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By J. W. Paul

The material that composes the roof in coal mines differs in strength according to variations in its physical nature and characteristics. Some material such as limestone and massive sandstone, (free from slits) and carbonaceous shale or bone, will often remain in place in narrow work without the use of timber or other means of support, but in wide places the use of supports becomes a real necessity. Roof material composed of shale, fire clay or small laminations of sandstone, or shale or sandstone interspersed with laminations of thin coal, presents conditions that call for timber support in both narrow and wide work. However, in narrow work such unstable roof material may be taken down until the strata assume an arch that is self-supporting for overlying firm strata such as a roof coal, a touch weather-resisting, shale, sandstone, or limestone. The proper support of the roof in roadways used for haulage or travel adds to the economy of operation by preventing delays in transportation and increases the safety of those who travel these roadways.

Jan 1, 1930

By Sumit Kumar Hota, Asadi Srinivasa Reddy, Ashok Kumar, Ashish Agrawal, Surajit Sinha, Chandra Sekhar, Tanay Ray

In the current operational facility, due to the absence of pellet pot facility, a novel technique is developed wherein the pellets with different chemistries prepared in the laboratory are fired in an induration machine by placing them inside the Inconel baskets. In the present work, an attempt is made to optimize the pellet chemistry by developing 2 different flux pellets, viz., low basicity (B2: CaO/ SiO2 = 0.3) pellets and high basicity (B2 = 0.9) pellets, and further the effects of basicity on pellet properties, viz., cold compressive strength, porosity, swelling index, reducibility index, and softening and melting temperature, are studied. It has been found through the multiple operational trials that increasing the basicity of pellets from 0.3 to 0.9 results into improving the pellet strength, reducibility and softening and melting characteristics. Moreover, it is observed that the swelling index of pellets is reduced by adding 2% MgO to both low and high basicity pellets that could be attributed to the formation of high melting point slag in pellets. The operational trial has resulted into producing pellets that exhibit a combination of desired mechanical strength, improved swelling, and reducibility index and possess better softening–melting behavior among all the chemistries studied.

May 24, 2022

By Michael Moran

Typical ACIP Pile Rig [ ] Hollow Stem Auger ? Continuous flight auger ? 3 inch inside diameter pipe ? Auger diameters: 12, 14, 16, 18, 20, 22, 24, 30, and 36 inches ? Auger section lengths: 4, 5, 10, and 20 ft ? Weight ranges from about 70 lbs per ft for 12 inch to 120 lbs per ft for 24 inch and 200 lbs per ft for 36 inch

Jan 1, 2005

By Madan M. Singh

A new mining project can raise questions about what effect it will have on the community after it closes. Historically, little was done by communities to plan for and accommodate the changes in the economic infrastructure when a mine project is finished either after the ore runs out or if market conditions deteriorate and make it unprofitable. Projects that were underfunded were generally unable to withstand periodic market downturns. However, data in a recent study conducted by the Seidman Research Institute leads to the conclusion that, even when a mining project is terminated, there can be (and, in the specific case studied, is) a residual beneficial economic effect in the community, which lasts for a long period of time.

Jan 1, 2010

By James M. Barker

No commodity agreements now exist for sulfur and a lack of reference to sulfur commodity agreements exists in the literature. Law (1975) made a passing reference to sulfur as one of a group of commodities where "there have been additional control efforts of various types." Clearly, sulfur was a candidate, at least conceptually in the past, for some form of commodity agreement and the following discussion centers on the world sulfur market of the early 1980's in this context. GENERAL THEORY OF COMMODITY AGREEMENTS The upsurge in demands for commodity agreements seen in the last decade or so stems largely from agitation by the less developed countries (LDC) for better economic treatment by more developed countries (MDC). Several economic factors, real or imagined, adversely affect the LDC's as follows (MacAvoy, 1977): 1) variable demand in MDC's causes wide fluctuations in commodity prices which hurt the economies of commodity producers, who are often LDC's although consumer economies may also benefit from more predictable prices; 2) a general decline of commodity prices relative to the price of manufactured goods which hurts commodity producers in their balance of trade while their stocks and overcapacity rise; 3) instability of LDC economies enhanced by the above factors lowers internal stability, inhibits foreign investment, and retards economic growth; and 4) a lack of self respect when dealing with developed countries o, following the OPEC lead, LDC producers want the stature related to cartel market power.

