5 from slurry by using constant pressure filtration at 1 bar pressure. Laboratory tests were carried out in the phosphoric acid production plant situated in Paradeep, India. Recycled water source near acid plant (i.e., pond water) was used for cake washing to reduce the burden on fresh water stock. The findings indicated that pressure filtration offered the most effective P2O5 recovery (nearly 93.48%). The moisture was reduced to 14–16%, and watersoluble P2O5 in the gypsum cake was found to be negligible. A narrow particle size distribution was observed, which offered effective filterability with average cake resistance of 2.38 × 1010 m/kg, indicating a moderately separable cake.

Aug 23, 2023

By Jodie Robertson, Isabel Barton, Cristian Caro

Prior to mining, all rocks contained in a mineral deposit must be placed in one of several categories known as ore types. Each ore type describes a different way that the rock will behave in processing. The ore type determines which process stream a particular mined unit will be sent to, sets expectations for process engineers and metallurgists, and forms the basis for recovery predictions and production estimates. At first, ore types are assigned mainly by geologists based on visible geological criteria (dominant ore mineralogy, estimated grade, rock type, alteration type). As metallurgical tests are carried out and process data accumulate, the resulting criteria may be factored into the ore typing process, typically as assays and recoverable metal using the relevant process(es). Other variables may also be incorporated into ore typing at operations if they are particularly important, such as grindability, preg-robbing, gangue reagent consumption, and the presence of especially deleterious minerals such as talc or smectite. The mine operation department may also redefine ore types and/or process destinations based on economic criteria. A “best” ore type is designated that (in theory) best describes how the rock will behave in processing. Codes representing this ore type are entered into the drill hole database, then interpreted on cross sections and level plans, and finally added to the block model. Ore types are iteratively reexamined and adjusted over the life of a project. Major difficulties in effective ore typing are (1) lack of communication between geologists and metallurgists, (2) the imprecision inherent in imposing clean categories on messy natural systems without discrete divisions, (3) the need for ore types to provide useful information for a wide range of processes, (4) difficulties in scaling up laboratory test results to mine production, and (5) conflict among geological, metallurgical, and economic criteria for ore typing.

Nov 8, 2023

By Quanjun Liu, Rongping Lin, Rongdong Deng

Arsenic contamination significantly affects the quality of copper concentrates, presenting challenges during smelting processes. Considering that covellite and enargite have similar surface properties, they are difficult to separate by flotation, resulting in copper concentrates with excessive levels of arsenic. To address this issue, this study systematically investigated the flotation separation of covellite and enargite in microflotation and bench-scale flotation tests using calcium lignosulfonate as a depressant, with the results indicating that calcium lignosulfonate can be used to separate covellite and enargite because it enables the separation of arsenic-bearing copper minerals into high- and low-arsenic (As 0.57%) copper concentrates. According to contact angle and adsorption tests, scanning electron microscopy–energy dispersive spectroscopy, and X-ray photoelectron spectroscopy, the differential adsorption of calcium lignosulfonate onto covellite and enargite is the primary reason for their distinct flotation behaviors in the presence of calcium lignosulfonate. The selective depressive effect of calcium lignosulfonate provides a novel approach for improving the flotation separation of arsenic-bearing minerals from copper sulfide minerals.

Feb 28, 2024

By Xie Junjie, Li Shina, Ma Ruixin, Min Changli, Yin Zichen, Li Kang, Shi Zhuonan

Cesium and rubidium were effectively separated by zinc ferrocyanide coprecipitation method, and the effect of precipitant addition amount on the separation of cesium and rubidium was studied. Under the conditions of Zn/Cs molar ratio of 0.45 and Zn/Fe molar ratio of 1, the precipitation rate of cesium is 84.01% and the separation factor of Cs/Rb is 164.65. The thermogravimetric curves of the sediment were measured, and the effects of roasting temperature, roasting time, and leaching liquid/ solid ratio on the extraction of cesium were studied. Almost all of the cesium was extracted under optimal conditions: roasting temperature of 600 °C, roasting time of 3 h, leaching temperature of 25 °C, leaching time of 0.5 h, and liquid/solid ratio of 5:1 mL/g. After the leaching process, the leach liquor with high concentration of cesium of 80.17 g/L was obtained. Finally, the leach liquor was further purified by solvent extraction, and the purity of the cesium chloride product reached 99.66%.

