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By W. J. Nosek

Reserve Mining Company completed construction on a major process modification project in June of 1980. These modifications enabled Reserve to reduce and control its final iron ore pellet silica content from 9.0 20.77 percent to 5.0 50.26 percent. The paper outlines the implementation of neutron activation on-line analysis and associated computer control loops for measuring and closely controlling the silica content of the iron ore concentrate at Reserve Mining Company. It contains a general overview of Reserve's taconite processing facilities and a presentation of the theory and operation of the neutron activation analysis equipment coupled with the computer silica control loops.

Jan 1, 1983

By L. F. Ruppert, R. C. Milici

Coalbed methane (CBM) is currently being produced from a relatively small area in the Dunkard and Pocahontas basins, in the northern and central parts of the Appalachian Basin, respectively. In general, much of the production occurs where the coal beds are beneath 500 feet or more of overburden, where the rank of the coal is high-volatile B or greater (%Ro >0.8), and where the natural fracture system is enhanced by structural deformation. It is anticipated that near-term CBM development will continue within these areas and will expand in the Appalachian basin as technology improves and as the price of gas rises.

Jan 1, 2003

By Debasis Barman

TBM (TBM) mining in urban areas particularly under low overburden is a big challenge to design and excavate. During excavation of the Lucknow Metro project, in Uttar Pradesh, India the metro authorities encountered a design stretch where the TBM had to cross a sewer canal crossing of 15 m length under overburden of less than 1 m. Not only the stability of TBM due to uplift was of concern but also the stability of both banks. Most structures on the canal banks were non-engineered structures whose stability due to vibration of TBM was also of concern. Due to these risks, a method was proposed that met stability requirements for both ground and superstructures. The design was practical and cost effective to construct, and a collaborative exercise between the client, contractor and designer that took approximately 18 months to implement.

Jun 13, 2023

By Roger Malmström, H. Heden, Kjell Lidin

INTRODUCTION LKAB was formed at the turn of the century when the railways between the ore fields and harbors were built. The mines are situated north of the Arctic Circle in Sweden. Kiirunavaara is the largest mine, with a pro¬duction capacity of approximately 30 Mt/a. Malm¬berget has a capacity of about 12 Mt/ a. Both are under¬ground mines. Svappavaara, the only opencast mine currently in operation, has a capacity of about 4.5 Mt/a. The ore harbors are at Narvik for the Kiruna and Svappavaara mines and at Lulea for the Malmberget mine (see Fig. 1). Production in the form of finished products is shown in Fig. 2a, b, c, and d. Due to poor ore markets in re¬cent years, production and shipments have been cut back, but there was a positive swing in 1978. LKAB has been 96% state-owned since 1957. In addition to the iron mines in northern Sweden, LKAB has subsidiaries in central Sweden which produce sulfide ores, quartz sand, and uranium (Fig. 3). The mining methods employed are opencast bench stoping at Svappavaara and sublevel caving at Kiirunavaara and Malmberget. GEOLOGY The Kiirunavaara ore body is 4000 m long and av¬erages about 90 m wide, with variations in width from a few meters to around 150 m. The ore has been ex¬plored by deep drilling down to about 1000 m, but mag¬netic measurements indicate a depth of at least 1500 m. The Kiirunavaara ore is oriented in a north-northeasterly direction with a number of ores in the boundaries be¬tween the wall rock types. The ore in Kiirunavaara is mainly a fine-grained magnetite with a varying content of fine-grained apatite. The apatite content of the ore decreases with increasing depth. The other ores are all apatite-bearing and a couple are hematite ores (Fig. 4a, b). The ores are sedimentary, tilted, and tectonically de¬formed. They have a lateral dip of 0.87 to 1.2 rad (50 to 70°). The contacts between ore and wall rock are distinct and sharp, but both the hanging wall and the footwall are brecciated and impregnated with magnetite. The footwall of the Kiirunavaara ore consists of syenite porphyry with a low quartz content and rela¬tively good strength; the hanging wall consists of quartz porphyry. Both types are known as Kiruna porphyries. The ore at the boundary with the hanging wall is often rich in kaolin. There are a few veins of syenite porphyry running through the ore, which has a few major faults (Fig. 4c, d). There are two sharply delineated ore grades in Kiirunavaara: low phosphorus ore with less than 0.1 % phosphorus (about one-third of the ore) and high phos¬phorus ore with greater than 0.5% phosphorus. The iron content is 67% in the low phosphorus ore and 60% in the high phosphorus ore. These ore types are sold as different grades and so are kept separate during mining. MINING AT KIIRUNAVAARA The Kiirunavaara and Luossavaara ores were first mined using opencast bench stoping in 1902. When mining costs rose owing to higher waste removal, under¬ground methods were adopted. In the mid-1950s, the ores were still being mined on the surface at the same

