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By V. A. Mironenko

The combined study of ground water regime and rock deformations has resulted in the theoretical substantiation of the common principles for analysis of the hydrodynamic and geomechanical processes Within the scope of unique scientific direction -hydrogeomechanics (Mironenko and Shestakov, 1974). The hydrogeomechanical models are widely used now for the analysis and forecasting the extremely important processes connected with the safe and efficient mining operations, as well as with the protection of geological medium. Among these processes are: -deformations of the open-pit slopes and spoil dumps; -consolidation of rocks due to the ground-water pressure drop; -water-end-rock material inrush into mine workings caused by deformations of the undermined rock mass; -geodynamical processes due to the changes in ground water regime; -artificial hydrofracturing in rocks; -transformations of clay linings under the tailing ponds and other technical water basins.

Jan 1, 1990

By Kenneth N. Weaver

Introduction and Historical Background State Geological Surveys have been deeply involved in industrial minerals from their inception beginning in the first half of the 19th Century. To Massachusetts belongs the credit of having carried out the first Geological survey under state auspices on the Western Hemisphere. One of the causes leading up to this survey was. Governor Lincoln's message to the legislature of May 29, 1830, from which I quote in part: "Much knowledge of the natural history of the country would thus be gained (from a geological survey), and especially the presence of valuable ores, with the localities and extent of quarries and of coal and lime formations, objects of inquiry so essential to internal improvements and the advancement of domestic prosperity, would be discovered.". Similar phraseology is present in practically all of the initial organic acts creating the first State Surveys. High on the list of priorities for these embryo surveys was an inventory of the mineral resources of the State with particular emphasis on the industrial minerals. Prom these early beginnings, the state surveys have developed a great wealth of geological data either directly or indirectly relating to the development of mineral resources. One can gain some conception of the effort that state surveys today place on industrial minerals studies by noting the projects in which they are engaged as reported in the State Geologists Journal. In 1970, for example, approximately

Jan 1, 1972

By Goran Mathisson

In several investigations the correlation has been studied between the fuel consumption and the reducibility of the charged material in the zone of indirect reduction in the blast furnace (1, 2, 3, 4, 5). It has been found that increased reducibility allows greater gas utilization which accordingly lowers the fuel consumption. In direct reduction units this relation has not yet been fully established partly owing to the lack of accurate test methods and experience with different materials as regards reducibility. However, since the production rate in a direct reduction unit is closely related to the time required to reach high degrees of reduction, the reducibility must be regarded as one of the most important properties of the material.

Jan 1, 1979

By H. Walqui

The Empire concentrator was built in four stages, with the latest stage accounting for 50% of the overall plant capacity. Over the past 5 years, the average throughput of the three grinding lines has decreased by 50 LTPH (15%) without significant changes in ore characteristics and despite the addition of secondary grinding capacity to supplement the existing pebble mills that are the constraint of the grinding circuit. This paper discusses the different areas under study that are aimed at optimizing grinding circuit utilization which includes improving system logic, pebble crushing operation and pebble mills operation.

Jan 1, 2009

By Liming Yuan, Wei Tang, RICHARD THOMAS, JOHN SOLES

Lithium-ion battery pack fires pose great hazards to the safety and health of miners. A detailed experimental study has been conducted at the National Institute for Occupational Safety and Health (NIOSH) Pittsburgh Mining Research Division (PMRD) to investigate the effectiveness of different fire suppression systems on Li-ion battery pack fire extinguishment. Tests were conducted in a well-ventilated container. Two sizes of battery packs (12 V, 24 V) were heated by heater strips to trigger thermal runaway and fire. Water mist with different flow rates, ABC powder, type D dry chemical, and water mist with F500 additives were used as the fire suppression agents. Multiple thermocouples were installed on the battery packs to measure the temperature evolution during the tests. The results indicated that the water mist with F500 additives is the most effective suppressant among the agents tested. Dry chemicals, however, do quench the fire for a moment, but cannot prevent re-ignition of the battery since they do not provide enough cooling. The findings of this paper can be used to develop safer battery fire suppression techniques in mining environments.

