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By Hamid Mazouz, Mohammed Hakkar, Rim Jouraiphy, Fatima Ezzahra Arhouni, Ahmed Mahrou, Aziz Boukhair, Mohammed Fahad

The wet process is the most commonly used worldwide for phosphoric acid (PA) production, in which phosphate rock (PR) is reacted with strong acid mainly sulfuric acid. This work aims on studying the rare earth elements (REEs) distribution during the production of phosphoric acid using different qualities of phosphate through various industrial technologies. At the onset of this work, the process started with 12 samples of PR, PA, and phosphogypsum (PG) being taken simultaneously from two different Moroccan basins (Ouled Abdoun mine represented by K09 and Gantour mine depicted by G10, G20, BG) and various production lines at two processing platforms (Jorf Lasfar and Safi). Afterward, collected samples were prepared and analyzed for REE characterization using an inductively coupled plasma mass spectrometry (ICP-MS). Based on the analysis results, a transfer factor ( TFX) was introduced with the aim of gauging the REE distribution between PA and PG. The results showed that the total concentration of REEs in different phosphate qualities ranged from 411 to 631 ppm; the major part of this concentration was attributed to the four elements: Y, La, Ce, and Nd which constitute more than 77%. The REE distribution between PA and PG depends on neither the phosphate quality nor the industrial technology used since that the distribution results showed that 55 up to 66% of the initial REEs in phosphate rock ended up in the PG. The behavior of each REE was common except for the element scandium, which transferred mainly to the phosphoric acid.

Nov 3, 2021

By S. A. Montague

In spite of the many new insulating materials, both synthetic and manufactured, that have been put on the market since the end of World War II, and notwithstanding the many millions of dollars applied to the development of synthetic mica, natural block mica1 is still a most indispensable insulator in various electronic components. It will remain so, barring some spectacular break-through in research that might provide a substitute fully acceptable as a replacement for mica in all of its superior properties. But this is not to say the future for mica is assured, or free from serious problems. Technological advances have created problems requiring a solution to be found if future requirements are to be filled.

Jan 1, 1962

By Peter G. Sechiari

The Rio Tinto-Zinc Corporation Limited (RTZ), through it exploration company Riofinex, commenced exploration for bauxite in the Amazonia region of Brazil during 1970. Following' encouraging indications, exploration licences were taken out and an exploration programme was initiated In February 1975, a preliminary 'feasibility report indicated that a project, based on the Miltonia plateau located close to the town of Paragominas in the State of Para, was viable and that barging might offer an economic solution to getting the product to an ocean-going port. A, decision was taken in April 1975 to proceed with a full feasibility study. In the latter stages of the study, an engineering consortium of Mendes Junior and Bechtel do Brasil was employed to review, and modify if necessary, the concepts that RTZ had developed for the project's operation. With these concepts agreed, the consortium was requested to make capital and operating cost estimates, and these became available during February 1978. The deposit is being developed by a Brazilian company Mineracao Vera Cruz S.A. (MVC) in which the present share-holding is owned 64 percent by RTZ and 36 percent by Companhia Vale do Rio Doce (CVRD). RTZ is a British based international group of mining and industrial companies with interests in almost every major metal and fuel. CVRD is a Brazilian mining company, 85 percent owned by the Brazilian Government, with a major interest in iron ore and also other non-ferrous metals. It is intended, in due course, that the company will become majority owned by Brazilian interests.

Jan 1, 1979

By R. D. Miller, L. Schulte, J. Davenport, D. W. Steeples

Shallow seismic reflection methods were successfully used to delineate the subsurface extent of roof failure associated with the dissolution mining of a 120-m (400 ft) deep and 60-m (200ft) thick salt bed in central Kansas. Surface subsidence at North American Salt's Hutchinson, KS, salt-dissolution well field represents a potential risk to surface structures and transportation facilities. Three intersecting common depth point (CDP) seismic reflection profiles, targeting the subsurface around an actively subsiding sinkhole, possess sufficient resolution to delineate the horizontal and vertical extent of subsurface rock failure associated with the subsidence. The three seismic profiles showed a disturbed subsurface area 90 to 105 m-diam (300 to 350 ft-diam) at a depth of between 60 to 75 m (200 ft and 250 ft). Confirmation drilling verified the interpretation of the seismic data. The seismic reflection method has the potential to resolve disturbed subsurface areas greater than 23 m-diam (75 ft-diam) at this site.