Jan 1, 1982

By Kevin Saeler, Patrick Willaman

Utilizing automation is one way to improve competitiveness. Roof and rib bolting in underground coal mines has not changed significantly for more than 40 years. Most roof bolting is still a largely manual process involving high levels of staff carrying out repetitive work. Roof bolting statistically has one of the highest levels of underground accidents, including finger, hand, and arm injuries. Operators are exposed to falling objects and becoming entangled in roof bolting apparatus while roughly moving awkward 6-ft drill steels and roof bolts. It is estimated that over 25 million roof bolts are installed annually in the U.S. underground coal market with well over 1,500 operators involved in roof bolting on a day-to-day basis. Recently electrohydraulic roof bolting rigs have been installed to offer partial automation of the drilling cycle and the bolting cycle. The next stage is to provide a storage and loading system to allow full automation of fullcolumn resin roof bolts. This paper reviews the latest electrohydraulic roof bolting equipment and discusses the testing of a fully automated drill rig. Full electronic control allows each step of the roof bolting process to be recorded, providing a digital record of each installation, including hole depth, spin time, gel time, torque, and cycle time. Other benefits include monitoring of water pressure and flow, used to prevent blocked drill steels as well as digital fault finding. A fully automated roof bolting machine greatly improves operator safety and gives high-quality repeatable roof bolting with reduced cycle times.

Jul 1, 2023

By R. C. Richardson

Barite Worldwide barite production for 1985 decreased 1.3%, while US barite production increased 1.4%, according to US Bureau of Mines statistics. The increase in US production is attributed to heavy demand for oil and gas drilling during the first quarter and an unrealized heavy expected demand in oil and gas markets for the last quarter. Nevada accounted for 82.1% of the 807 kt (890,000 st) of barite produced in the US last year, according to the Bureau. Other producing states were California, Georgia, Illinois, Missouri, Montana, Tennessee, and Washington. In 1985, the US imported 1.8 Mt (2 million st) of crude barite and 64 kt (71,000 st) of ground barite. China led the way with 43.3% of the total. Imports from India accounted for 21.6%; Morocco, 15.5%; and Thailand, 5.6%. The 1.8 Mt (2 million st) of crude barite imported is an 18.8% increase over 1984. Apparent consumption of barite for 1985 was about 2.6 Mt (2.9 million st), a 15.7% increase from 1984. Due to very low drilling rig activity during the last quarter of 1985, actual consumption is probably less as crude barite inventories at mines and plants increased. According to the Bureau, 90% of barite consumed in 1985 was for the oil and gas market. Paints, rubber, glass, and other chemical uses consumed the other 10%. With the price of oil falling dramatically early in 1986, the outlook for oil and gas drilling looks to be significantly lower than 1985. This lower demand for barite, coupled with the high year-end inventories, should lower both imports and domestic production. Significant lower prices on imported barite are expected, especially from China, Morocco, and India. This also could further lower US production of barite this year.