May 4, 2023

By D. T. McMurray

INTRODUCTION Shabanie mine, situated some 180 km east of Bula¬wayo, has been a producer of chrysotile asbestos for more than 50 years. The ore bodies occur in serpentinized dunite, which overlies talc-carbonate schist. A zone of relatively competent rock of varying thickness occurs between the schist and the ore bodies, which are gen¬erally less competent. The hanging wall of the ore bodies is economic, and the hanging-wall serpentine carries a variable subeconomic amount of fiber. It is important to note that, in general, the ore body competence is less than that of the foot and hanging-wall formations. Historical After surface operations ceased, cut-and-fill stoping was used to win ore from underground; this was success¬ful until the increasingly stoped-out area caused insta¬bility in the stope pillars and back. Consequently, dur¬ing the early 1950s, a gradual change to cave-mining methods was made, the ore being won by hand lashing in drawpoints, situated in the basement of the stope blocks, and passed through orepasses under gravity to the haulage level some 13 m below. About this time, interest was focused on the sub¬level caving method in use in Swedish iron ore mines: it was felt that it might be applied economically to the Shabanie ore bodies. Accordingly, in 1958, an experi¬mental stope block was laid out in which sublevel inter¬vals and extraction tunnel spacing were 9 m. The tun¬nels (ring drilling drives) were oriented on strike-in contrast to the Swedish system, in which crosscuts that retreat from hanging to footwall are used. The advantages of the method were quickly appre¬ciated by the operating personnel and, despite the in¬evitable teething troubles pertaining to the introduction of any new mining method, it was not long before sub¬level caving was providing a high proportion of the mill feed. The disadvantages also became apparent at an early stage, however, and, from that time to the present, continuing modifications have been made to mining lay¬outs in an effort to improve ore recovery. GENERAL DESCRIPTION OF METHOD The mine is served by a vertical hoisting shaft, in which two skips, a man cage and a service cage, provide adequate capacity for production requirements. The rock hoist is a Ward Leonard control hoist, in which two electric motors drive a common gearbox. The man winder is driven by an a-c motor. Several auxiliary shafts provide secondary egress and intake and return ventilation. Main haulage levels are above (Fig. I a and b). Blasthole fan patterns are drilled by drifters of 100 mm bore, drilling 41-mm holes; when a sufficient strike length has been drilled, a slot is cut in the upper¬most sublevel and the rings are broken into the slot. Initially, a limited tonnage is drawn, since it is essential to ensure that the hanging wall caves behind the retreat¬ing stope face. Once this has been established, maxi¬mum tonnage can be drawn, as described later in this chapter, under the heading "Draw Control." The broken rock is loaded by 0.14 and 0.20-m3 load¬ers into cocopans (rocker-dumping type of tipping truck), which are hand trammed to orepasses, discharg¬ing on the haulage where 11-t electric trolley locomo¬tives haul 3.95-m3 Granby cars to the main shaft bins. As is evident from Fig. 1, the layout is simple, the block is brought rapidly into production, there is a high degree of selectivity and flexibility, and the result is a low-cost high-productivity mining method. DEVELOPMENT Main haulages are developed at 3.2 x 3.2 m, and once the service winze connections have been completed the development of the sublevels is undertaken. The footwall drives are cut first, to obtain access to the block. These ends are of the standard section, 2.4 x 2.8 m, and from them crosscuts at intervals of 70 m are driven through the ore body to the hanging wall. These crosscuts are used to supplement the geo¬logical information previously obtained from diamond core drilling, and they provide additional and more de¬tailed data on fiber percentages and lengths, structural features, and other relevant criteria which are used to build up the geological assessment of the area and to classify it in terms of the geomechanics rock classification (Laubscher and Taylor, 1977). The crosscuts also allow the necessary orepasses to be sited conveniently so that tramming distances from the loading points are not excessive. Development Drilling Once the skeleton development has been completed, the extraction headings are developed at 2.4 x 2.4 m as shown in Fig. 1. Standard development practice is to use crews of a machine operator and his helper, equipped with air-leg mounted jackhammers, to drill rounds of 1.8 m with integral tungsten carbide tipped drill steel. The round drilled is a normal drag round, as shown in Fig. 2, but considerable attention is paid to the drilling of the perimeter holes to use effectively the