Jan 1, 1994

By D. M. Thayer

Dry magnetic separation of feebly magnetic minerals and wet magnetic separators suitable for highly magnetic minerals have been commercially utilized for a number of years. The beneficiation of magnetic taconite ores by conventional, low intensity magnetic separators in combination with flotation is well established technology (1). However, over the past decade much effort has been expended in developing techniques for the upgrading of feebly magnetic oxidized iron ores (2,5). Such research and development have been stimulated by the limitations of the above-mentioned techniques in application to ores containing fine material; for example, ores requiring fine grinding for liberation or slime-forming ores such as the oxidized taconites or semi-taconites. Wet separation has allowed the reduction of the minim particle size that can be effectively treated from that allowable for high intensity dry magnetic separation. Consequently, the development of high intensity wet magnetic separation methods has received much attention in the search for an effective method to treat the weakly magnetic minerals. Recently Lawver and Hopstock (5) have provided an excellent review of the state of know- ledge of this technology. In addition, a valuable compendium of available laboratory and commercial devices is included. Nonetheless, the feasibility of the use of high intensity magnetic separation in a particular application is largly empirical in nature and requires experimentation to chazacterize the response of a particular ore. The purpose of this paper is to assess the incorporation of high intensity magnetic separation for the beneficiation of a non- sliming specular Michigan hematite. Particular attention is focused on the existence of a lower limit of particle size that can be treated effectively and is inherent in the use of these techniques. Additionally, a rationalization of various models presented in the literature is attempted.

Jan 1, 1979

By P. Soros

Rich iron ore deposits were discovered during the 1960's in the mountain range of Serra dos Carajas, State of Para, Brazil, near the headwaters of the Tocantins River some 400 miles southwest from the state capital of Belem. (See Fig. 1 and 2). The key to the successful exploitation of this deposit was the development of an efficient an economical transportation system. The rugged terrain, and the dense tropical vegetation of the Amazonian jungle and the irregular coastline with its high tidal range presented severe obstacles to the planning and building of such system. Starting in 1972 extensive surveys and studies were carried out by Soros Associates on behalf of CVRD to determine the optimum way of transporting the ore from the mine site to the markets, most of which are located overseas. Overland transportation to the coast, loading into seagoing vessels and the ocean voyage to the ports of destination was treated as an integrated system in these studies.

Jan 1, 1986

By C. A. Rowland

When studying the feasibility of using autogenous or semi-autogenous grinding, operating and engineering companies frequently request assistance from the mill manufacturers in three areas - 1. Recommendations for studying the suitability of autogenous or semi-autogenous grinding for the specific ore. 2. Mill sizing, to accomplish required grind. 3. Recommendations on mill design and operation. Rod mills and ball mills are selected by the use of bench scale standard grindability tests and established calculation procedures, of which the most frequently used are the Bond Grindability tests and the Bond Work Index equation(1). The accuracy of these have been reviewed by C. A. Rowland in his papers, showing the correlation of work indices calculated from plant operating data and laboratory grindability tests(2)(3). The selection of autogenous and semi-autogenous primary mills has not reached the stage where mill size selection can be made from bench scale tests. Considerably more extensive testing will be necessary than required for selecting rod mills and ball mills.

Jan 1, 1974

By D. A. Peterson

A research program is currently in progress at the University of British Columbia to determine the potential of composite cable bolt reinforcement in Canadian mines. Several prototypes of glass fibre cable bolts have been tested. Their evaluation consisted of lab testing at the University of British Columbia, United States Bureau of Mines (Spokane) and trial installations at Detour Lake, Winston Lake, and Myra Falls Mines. A market analysis of cable bolts within the Canadian mining industry has been completed. Fibre reinforced polymer composites have a high potential as cable bolt reinforcement in mining applications. They prove to be a viable alternative to steel cable bolting.