Jan 5, 1986

By R. Gradnik

The continuous need for infrastructure expansion forces the mining industry to develop underground structures into more sensitive and violent environments. When underground excavation enters into deep and high stress rock conditions, geotechnical designers find themselves faced with the difficult task of selecting a rock support system that will meet today's stringent requirements. Whatever support system is chosen, it is mandatory that potential rock movement be controlled. All this has intensified the development of safety systems and new, unique solutions which can enable construction companies to go both, further and deeper, without reducing the level of safety. To address these needs, Atlas Copco developed the Roofex® bolt, specifically designed to withstand large static and dynamic deformations under prespecified load conditions. The Roofex Rock Bolt acts as stiff support up to a designable load level before the sliding effect of the mechanical frictional system is triggered and allows highly controlled rock mass movement without loosing the support function.

Jan 1, 2011

By K. K. Kohli

Since the adoption of the Surface Mining Reclamation and Control Act of 1977, which mandates that surface subsidence be an intergral part of the underground coal mine design, there has been a sudden rise of demand on guidelines for minimizing surface subsidence and its associated structural damages. Unfortunately there is no sufficient amount of systematic subsidence data to fill such a gap, although considerable research has been devoted to the subsidence-induced damages of surface structures in the past. However, it was said that many surface subsidence surveys have been performed and monitored by coal companies during the past twenty years, and that it will be a great source of information for subsidence engineering design if they can be collected and assembled together. An effort was therefore initiated in the Department of Mining Engineering, West Virginia University, under contract with the U. S. Bureau of Mines in December 1978 to contact each individual coal company in the Northern Appalachian Coal Field for any surface subsidence survey data. After 10 months' survey, the data collected include 17 longwall panels and 2 room and pillar sections. The data in-each panel and section cover the complete set of subsidence survey raw data, underground mine layout maps, surface topo maps, geological loggings showing the stratigraphic sequences and thickness of the overburden, and if available, locations and types of surface structures. On-site visits were followed to study the surface terraines and structures. Interviews were conducted with the owners of the surface structures in most cases about, if any, the history and characteristics of damages.

Jan 1, 1980

By Robert C. Pease

Siskon Gold has started gold production at the San Juan deposit in northern California. The mine is located about 27 km (17 miles) north of Nevada City, CA (Fig. 1). It is scheduled to be-come the largest underground gold mine in California. It is situated in the western foothills of the Sierra Nevada Mountains in the Mother Lode gold belt. The property consists of 8 km2 (2,000 acres) of patented land. It is situated in a topographically high area known as San Juan Ridge, which is 213 m (700 ft) above and between the Middle Yuba and South Yuba rivers. The elevation is between 790 and 914 m (2,600 and 3,000ft) above sea level. Annual precipitation averages 1,346mm (53 in.). Most of that falls between November and April.

Jan 1, 1996

By Paul Wellman

The energy problem of the U. S; was emphasized by the oil embargo of late 1973 and early 1974 and it seemed for a time that the Federal Government, under pressure from the general public, might take some corrective action. However, this was not the case. With the gasoline lines gone and an apparent plentiful supply of petroleum products, public concern quickly dissipated., This country is more vulnerable to an oil embargo today than we were in 1973-1974 and this fact should be of concern to all our people. Since 1968, we have used oil and natural gas at a much more rapid rate than we have been able to find new domestic sources; thus, there is an increasing gap between domestic production and consumption and we have filled the gap with ever increasing oil' imports. These imports have increased at an alarming rate in the recent past, some 58 percent in 1976 compared with 1975. Imports are nearing 8 million barrels per day. Then, by applying some simple arithmetic, at $12 per barrel, the resulting trade deficit is $96 million per day or $35 billion per year. Obviously, this cannot be tolerated by our economy over a long period of time. Historically, we have shifted from one fuel to another as is shown in this slide. In 1850 about 90 percent of our fuel requirements came from direct combustion of wood, by 1900 we shifted to coal for 70 percent of our fuel, and now about 78 percent of fuel requirements comes from oil and natural gas. The difference is that the previous shifts were voluntary and the one facing us now is of necessity.