Jan 1, 1985

By Andrew Chegwidden, Tara Wilk

Shaft 18B-1 is the second shaft to be constructed as a part of contract C547A along the New York City water supply system Tunnel No. 3. More complex than Shaft 17B-1, this site has an additional 30 m (100 ft) of overburden for a total excavation depth of approximately 78 m (256 ft) through water-bearing overburden soil and 145 m (475 feet) of gneiss bedrock to connect to the underlying Water Tunnel No. 3. round freeing was specied as the method to provide temporary earth support and ground water control for the overburden material. An extensive supplemental geotechnical investigation (SGI) and frozen soil testing program was performed to develop the design of a temporary ground freezing system, consisting of over 7,315 m (24,000 ft or 4.5 miles) of drilling for the installation of 95 freeze pipes. At the start of shaft excavation, the upper sandy silts strata was found to have an unprecedented low thermal conductivity, leaving the frozen soil face approximately 0.6 to 1 m (2–3 ft) behind the cutline. The ground freezing earth support needed to be augmented with ring beams and liner plates to support this soil face and allow for the excavation to proceed and be completed safely.

Jun 23, 2024

By H. Maleki, B. Jaramillo

La importancia de los diseños de pilares de acceso y de barrera, para el control del estrés y la sismicidad se demuestra utilizando datos geotécnicos y el monitoreo del estrés en tres estudios de casos. Los esfuerzos para eliminar los pilares de barrera fracasan en el primer estudio, mientras que una barrera de tamaño marginal contribuye a un evento sísmico de 4.2 en la segunda mina estudiada, la cual se ubica a una profundidad de 760 m. Por el contrario, la efectividad de un pilar de barrera de 150 m de ancho se muestra en el tercer caso, en las condiciones litológicas rígidas que caracterizan a Utah. El estudio confirma una reducción notable en el número de eventos por kilómetro (un factor de 4 a 8), en comparación con el distrito minero inicial en el que se usa la extracción de carbón por el método de pared larga de lado a lado (Long Wall).

Mar 30, 2020

By K. C. Grogan

"GeneralGIANT ORE is complex, with the gold values for the most part occurring in extremely close association with arsenopyrite, stibnite, jamesonite, and a wide group of antimonial minerals locally termed 'the grey minerals'. Pyrite is the most abundant of the sulphide minerals• and minor quantities of chalcopyrite, galena, and sphalerite also occur. Pyrrhotite has been found in some sections of the mine, but to date none of it has been nickeliferous. Native gold occurs in varying amounts throughout the ore bodies.In 1944, ore dressing investigations were commenced on diamond-drill core rejects and samples of surface outcrop ore. Results soon indicated that treatment to produce satisfactory recovery of the gold values would involve fine grinding to 80-85 per cent minus 200 mesh, recovery of free gold by jigs, followed by flotation, roasting of the flotation concentrate, and subsequent cyanidation of the calcine. Proceeding from this information, the flow-sheet was prepared, plant design worked out, equipment purchased, and construction of the treatment plant commenced in May, 1947.The crushing, grinding, and flotation units of the plant were rushed to completion and commenced operation on May 12th, l.948, at 225 tons of ore per day. This rate was maintained until January 27th, 1949, when the Allis-Chalmers roaster and cyanide plants were completed and commenced operation. During the period May 12th, 1948, to January 27th, 1949, gold recovered by amalgamation was the sole source of revenue. Flotation concentrate was stockpiled pending the completion of the Allis~Chalmers roaster and cyanide plants."

Jan 1, 1953

Organization Place Date 1917 American Institute of Architects Philadelphia,.,; Pa. Dec. 26-29 American Society of Mechanical Engineers New York City. Dec. 26-29 American Mining Congress State Chapter Phoenix, Ariz. Dec. 26-29

Jan 11, 1917

By D. J. Singleton

Erosion corrosion of 12 alloys in phosphoric acid waste water was studied by the Bureau of Mines. Tests were conducted on oblate spheroids or cylindrical specimens in 12-and 60-cm-diam ball mills by grinding phosphate rock in gypsum pond water with a starting pH of 1.6. For comparison, tests were conducted while grinding phosphate rock in plain water. Static corrosion tests in gypsum pond water also were conducted. For all alloys, the wear by erosion-corrosion (milling with gypsum pond water) was greater than the sum of erosion (milling with water) plus static corrosion. Erosion-corrosion wear was about 1,500 to 3,000 mpy for the alloyed white cast irons, 1,000 to 1,400 mpy for commercial steel ball material and type 316 stainless steel, and 600 to 900 mpy for nickel-base alloys and a high-manganese, nitrided stainless steel. Alloy costs per unit of phosphate rock 'processed favor a low-alloy, high-carbon steel or a high-manganese, nitrided stainless steel.