Jan 1, 1993

By R. R. Odman

The Malmberget Division of LKAB is located 70 km north of the arctic circle and has about 2000 employees. The dominating products are sinter feed concentrate and pellets. A general flow sheet for the operation is shown in Figure 1. About 20 percent of the ore body consists of hematite, which is mined separately and processed into sinter feed concentrate. That pert of the ore consisting of magnetite passes through a dry cobbing plant. The robbing process includes crushing, screening and dry magnetic separation. The entire cobbing product is used as feed for the wet concentrator. After rod mill grinding and magnetic separation the concentrated slurry is classified. The coarse fraction (+200 mesh) becomes sinter feed concentrate and the slime fraction after further ball mill grinding and magnetic separation, becomes pelletizing feed. A small quantity of the magnetite ore is processed into special iron-rich products in the the wet concentrator. Two types of pelletizing plant are used, shaft furnace and straight grate. This paper will deal only with experience gained at the straight grate plant.

Jan 1, 1979

By Charlotte Abena Benyarku, Albert Buabeng, Eric Stemn

The abstract highlights the increasing use of mobile equipment in mining and its contribution to accidents. The research analyzes injury narratives from Ghanaian surface gold mines to understand the involvement of mobile mining equipment in injuries and explore the use of injury narrative data as a human factors tool. The study identified priority human factor issues, such as operating mobile mining equipment, part removal/installation, and the operator's cabin. The use of Sankey diagrams for multivariable analysis effectively identified specific operator-centered issues that warrant further investigation for improved safety interventions.

Mar 29, 2022

By A. W. Khair

Surface subsidence is a phenomenon mainly associated with longwall mining, although it can also occur if the coal pillar left to protect the surface deteriorates with time and results in the collapse of the room and pillar system. A method has been developed that utilizes physical mine models and laser holographic interferometry. This method is capable of measuring displacements as small as 5 micro- inches by means of generating displacement contours on a surface, even that of granular materials. Analysis of subsidence in room and pillar mining using models of various extraction ratios ad overburden depths along with two different types of overburden model material (sand and gelatin) has been made. The sand represented the extreme brittle conditions of geologic material while the gelatin represented visco-elastic behavior of geologic material. This paper deals with the analysis of data which has been gathered up to date, and mainly associated with the use of sand as an overburden model material. The analysis included the effect of variation of geometric parameters on surface subsidence. Among these parameters are: variation in seam depth and thickness, surface and seam inclination, and extraction ratio.

Jan 1, 1984

By Syd Peng, W. B. Guo, F. Du, L. Yang, J. Yw. Cheng

The annual ICGCM China was initiated in 2014. Up to 2023, ICGCM China has been held 9 times. In the 9 conferences during the past 10 years, about 559 papers in 17 topical areas were presented and attendance ranged from 200+ to 400+ each conference. The 42nd ICGCM China was held in Xiangtan, Hunan, China, 10/20–10/22/2023. There were 86 papers presented in 26 topical areas. In addition, an MS and PhD Research Forum was held concurrently with 36 papers presented by MS and PhD candidates in mining engineering from 8 schools. The conference plays an important role in cultivating advanced degree student talents. In this paper, all 559 papers reviewed previously were summarized. In addition, the 42nd ICGCM China is used to illustrate the current and future development trends of coal mine ground control in China. It summarizes the 122 papers (including 36 MS and PhD forum papers) grouping into, and in terms of, 26 topical areas. In addition, its unique and innovative subject areas, short summary of developments as well as conference strengths and shortcomings will also be presented.

Jun 25, 2024

By Earl Cook

A high-energy economy based on fossil fuels is in fundamental conflict with an ideal of clean air, clean water, undisturbed scenery, and maintenance of fragile ecosystems. There is an inevitable trade-off between the material standard of living of a modern society and the conservation of its environment. During the past four years, some of the costs of environmental protection have been internalized in the energy-flow system of the United States. The cost of bituminous coal and fuel oil usable under new air-quality standards has doubled or more. The cost of mining coal underground has risen because of a 20-30 percent reduction in productivity resulting from new environmental health and safety legislation; the economic impact of proposed surface-mine regulation may be equally severe. The cost of producing electric power has been rising at a 12 percent annual rate because of environmental costs, and would be climbing still more steeply were it not for the continued forced subsidy of natural-gas consumers by natural-gas producers. The efficiency of the automobile, already a monument to the triumph of self- indulgence over economy, is being further decreased by addition of anti-pollution devices. Part of the recent sharp rise in agricultural costs stems from the fact that five energy units of fossil fuel go into U.S. agriculture for every energy unit of raw food that leaves the farm; further large injections of fossil-fuel energy occur in the transport, processing, and refrigeration of farm products.