Jan 1, 1977

By M. Paul

"INTRODUCTION In 1990, the uranium production of SDAG Wismut in East Germany was stopped. 45 years of inconsiderate destructive exploitation had scarred both landscape and nature. With the “Wismut law” which came into force in December 1991, the Federal Republic took responsibility of the remediation of the legacies from former uranium ore mining and milling in Saxony and Thuringia. A unique opportunity turned out in order to remove environmental damage, to enhance the life quality of the local population, to shape new landscapes and to advance the economic restart. (1) The results of nearly 25 years of remediation activity are evidence that this opportunity was used at all former SDAG (Sowjetisch-Deutsche Aktien-gesellschaft) Wismut sites. The reference project “Wismut“ has evolved into a joint project of all parties involved and radiates beyond the affected regions. This is particularly reflected by the Know-how transfer starting from Wismut and the increasing activities for third parties abroad.WATER MANAGEMENT AT WISMUT REHABILITATION Within the Wismut project, water management and conventional technical water treatment are by far the most cost-intensive long-term tasks of the remediation programme. Over the medium term, there is no viable alternative to the operation of active systems to catch and treat contaminated mine waters at the Ronneburg, Schlema, Königstein, Pöhla, Seelingstädt and Helmsdorf sites. Based on the status quo, this paper outlines the key issues of the Wismut GmbH water management strategy over the medium and long term. It is focused primarily on achieving protection goals for potentially impacted water bodies in the surroundings of Wismut sites and on optimising associated remediation expenditures as well as on creating the prerequisites for achieving low post-remedial care and maintenance or walk-away system status over the long term. (2) The applied mining practices during the active SDAG Wismut period have not been up to the high standards of modern mining operations and their requirement to leave former production premises and deposited residues in a condition that was not only physically but also chemically stable. Rather the emission of mine and seepage waters laden with high acidity, metal and salt content is a frequent corollary and difficult legacy of historic mining and processing operations (4, 5). As a consequence, the control or mitigation, respectively, of environmental impacts associated with contaminated mine waters ties up enormous public resources worldwide (6, 7)."

Jan 1, 2016

By Richard C. Corson

The new 9300 TPD sinter plant being built for China Steel Corporation is incorporating the latest computer technology for plant control systems. The control system will use a central computer and distributed micro-processors to control instrument loops and switching logic in the blending yard and sintering plant. All plant functions, including combustion and fan controls, will be controlled by remote microprocessors located throughout the plant, and connected by a communications link to the centrally located computer and control room. The design, programming, construction and operation of a microprocessor based control system presents new challenges to the control engineer. With microprocessors in the control system, more power exists in the individual control loop and many supervisory functions may be added at the loop level. The specification of the microprocessor system and the resolution of hardware design and control system design can lead to development of powerful systems capable of higher level control and optimization functions

Jan 1, 1981

By M. Gomilanovic

The Republic of Monte Negro (a member of the Serbia and Monte Negro federation) has 26 different mineral raw materials, 4 of which are recoverable and 22 unrecoverable. At present, 12 types of mineral raw materials are exploited. Based on these resources more than 80 facilities were built for the production and processing of mineral raw materials. The most significant of them are coal, bauxite and decorative and technical stone. Bearing in mind that all the mentioned mining facilities have significant impact on the living environment, and that Monte Negro was declared the ecological state, the objective of this paper is to present the experience acquired from this field of science.

Jan 1, 2003

By D. E. Nash

Environmental compliance programs for mining companies are not only important management tools, but can deflect serious civil and criminal penalties if violations of environmental laws do occur. The paper discusses the legal foundation for such programs and their basic structure.

Jan 1, 2001

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

"All-in sustaining cost is a metric used by mining companies to reflect the cost of gold mining in a consistent format useful to both investors and mining professionals. Cost reporting focused on the direct cost of mining and processing ore was summarized in the non-GAAP cash cost developed by the Gold Institute in 1996. In 2013, a group of mining companies, working with the World Gold Council, developed a more inclusive approach to reporting costs designed to solve the dilemma of showing a more comprehensive reflection of recurring costs involved in producing gold, without discouraging investors. INTRODUCTION Mining today plays a key role in the development of our civilization as a source of essential raw material 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 today 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 on 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 the past decades by the industry instead of the net or operating margin. As a result, even when the gold price was high, nearly $1900 per ounce 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."