Jan 1, 1982

By C. Allen, H. Zhang, L. Falk

Shock loss occurs when there is a change in the area of a drift or airflow direction. These shock losses accumulate throughout the ventilation system and will increase the mine resistance as underground development deepens or becomes more complex. Hence, shock losses should be carefully considered when establishing the resistance through a series of branches as they can be a significant contributor to the estimated mine resistance. Using computer software to simulate a ventilation system is common but applying reasonable shock loss factors in the software is not a simple or direct process. Determining shock loss values includes the consideration of historical measurements, application of factors and formulas from literature based on the geometry and complexity of junctions, and the geometry variation at different locations. For example, the shock loss at the bottom of a ventilation raise can be comprised of a 90° bend and a sudden area change. This paper presents an approach for estimating shock loss factors near raise junctions using computational fluid dynamics. Current and future work will also be compared with field measurements. Results from this approach are compared with software defaults as well as classical techniques in published literature and standards.

May 14, 2024

By Alafara A. Baba, Yakubu A. Dallatu, Kehinde I. Omoniyi, Shemang Y. Chindo, Edith B. Agbaji

As a result of the rise in global demand for pure copper, there is urgent need to consider the processing of low-grade chalcopyrite ores. Ammoniacal leaching solutions have been reported as an effective and efficient leachant for the dissolution of chalcopyrite. This work reports different parameters that influence the leaching kinetics of a Nigerian chalcopyrite-rich siderite ore obtained from Wase Local Government Area, Plateau State, Nigeria, and assayed as 11.30 wt% of Cu. At the optimum leaching conditions (0.4 mol/L NH3-( NH4)2SO4 leachant concentration; 75 °C reaction temperature; 45 μm particle size), the extent of chalcopyrite ore dissolution reached 87.4% within 120 min. The dissolution rate was affirmed to conform to the diffusion control mechanism with the activation energy, Ea, of 38.84 kJ/mol and a reaction order of 0.661 for the leachant concentration being established. The leaching mechanism was affirmed by characterizing the raw ore and the leached product by XRD and SEM-EDS analysis. Ascertaining optimal leaching conditions for copper using alkaline leachant is advantageous from the environment and economic points of view.

Jan 6, 2023

By Mehdi Noori, Atefeh Azizitorghabeh, Fereshteh Rashchi, Ataollah Babakhani, Sarah Mahmoudi

The focus of this research was to evaluate the synergistic effect of bis(2,4,4-trimethylpentyl) phosphinic acid (CYANEX 272) and di-(2-ethylhexyl) phosphoric acid (D2EHPA), diluted in kerosene, on the extraction and separation of Co(II) and Li(I) from synthetic sulfate solution. The results indicated that using a mixture of CYANEX 272 and D2EHPA was efficient in extracting and separating Co(II) from Li(I). The optimum ratio of CYANEX 272/D2EHPA was found to be 5:1, in which the highest separation factor was obtained (5973.23), and ΔpH0.5 was 4.10. Adding tributyl phosphate (TBP) as a modifier and increasing the temperature improved the metals’ separation rate and extraction efficiency. Thermodynamic studies were also carried out, and ΔH, ΔS, and ΔG values were computed, revealing the endothermic nature of Co(II) and Li(I) extraction by CYANEX 272/D2EHPA mixture. The conducted experiments for the McCabe–Thiele diagram showed the possibility of using two stages to extract over 99% of Co(II) and Li(I). Slope analysis and Fourier transform infrared spectroscopy (FT-IR) were employed to comprehend the Co(II) and Li(I) extraction mechanism using a mixture of CYANEX 272 and D2EHPA.