Jan 1, 1974

By Hendri Silaen, Ishak Degei, Nicoll Soumilena, Arwin Edijanto, Avesiena Primadiansyah

PT Freeport Indonesia’s Deep Mill Level Zone (DMLZ) is one of three operating cave mines at the Grasberg mine complex. The DMLZ is situated in the East Ertsberg Skarn System (EESS). It is set 500 m below the operating DOZ mine and located approximately 1,500 m below the surface, making it one of the world’s deepest panel caving operations. Initial undercutting of the DMLZ commenced in the second half of 2015 and has expanded to more than 120,000 m2. High pre-mining stresses and the changes associated with caving, combined with a strong and brittle rock mass, led to significant seismicity and rock bursting. Stress and seismic management are the main challenges for the operation and have evolved significantly from initial undercutting to the present. Considerable amounts of empirical data associated with ground response have been collected, evaluated and combined with historical lessons learned from the Intermediate Ore Zone (IOZ) and Deep Ore Zone (DOZ) mines, which are located within the EESS. This has provided an improved understanding of how the various geological, geotechnical and mine design criteria relate to one another. Additionally, the information has allowed for the development and implementation of improved strategies for stress and seismic management in the DMLZ. This paper describes how these learnings have driven changes in mine geometry, layout, and support systems. Through comprehensive monitoring and detailed inspections, positive changes have been seen in the ground response, leading to an increase in footprint reliability and accelerated cave growth. The paper summarizes the key learnings at the DMLZ regarding stress and seismic management as well as the positive improvements towards sustained and safe caving operations in the DMLZ.

Apr 26, 2022

By N. W. Johnson

The behavior of non-sulphide gangue in chaloopyrite flotation circuits has been investigated. Plant and laboratory tests were carried out on five different ores, and linear relationships were found to exist between the rates of recovery of water and free nonsulphide gangue in the concentrates although there was evidence from pilot plant tests that these were linear approximations to parabolic curves over the limited regions which were observed. There was evidence that the free non-sulphide gangue enters the concentrate by hydraulic classification and a classification function has been proposed to define this behavior. This function is suitable for inclusion in a mathematical model of the process.

Jan 1, 1972

By Henry N. McCarl

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Jan 1, 1966

By O. Ozcan

Oleic acid has been almost invariably used in the flotation of siliceous fluorite ores. The performance of oleic acid, however, deteriorates with carbonaceous fluorite ores. Oleoyl sarcosine developed recently has been found to produce results superior over oleic acid with ores containing high calcite contents. While the mechanism of oleate adsorption is usually considered as chemisorption involving calcium oleate formation on both calcite and fluorite, no mechanism has been so far proposed to explain the adsorption mechanism of oleoyl sarcosine. In this study, the selectivity of oleoyl sarcosine, as inferred from flotation, zeta potential and infrared measurements, is ascribed to the interaction of fluorine ion to the nitrogen via hydrogen bonding.

Jan 1, 1994

By A. S. Hall

Significant pyrite often does not dissolve in the Sobek (1978) nitric acid extraction; therefore, the standard conservative approach is to estimate pyrite using sulfur present in the sum of the nitric acid and residual sulfur fractions. Alunite, when present, appears as residual sulfur. Because alunite does not generate acidic effluents, overestimation of AGP can occur if all residual sulfur is assumed to be undigested pyrite. Evaluation of 16 samples from the Florida Canyon Mine revealed that petrographic examination coupled with a modification of the Sobek method to include a 6 hour hot (250°F) 'nitric acid extraction resulted in a more accurate estimation of AGP.