Mar 17, 2024

By Steven McCutcheon

As most of us have learned through prior and often frustrating experience, anyone proposing to construct a new or expanded mining-ore processing facility must first contend with a rather complex array of environmental laws and permitting regulations administered by a number of different Federal, State and local agencies. At our lost count, there were about 55 federal enactments affecting base and precious metals projects. Applicable State and local laws will usually increase that number significantly. The time and costs associated with complying with all these various regulatory programs usually constitutes one of the major areas of uncertainty in the development of a proposed project. There are many in the mining industry who firmly believe that these environmental regulation and permit programs necessarily causes significant delays and increased costs in the development of a project. This belief, unfortunately, is probably a result of a basic misunderstanding of how the environmental permitting and regulatory system actually works.

Jan 1, 1984

By S. A. Abetel Sabour

In this work, the block theory was applied to determine the safe limit of the angle of face slope at Limestone quarry of Assiut cement company in order to decrease the occurrence of dangerous potential key blocks. Four joint sets were observed and measured at the face. Computer program based on the vector analysis technique was developed to determine the removable block codes. Stereographic projection was also used in this work to determine the removable block codes and to calculate the maximum limit for the angle of dip of the free face, which was found to be 77°.

Jan 1, 1998

By Robert D. Harris

In 1958, the coal industry, through Bituminous Coal Research, Inc., and the electric utility industry, through the Edison Electric Institute and the Association of Edison Illuminating Companies, initiated a joint program to study coal pyrite and its removal as a means of lowering the sulfur content of steam coals. It was assumed that significant amounts of pyrite often remained in washed steam coal not because available systems for coal cleaning were inadequate, but because the pyrite was small and widely disseminated, During the first two years, samples of coal were examined petrographically to determine the size, association, and mode of occurrence of the pyrite in the raw coal and in the products of laboratory separation, Samples of coal were also pulverized in different equipment to determine how effectively pyrite was released by pulverization and if the mode of pulverization affected the liberation of pyrite. From these studies, the following tentative conclusions were made (1 ): 1. Much of the coal pyrite is within a 250-70 micron size range, and therefore is too small to be removed by conventional coal cleaning, but relatively large when compared to the size of coal as pulverized for combustion in large boilers. 2. The degree of pyrite liberation is mainly determined by the size of the product and not by the type of crusher. 3. For improved pyrite removal, the coal should be cleaned during or after pulverization at the power station.

Jan 1, 1965

By W. S. Hannan

History Leaching of sulfide ore was first attempted by the Phelps Dodge Corporation about 1900 at Bisbee, Arizona, when Dr. James Douglas conducted experiments in an attempt to apply the leaching techniques then in use at Rio Tinto, Spain. Although this initital attempt was unsuccessful, research work was continued which culminated in successful leaching operations at Tyrone, New Mexico, in 1917 and at Bisbee beginning in 1920. Leaching has continued intermittently since that date, with material from the Lavender Pit being leached today. The Lavender Pit Leach Dump Stripping for the Lavender Pit was started in 1951, with mining operations on stream in 1954 and continuing to the present. All material removed from the pit has been classified as waste, leach material, milling ore, or direct smelting ore, depending upon grade and degree of oxidation. Lavender Pit leach material has been stockpiled in a single dump, called No. 7 Dump. This dump covers an area of approximately 135 acres and average about 300 feet in height. The dump has been deposited over a period of 20 years by truck haulage and contains several layers, each of which has a permeable boulder layer at the bottom and a compacted layer at the top. Leaching of Lavender Pit material was started in 1956 and has proceeded simultaneously with dump construction. Former leach pond areas and haulage surfaces have been ripped with D-9 tractors before deposition of succeeding layers of ore.

Jan 1, 1972

By D. J. M. Grodzian

Polymorphic transformations taking place in grinding processes, of massicot to litharge in PbO system, and of y to a in Fe203 system, were re-investigated. Grinding was carried-on in a steeel rotation mill charged with WC balls, under inert atmosphere. The kinetics of transformation in PbO was established by means of quantitative X-ray diffraction analysis. The resulting data fit a modified logistic growth function up to about 75% of transformed volume fraction, when a mixture at steady-state equilibrium is formed. The reasoning for the use of a modified logistic function is discussed. A sigmoidal growth function can be used if resulting data fit also an empirical power relationship between transformed volume fraction and time. However, it lacks the significance expressed by a modified logistic function. Assuming, the loss in magnetism is directly related to the amount of transformation in Fe 203, a quantitative analysis was performed using a magnetic balance method. The results fit only the modified logistic growth function, and transformation proceeds almost to completion. A wide literature survey of the subject is given. Available data from literature is compared with the results of the present study, and is shown also to fit a modified logistic grown function, with surprisingly similar slpes in a linear plot, independently of the material. The instrumentation effect on kinetics parameters, and the establishment of equilibrium mixture values, are discussed.