Jan 17, 2022

By A. G. Yapo, T. W. Camm

"Mining plays a key role in the development of modern civilization as a source of essential raw materials and provider of essential fuels, producer of jobs and a factor in support of the international balance of monetary payment (Camm, 2014). Professionals in mining locate, develop, design and manage ore deposits in an environmentally safe and profitable manner. As mineral deposits become increasingly scarce, new challenges face the industry. A current trend is to an increased emphasis on underground mining techniques for deeper deposits. Operations are safer now than before as companies understand better their work environment and the importance of mining responsibly.A continual challenge for the industry is accurately reflecting the costs and selling price of ore. An enduring characteristic of mining is the situation where the market typically determines the price of a commodity; the main control a company has on the bottom line is to control the cost of production.An attempt to bring light and clarity to the cost of their business will give a better idea to investors on the true profitability of the mining business. Gold producers face this struggle to accurately reflect the cost of production while also seeking to attract the interest of the investment community (Hill, 2013). In order to have a consistent format to report on their production costs, leading gold producers, through their alliance inside the World Gold Council (WGC), worked on the adoption of a new cost framework: the all-in sustaining cost (AISC) and all-in cost (AIC).Since 1996, the traditional cash cost reporting has focused only on the mining and processing costs incurred in mining an ounce of gold, which included the costs of goods sold (labor, energy, and consumables costs) and royalties (Table 1). But cash cost reporting ignores many important aspects, like sustaining capital, general and administrative expenses and site rehabilitation at the end of the mine life (Whelan, 2013). The cash cost was used to attract many investors into the business. In fact, the high gross margin (sales minus cash costs) has been promoted in past decades by the industry instead of the net or operating margin. As a result, even when the gold price was high, nearly $61/g ($1,900/oz) in August 2011, gold producers were not reporting excessive profits in their cash flow/income statements, to the disappointment and incomprehension of investors (Milstead, 2014). The truth was simply that the other costs omitted in the traditional cash cost were reducing the apparent profits.The disconnect led to a need for more accurate cost reporting in order to win back investor confidence and provide better understanding of gold mining economics. In 2012, the senior gold mining companies, including Gold Fields, Barrick Gold Corp. and Newmont Mining Corp., worked with the WGC to develop a new measure. This resulted in the June 2013 publication of the new framework AISC and AIC, which has been widely embraced by the sector since Jan. 1, 2014 (WGC, 2013).The adoption of the new cost template would have the dilemma of showing the real profitability of gold mine properties, which might alleviate taxes from governments and legislators, but it might also scare off investors toward more lucrative industries if not winning back their confidence."

Jan 9, 2017

By AJIT SWAIN, SUNATI MOHANTY

The abstract discusses the importance of predicting the dewatering performance of industrial hydrocyclones from laboratory models. It highlights the challenge of scaling up design and operating parameters for efficiency estimation. The paper describes experiments with a 2-inch and 4-inch hydrocyclone using silica sand. It details the development of a model using the Nageswararao hydrocyclone model and a simulator to estimate model parameters. The model is validated with experimental data, and a new model is developed using 4-inch hydrocyclone data. The technique is then extended to predict dimensions for a full-scale dewatering cyclone operating at higher throughput and solid concentration.

Mar 30, 2022

By Gill Montgomery

Although fluorspar is considered an industrial mineral by usage and value, its geological occurrence and the mining and milling methods employed make it more akin to the non-ferrous metal ores. Likewise methods of exploration for it are more like those used in the search for lead and zinc, with which fluorspar is often mixed. In fact, it often takes the mixture of fluorspar, lead, zinc, plus maybe barite to add up to enough recoverable values to make the mineral an ore by definition. This is so true where the fluorspar portion is low grade, perhaps less than 25 percent. Until the development of modern steel milling in World War I times, the invention of aluminum smelting, and development of the fluorine chemical industry and air conditioning, there were few uses for fluorspar aside from ceramic fluxes in the flint glass industry and for uses as glazes for pottery and china. Pure fluorite crystals have long been admired as semi-precious and ornamental minerals of many delicate colors.