Jan 1, 2017

By Andrew Scogings

The current edition of The Australasian Joint Ore Reserves Committee (JORC) Code was published in 2012 and, after a transition period, the 2012 edition came into mandatory operation on Dec. 1, 2013. There is a significant change between JORC 2004 (Clause 44) and JORC 2012 (Clause 49) for the reporting of industrial mineral resources and reserves, which should be addressed by ASX-listed players in the industrial minerals space.

By Jon Pocock, Ashma Singh

The traditional approach for the beneficiation of South African siliceous sedimentary phosphate ores has been reverse cationic flotation. The robustness of this approach, however, has been a concern due to its sensitivity to parameters such as slimes content, headgrade ( P2O5 and SiO2 content), reagent dosages and conditioning times. The phosphate mineralisation for the ore body under investigation is predominantly carbonate fluorapatite composed of mainly quartz and apatite and minor amounts of chlorite, ilmenite and carbonates. Beneficiation of low grade sedimentary ores containing calcareous impurities, such as calcite and/or dolomite in addition to siliceous gangue, is required to meet the increasing demand; therefore, much research has been carried out to find an alternative technique to beneficiate this material. This paper investigates traditional flotation approaches versus the currently adopted ‘Crago Process’. Comparative results are presented in terms of upgrade potential for the production of concentrate rock for downstream applications. The novelty of the ‘Crago Process’ lies in its double stage approach, i.e. direct fatty acid flotation followed by reverse cationic amine flotation. The Crago process was able to achieve higher upgrades reporting at 32.1% P2O5 compared to conventional cationic flotation only achieving grades of 18.5% P2O5. Furthermore, the recovery gain was 3%.

May 13, 2023

By Hai Lin, Renshu Yang, Yongliang Li, Shizheng Fang

With the aim of solving the large deformation problem of surrounding rock in coal mine roadways with a thin sand-mudstone interbed roof, transportation roadway 1603 in Haoyuan Mine was considered. The failure mechanism of surrounding rock was studied through comprehensive on-site investigations, borehole image analysis, mineral composition analysis, and other means. Numerical simulations were performed to determine the influence of roof layer thickness, lateral pressure coefficient, and coal rib strength on the stability of the interbedded roof. The main reasons for support failure and deformation of the roadway are softening and swelling of the sand-mudstone interbed roof upon exposure to water, insufficient support capacity of the roof due to the soft coal rib, an unreasonable support scheme, or poor construction quality, which can reduce the bearing capacity of surrounding rock. Based on our analysis, a control strategy was devised for a thin coal-mudstone interbed roof. The support scheme combines long and short cable support, strengthening of the coal rib to consolidate the roof, and partially shotcrete grout, and was found to improve the overall mechanical strength of surrounding rock and maintain the stability of the thin sand-mudstone interbed roof. The results of the numerical simulations and monitoring data indicated that the proposed support scheme effectively controls the deformation of the surrounding rock of thin sand-mudstone interbed roof of coal mine roadways while maintaining the safety and stability of the surrounding rock and supporting structure.

Dec 12, 2022

By Theodore S. Jordan

The discovery of a major porphyry-type copper deposit on the Papago Indian Reservation in Pinal County, Arizona was announced by El Paso Natural Gas Company in 1968. The deposit, known as the Lakeshore Property, contained an estimated 470 million tons of sulfides and oxides averaging 0.75 percent copper. History and Geology of the area have been described by Harper and Reynolds (1969). El Paso subsequently&apos; entered into the agreement for joint development of the property with Hecla Mining Company, with Hecla as the operator. The ore body consisted of three types of mineralization: 1) Disseminated Oxide Ore, <1% Cu 2) Disseminated Sulfide Ore, <1% Cu 3) Tactite Ore, >1% Cu

Jan 1, 1985

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