Jan 1, 1999

By R. E. Pennington

My subject this morning is coal liquefaction technology. Actually, coal liquefaction involves a number of technologies in a very complex system. The first slide shows the major components of such a system with arrows to indicate appropriate flows. The components are the facilities for coal feed preparation and handling; the coal hydrogenation or base liquefaction section; facilities for product separation and recovery, and in addition, facilities for the production of hydrogen from coal-based sources. A very rough break- out of the investments involved in these areas is given at the bottom of the slide. Investment is spread about equally among the three areas of operations Another way of looking at it is that the investments in what might be called support facilities are of the same magnitude as the base investment in the hydrogen facilities. Therefore, it is appropriate in a discussion of coal liquefaction technology to treat it as a system composed of a number of technologies. The next slide lists the various functions in the feed preparation section along with an indication of technology status. Storage, crushing, grinding, drying of coal all have been in commercial practice for a number of years. The slurrying and pumping of coal at least in water slurries, is practiced commercially also. The heating of coal slurries in oil to high temperatures under pressure is not in commercial practice and development and testing is going on by a number of people in this area. Some rather complex phenomena occur when coal oil slurries are heated to high temperatures.

Jan 1, 1975

By Deepak Malhotra, Linda Battich

INTRODUCTION Mineral processing plants generally operate efficiently within the technical, economic and management constraints applied to them. They have no choice, because the dynamic and competitive nature of the mineral business dictates that survival and/or prosperity of the company depends on being a low cost producer. Progressive mineral companies realize that market downturns will occur, and they must continuously strive for lower unit production costs rather than be satisfied with the status quo. Mineral companies generally tend to reduce costs during market downturns. This short-term solution is achieved by high grading of ores, and cut-backs In waste stripping, exploration, and capital expenditures.(1) However, to remain a low-cost producer in the long term, companies must enhance revenue and reduce cost simultaneously. This Involves continuous evaluation of technologies and reagents, periodic audits to locate revenue losses; and gathering and analyzing statistical plant data to clearly understand the Impact of process variables on efficiency. Mineral companies are caught in a Catch-22. They need resources to accomplish the objectives outlined above. Most mill stuffs have been cut to the minimum level necessary to maintain production. Resources such as time, manpower and money are scarce, and mill metallurglsts struggle to use these resources productively. Is your flotation plant optimized? History Indicates that successful operations constantly tune the flotation circuits to Improve metallurgy or reduce cost. This Is the essence of evolutionary change In mineral processing operations. A plant auditing approach can play a key role in assisting the process engineers to achieve the overall objective of enhancing metallurgy and reducing cost with limited resources through evolutionary improvements. FLOTATION SYSTEM The flotation process is the most widely wed concentration process In the world today. The number of variables that can affect the flotation results Is very large, maybe over 100. These variables can be divided Into three main groups: (2) (1) ore and mineral properties; (2) reagent treatment; and (3) flotation machine characteristics. Some of these variables can be controlled while others have to be accepted. Recently, Investigators (3,4) have attempted to describe the flotation process as an engineering system which includes chemistry, equipment and operating variables. Though some of the variables are Independent, most are co-dependent. thus making it difficult to develop simple cause and effect relationships. For example, it is easy to understand the effect of reagent change on recovery and grade In the rougher circuit, but very difficult to quantify Its impact on filtration downstream. Plant audits on a periodic basis are necessary to develop an understanding of the Interactive nature of the system. Auditing provides comparisons of plant operating performance before and after variable changes. OVERVIEW OF PLANT AUDITING An audit Is a formal, thorough and periodic examination of a system. There are various types of audits (i.e., geological, environmental, metallurgical. economic, etc.), and each serves a different purpose. (5) The discussion here is related to plant and/or metallurgical audits. Neale and Flintoff note that two key factors governing changes In an operation are: (1) the opportunity must be recognized; and (2) the justification for change must exist. (6) Both factors emphasize the critical role of successful plant auditing. Without plant audits. many opportunities for improvement must go unrecognized. On the other hand, when a situation ripe for improvement Is recognized. the hard data from a plant audit can reveal the expected impact of an operating change.

Jan 1, 1993