Jan 1, 1983

By Xiaolong Bi, Shaohua Luo, Longjiao Chang, Shiyuan Cao, Jianan Liu

The abstract discusses the extraction of silica from nickel laterite ore using a hydrothermal process with sodium hydroxide. The effects of reaction temperature, time, and NaOH-to-ore ratio on silica extraction were investigated. The optimal conditions were determined, achieving over 98% silica extraction. The mechanism involves the reaction of Si in lizardite and quartz with sodium hydroxide, forming sodium silicate solution. Other metals like Mg, Fe, and Ni are enriched in the residue.

Apr 21, 2022

By Roy A. Koski

This paper describes variations in feed characteristics, preparation techniques, response to induration and product quality in pelletizing magnetite concentrates, earthy hematite ore fines, and specular hematite concentrates in grate kiln systems. The Cleveland-Cliffs Iron Company manages plants processing these various materials on the Marquette Iron Range in northern Michigan. The operations include the Humboldt Mining Company, Marquette Iron Mining Company, Empire Iron Mining Company and the Pioneer Pellet Plant. The combined output of the operations is approximately 9,000,000 long tons per year. The Humboldt Mining Company, owned by Ford Motor Company and Cliffs, produces pellets from a specular hematite concentrate. The Empire operation, which processes magnetite ore, is owned by Inland Steel Company, McLouth Steel Corporation, International Harvester and Cliffs. The Pioneer operation, which processes earthy hematite ores, is a joint venture of Republic Steel Corporation, McLouth Steel Corporation, Bethlehem Steel Corporation and Cliffs. The Marquette Iron Mining Company, owned by hones and Laughlin Steel Corporation, International Harvester, Wheeling-Pittsburgh Steel Corporation and Cliffs, produces pellets from specular hematite concentrate at the Republic Mine and Eagle Mills Pellet Plant. With the exception of the Eagle Mills plant, the operations employ the grate-kiln pelletizing system. Descriptions of the Empire, Pioneer and Republic operations, which have a combined capacity of 7,200,000 tons per year, are given in the paper.

Jan 1, 1969

By Eti Purwaningsih, Widi Astuti, Erik Prasetyo

Increasing demand for high-grade manganese (Mn) ore has led to the practice of selective mining, which produced low-grade Mn ore as waste and in the long term could lead to environmental pollution. Research had been carried out to extract Mn from low-grade ore, which mostly exists as black Mn(IV) oxide (MnO2). Most extraction methods involved the reduction of insoluble MnO2 to soluble Mn2+ in acidic media. Metals other than Mn are also transferred to the pregnant leach solution (PLS) during the leaching process, especially iron (Fe). Due to high Mn concentration in PLS, precipitation is considered the best method to isolate Mn from PLS compared with solvent extraction and ion exchange/absorption. However, due to unselective leaching, the presence of Fe in the PLS makes the Mn separation and purification difficult. Therefore, in this research, the parameters affecting the selectivity of Mn over Fe in leaching process were investigated.

By R. N. Gow

Acidic treatment of enargite (Cu3AsS4) dissolves both arsenic and copper from the mineral and then attempts to separate them in the leach solution. The reactivity of enargite was examined in acidic solutions, over the pH range 1-7, to determine a potential range for co-dissolution.. Enargite mineral samples from Butte, MT and Quirivilca, Peru were used as working electrodes in a cyclic voltammetry corrosion cell setup, which were then cycled multiple times over -1000 to 1000 mV. Surface reactions and transitions were characterized using in-situ Raman spectroscopy, which were then compared to updated predominance diagrams for the copper-arsenic-sulfur system from a previous study done under alkaline conditions. The region of co-dissolution is limited to > 600 mV vs. SHE and pH < 1 under the proposed diagram.

Feb 23, 2014

By G. V. R. Landman

In order to obtain a better understanding of the explosion risk at the coal face, anomalies in the ignition sensitivity for different modes of ignition of hybrid mixtures of dust, methane and air were studied. Results indicated that the explosible behaviour of the working environment is highly dependent upon the ignition source and the fuel composition. For example, depending on the ignition source, the same hybrid mixture can be inert or extremely explosible. In conclusion, it is stressed how the explosion risk can be expressed in terms of a safety factor which takes into account the influence of both the fuel and the ignition source.