Jan 1, 1975

By S. Grogan

Next year marks the tenth anniversary of the Surface Mining Control and Reclamation Act (SMCRA). As the U.S. coal industry scrambles to cope with serious economic difficulties, it is appropriate to examine some other difficulties that have their origin in certain provisions of that ten year old law, and that bear directly on the economic viability of surface coal mining in the west. This paper focuses briefly on three technical issues in the reclamation of surface coal mines in arid regions, and suggests that innovation can resolve these issues. The coal industry operates within a narrow legal context, defined in 1977. In enacting SMCRA, Congress listed among the purposes of the Act ?... to...strike a balance between protection of the environment, agricultural productivity and the Nation's need for coal as an essential source of energy." I maintain that such a balance has never been struck, particularly with regard to the reclamation of mines in the west. One reason is that when SMCRA was enacted its supporters were aware of uncertainties about the potential for successful reclamation of western surface mines. Over the intervening years, as a recent Congressional study report (OTA, 1986) points out, "...the risks these uncertainties may pose to the long term success of western reclamation have been reduced significantly." Unfortunately, SMCRA's enforcement agency, the Office of Surface Mining (OSM) has not yet recognized this fact, and the western coal industry is paying the price.

Jan 1, 1986

By Richard E. Beane

For several decades, the minerals industry has used leaching techniques to extract metals from rocks whose grade was too low to be treated profitably using conventional metallurgical techniques, and, as of 1972, about 15% of domestic copper production was derived using leaching methods (Beall 1). Increasing interest is currently being directed toward solution mining, particularly with respect to copper, for basically two reasons. In the first place, geological exploration has outlined several copper deposits of large tonnage and 1m', grade which are buried at sufficient depth to preclude open-pit mining which would make such mineral deposits ore deposits. Nevertheless, these occurrences provide significant potential if they could be treated by chemical leaching in situ. Secondly, the porphyry deposits of the western united States, which provide by far the largest percentage of domestic copper, do not terminate geometrically with sharp borders. These large disseminated bodies commonly decrease in grade laterally away from volumes of rock containing ore grade metallization, and the distinction between ore and waste is strictly economic. In order to extract ore grade material from the ground, a significant amount of rock containing sub-ore-grade copper must also be removed which, when placed on dumps, is amenable to solution mining. These two considerations clearly indicate the reasons for the growing interest in solution , leaching techniques--namely the ability to exploit deeply buried low grade deposits and the expansion of reserves in deposits currently under production.

Jan 1, 1977

By F. A. Renninger

The terms environment and environmental control, when used in today's context, generally imply to the average individual, something to do with pollution and pollution control. These latter terms, likewise, impart visions of fouled air and dirty water attributable largely to the industrial segment of American society. We have been conditioned, by various means, over the past ten years to equate environ¬mental control with pollution control. We have been trained to think of industrial environmental control programs as efforts conceived only to comply with one or more of the recently imposed pollution control regulations. Almost automatically we; approach consideration of environmental control with a degree of pessimism that is we assume that pollution prompted the control program. It is the purpose of this discussion to demonstrate that environmental control. at least as it exists and has existed within the crushed stone industry, involves far more than simply control or reduction of air and water pollution. It involves a dedication to the enhancement of each of the several "mini-environments" which together comprise the total world surrounding any given crushed stone operation. Environmental control, exercised properly, is an optimistic, constructive, forward-looking, enhancing type of activity. It is a function which has been, and should continue to be, willingly and expectantly undertaken by informed management personnel. In short, environmental control. is an activity from which both industry and society can and should benefit.

Jan 1, 1972

By J. Ludden

By Sims Some two years ago we began investigating low coke button bituminous coal for use at our Bound Brook, New Jersey plant as a replacement for anthracite. Since August, 1957 the plant has been operating continously on this coal with the exception of a new 200,000#/hr, cyclone boiler. This study was motivated not from our desire to conduct combustion research, but for the sole purpose of reducing our steam costs, The indications were that the economics were greatly in favor of the use of the bituminous coal. The attempts to reduce the costs have developed some knowledge that has enabled this program to succeed reasonably well as will be discussed later by Mr. Ludden. The production of steam size anthracite is dependent upon either the reclamation of old culm banks or the breakage in the production of the domestic sizes. The anthracite industry has not as yet been able to cut, its mining costs to the point where the production of steam sizes has become a profitable business. This has resulted in two basic problems: (1) A constantly rising price in an attempt to have those sizes carry their share of the cost and, (2) Periodic shortages of supply when the demand is good but the market price prohibits the mining of anthracite to produce those sizes only, These conditions have made the long range forecast appear as though the price would go even higher and/or the supply at times be critically short.

Jan 1, 1958

By W. G. Fischer

Trona ore at the Westvaco mine of FMC Corporation has been obtained by room- and-pillar methods since the mine began operation. The flat-lying, 10-foot bed of trona, Na2CO3 NaHCO3 2H2O, is covered by 1500 feet of weak shale and sandstone. Extraction of pillars on the retreat quite often throws large amounts of weight onto development workings. Weak shales in the roof and floor fail rapidly and the mine ribs slough to such an extent that mining often becomes very difficult. When this occurs efficiency goes down, costs go up, and the risk to men and machinery increases greatly. Difficult mining conditions in the early 60's forced a re-evaluation of all presently known mining techniques in bedded deposits. Many room-and-pillar mining plans' were compared with the system in use at that time, but none of them offered a better solution to the roof control problem. Longwall techniques were seriously considered, but machinery was not available that would cut the hard trona seam and still maintain the productivity obtained from room-and-pillar sections. Roof cones troy in the longwall methods appeared to be more satisfactory than that found in room-and--pillar techniques. It was therefore felt that a new technique using the longwall principle and based on rock mechanics should be tried rather than previously known pillaring methods.

Jan 1, 1966

By Donald J. Worth

When Eugene Bailey asked me to contribute to this session on "Canadian exploration - 1976", it took a little coaxing before he got me to agree. My immediate reaction was, what could i say about Canadian exploration that already had not been said a hundred times in the past few years; secondly, why include a banking person in such a discussion? Everyone knows banks only come into the picture after the discovery has been made and feasibility well established and validated. Rather than wrestle with these misgivings, I decided to take the easy way out and go on blind faith in Eugene - that is, he asked me so he must think that I could come up with some useful thoughts and at least touch upon some of the pros and cons of exploration in Canada. The object of the whole exploration exercise is to Find economic deposits, once they are found, one cannot really move them elsewhere to mine them. It follows, therefore, that we should really be speaking about the pros and cons of mining In Canada and my treatise will eventually lean in this direction. In any event and before getting down to the pros and cons, let us take a quick look at the history of mineral resource development in our country since the end of world war II. At that time, we were producing well under one billion dollars worth of mineral products including hydrocarbons.

Jan 1, 1976

By Byron R. Berger

Epithermal Ag-Au deposits form at low to moderate temperatures in near-surface environments. Historically, these deposits have been the source of high-grade ores. Increases in the market prices for gold and silver make lower-grade ores economically viable when available in large tonnages. Both the high-grade and bulk-tonnage ores are a consequence of the same processes, and general models of epithermal systems can be useful in the search for new precious-metal resources. A detailed study of deposits at Round Mountain, Nevada; Balei, Russia; Creede, Colorado; Guanajuato, Mexico; and Chanarcillo, Chile, indicates that the hydrodynamics of the fluid systems as determined by fracture geometries, the permeability, and composition of the host rocks are the key factors in the creation of both high-grade and bulk-tonnage epithermal deposits. End-member models that explain the range of observed deposit characteristics are: (1) the hot-springs deposition model; (2) the stacked-cell convection model (where mineral deposition occurs laterally along the interface of two partially separated fluid reservoirs); and, (3) the closed-cell convection model (where deposition occurs in vertical zones due to the relatively unimpeded vertical flow of hydrothermal fluids). Boiling and fluid mixing appear to be agents of precious-metal deposition with the self-sealing of the hydrothermal system being an important adjunct to boiling. Imaginative application of model concepts in exploration has led and can lead to the discovery of new high-grade and/or bulk-tonnage precious-metal deposits.