Jan 1, 1994

By MOHAMMAD R. H. GORAKHKI, Christopher A. Bareither, MANUEL APARICIO, Joseph Scalia IV

The focus of this study was on the evaluation of hydrologic and environmental behavior observed in GeoWaste and waste rock test piles. GeoWaste is a mixture of fast-filtered tailings and waste rock prepared as a tailings-dominated mixture. The two test piles included potentially acid-generating (PAG) waste rock and were operated for 26 months to evaluate whether GeoWaste can suppresses sulfide oxidation and production of metal-rich acid mine drainage relative to PAG waste rock. The test piles were constructed in the shape of truncated 5-m-tall pyramids with 25-m base sides and flat 5-m × 5-m top surfaces. Water content, temperature, electrical conductivity, and oxygen concentration were monitored in four layers and at five locations within each layer in both test piles. In addition, 5-m × 5-m lysimeters were installed at the base of each pile to collect leachate. Approximately 2660 mm of water was added to the surfaces of the test piles via precipitation and irrigation (irrigation ≈ 1050 mm applied at an approximately constant rate for 70 days). The measured saturation, oxygen concentration, electrical conductivity, and temperature in the GeoWaste and waste rock piles suggest more sulfide oxidation occurred in the waste rock pile compared to the GeoWaste pile. Observations from the pile experiments suggest that co-managing mine waste in the form of GeoWaste reduced acid generation compared to waste rock alone due to the lower permeability and unsaturated state of the GeoWaste pile that reduced downward migration of moisture and inhibited drainage.

Mar 31, 2021

By James J. Scott

I welcome this opportunity to speak before the Coal Division of the AIME in such an attractive setting as the Pacific Northwest. With the development of the Centralia project, the Pacific Northwest will have its first major coal-fired thermal electric generating plant. This State has a long history of coal mining that diminished with the passage of coal-fired steamships and locomotives but is now reviving with the growth of electrical power demand. Because this 1,400 row plant is to be supplied with surface-mined coal, it is particularly appropriate that this area be the setting for a talk on factors influencing the growth of surface coal mining in the West. During the course of my talk, I will touch on a number of factors including electric power demand, coal resources, production trends, environmental considerations and trends in State and Federal activities that I feel will influence surface coal mining in the West. Total electric power consumption by the year 2000 is expected to reach 9.4 trillion kilowatt-hours. Predictions of total coal consumption for electric power generation by that year range from a low of 845 million tons to a high of 1,520 million tons, or 2.6 to 4.7 times the amount used for this purpose in 1970.

Jan 1, 1971

By Shenghui Chu, Zhibiao Guo, Dongshan Yang, Yuanxin Zhao, Xiaohui Kuai, Jingwei Gao

The technology of automatically formed roadway without pillars (AFRP) via roof cutting and pressure releasing (RCPR) is a reformatory method for gob-side entry retaining, which automatically creates a roadway by utilizing the fragmenting and expanding properties of rock strata and the mining pressure, to realize a novel technique for coal mining without coal pillars. The Anju Coal Mine is the first kilometer-deep mine where this technology is applied. To conduct a geomechanical model experiment, this research uses the 5307 working face in this mine as its backdrop. The experimental results show that this technology can efficiently decrease the pressure of the AFRP surrounding rock. The roof maximum stress of the AFRP is 21% lower than that of the belt roadway, while the side abutment pressure of the former is 13.4% lower than that of the latter. The comparison of model experiment data and field monitoring data shows that the roof and floor approaching deformations on the roof-cutting side and solid coal side of AFRP differ by 8.8% and 9.6%, respectively. The model experiment results and field monitoring data show good agreement, and the deformation of the AFRP surrounding rock can be successfully managed by this technique. The study’s findings can serve as a guide for using this technology in kilometer-deep coal mines.

Jul 31, 2023