Jan 1, 1982

By E. W. Geist

This paper is presented from the viewpoint of the mill operator and maintenance supervisor. Its purpose is to highlight the things that have been accomplished by the mill designers to lighten the load for the maintenance superintendent and to reduce the overall costs for the plant operator. The complexity of plant design, the civil and structural engineering problems encountered when the satisfactory maintenance layout is accomplished are appreciated, and the writer is fully aware of the complexities of these problems. However, it is not the purpose of this particular paper to dwell upon these problems, nor to emphasize or de-emphasize the problems of the civil, mechanical and electrical engineers. It is simply that the paper will attempt to review what these people have accomplished in spite of the many technical problems. This paper then is prepared with the operator and maintenance people?s viewpoint. What is their definition of design for maintenance? It is the writer's interpretation that the various design concepts which mean improved maintenance are such items as (I) maintenance areas, (2) laydown space for maintenance materials in specific maintenance jobs, (3) the inclusion of bridge cranes in the plant and specific design of the craneways to accomplish flexibilities for the cranes, and (4) the location of the piece of equipment to allow maintenance people to work around the equipment - - - this specifically includes the orientation of the particular piece of equipment.

Jan 1, 1967

By R. Sellaro

It has long been understood that extended occupational exposures to respirable mine dusts can lead to chronic lung disease. In underground coal mines, coal workers pneumoconiosis (CWP) and silicosis are major concerns. While there have been many studies aimed at understanding total dust concentrations and silica content associated with different mining conditions (e.g., locations/occupations within a mine, cutting methods, geologic strata), little research has been completed to more comprehensively characterize respirable dust (i.e., by distributions of particle composition, size or shape). For such analysis, scanning electron microscopy with energy dispersive X-ray (SEM-EDX) may represent a powerful tool. This article is a preliminary investigation of SEM-EDX to characterize respirable dust from an underground coal mine in Central Appalachia. Samples were collected from various locations in the study mine, and individual dust particles were identified and classified by mineral type. A continuous personal dust monitor was also used to estimate respirable dust concentrations during sampling. This data was compared to particle densities observed under the SEM. Dust is generally defined as small, solid particles with an effective diameter between 1 and 100 µm. In underground coal mines, dust is produced by a variety of activities such as coal and rock cutting, materials handling, haulage and from a variety of materials. While the coal itself is primarily made up of organic carbon, it is estimated that as much as 60 percent of coal mine dust consists of mineral matter, including clays, metal oxides and sulfides, carbonates, quartz, phosphates and heavy minerals (WHO, 1997). Mineral matter may be ingrained in the coal seam or associated with adjacent or interlying strata, and may also be contributed by specific activities such as rock dusting. When dust is generated or made airborne, suspended particles tend to settle slowly with gravitational forces, but can remain airborne for extended periods of time depending on environmental conditions such as air velocity (Courtney et al., 1986) and particle properties such as size (ISO, 1995; WHO, 1999). Thus, miners working underground are routinely subject to occupational dust exposures ? with highly variable characteristics between and even within mines.

By H. X. Li, A. Correa, M. M. Zhang, W. Xuan, M. Andrade

"With increasing demand for steel and depletion of high-grade iron ore deposits, more research efforts are being directed toward extending the life of existing ore reserves and developing technology to treat low-grade iron ore resources. Among all the reported technologies, biotechnologies in mineral processing – specifically bioleaching and microbially induced flotation – have emerged to be considered as low-cost, environmentally friendly potential alternatives to many of the current mineral processing techniques. This paper provides a comprehensive review of current research on the use of microorganisms for iron ore beneficiation and, further, discusses the applicability of bioleaching, bioflotation and bioflocculation for the beneficiation of low-grade iron ores.IntroductionIncreasing global demand for raw materials has led to diminishing resources of high-grade iron ore. As a result, the mining and utilization of low-grade hematite, limonite, specularite, siderite and goethite ores have attracted more and more attention. However, these types of iron ores are of complex paragenesis and fine disseminated grain size, and often contaminated by phosphorus in the form of solid solution. The distribution of phosphorus throughout the iron mineral crystals prevents the effective use of physical separation techniques, and these complex ores are at present largely untapped due to a lack of cost-effective and efficient processing methods. Chemical leaching and roasting-magnetic separation approaches have been mainly tested only on the laboratory scale and are all either cost prohibitive or ineffective when used on low-grade complex iron ores."

Jan 1, 2015

By C. Ottergren

A process does not have higher capacity than what can pass through its bottleneck. Acknowledging this, and with the goal to optimize production at a minimum investment, one can use existing equipment, modify the process flow and make a few strategic capital investments. Automatic setting regulation is a technology that allows balanced crusher performance matching minute changes in feed material characteristics. The system makes it possible to utilize the crushers fully at all times. It also continuously and completely compensates for manganese liner wear.

Jan 1, 1999