Jan 1, 1985

By L., Ormsby

DRILLING and blasting practices in the Morenci open pit have undergone considerable modification in recent years. Changes in the character of the ground being mined, modifications of working conditions, and continuous experimentation have been the contributing factors.

Jan 1, 1950

By A. W. Decora

Gas-liquid chromatography has been applied to separating basic nitrogen compounds, such as pyridines and amines. Close-boiling compounds have been separated by exploiting structural and polarity differences, using selective liquid substrates dispersed on specially prepared solid supports. Development of these special supports was necessary in order to obtain symmetric peaks for basic nitrogen compounds; solution of this problem was important in applying gas-liquid chromatography to the analysis of basic nitrogen compounds found in shale oil. Attempts to analyze shale-oil tar bases by conventional gas-liquid chromatographic techniques, using Chromosorb4/ or Celite 545 as the support for a nonpolar liquid substrate, resulted in asymmetric peaks. These asymmetries were caused by adsorption of sample vapors on the solid support. Symmetric peaks were obtained when strongly polar liquid substrates were used on either Chromosorb or Celite. However, a solid support giving symmetric peaks only with strong polar substrates restricts the choice of substrate, and frequently, desired separations cannot be achieved.

Jan 1, 1961

By N. A. White

Whereas the ultimate world supply of energy minerals-defined as fossil fuels and fissile materials - is controlled by geological factors, the actual supply at any particular time is controlled by economic feasibility, technological innovations and /or political decisions. This paper identifies and discusses the principal uncertainties surrounding the international availability of energy minerals from now until the end of the century. A brief comparison is also made between energy and non-energy minerals. Genuine shortage s of energy minerals are now of a very long-term nature, whereas artificial ones may occur at any time and have a serious effect on the world economy due to the dependence of most OECD countries on imports of energy mineral . This paper argues that events over the last decade, such as the demand for a New International Economic Order, the OPEC increase in crude oil prices and the growing international lobby on environmental issues especially relating to nuclear safety - will progressively lead to a major, long-lasting transformation of the energy scene world wide. This transformation will encompass demand, in terms of conservation and efficiency, the supply mix of the various energy minerals , the supply system and the structure of the different energy industries . It is already affecting the role of governments and reaching into the question of national sovereignty both of developed countries, such as the U.K., Norway and Australia, and the developing countries, thereby making energy minerals a key area of international relations.

Jan 1, 1978

By W. A. Dunkley, W. W. Odell

About two-thirds of the manufactured gas supplied to the public by the gas plants in the Illinois district is cnrbureted water gas. The leading generator fuel is coke, ma.de in by-product c.oke ovens or in retorts, chiefly from eastern gas coals. During the fall and winter of 1917-18, when the demand for coke by war industries and the restrictions of the Fuel Administration in connection with the transportation of coke from eastern States made it almost impossible for many gas companies to obtain their coke requireml'nts, several water-gas plants had to use bituminous coal as generator fud. Many operating difficulties were encountered, some of which were solved more or less satisfactorily in different plants. A number of plants attacked the problem rather blindly because facilities for making tests were lacking and because technical men were too busy with labor and supply problems to study thoroughly the conditions involved or to ascertain what other plants had done with this fuel. It was therefore with the hope of assisting the gas industry during this critical period, and of promoting the use of Central District coals for gas making, that the Illinois Mining Investigations, a joint agency of the U. S. Bureau of Mines, the University of Illinois, and the Illinois Geological Survey Division undertook the, tests discussed in this paper. • This report was compiled under the auspices of a technical committee appointed by Gov. Frank 0. Lowden to promote the use of Central District coals in gas manufacture as a war measure. This committee included the following representatives of the various agencies concerned: U. S. Bureau of Mines, E. A. Holbrook and W. W. Odell; Illinois Gas Association, C. W. Bradley and R. B. Harper; University of Illinois, Dean C. R. Richards, Prof. S. W. Parr, and Prof. H. H. Stoek; State Geological Survey Division, F. W. De Wolf, G. H. Cady, a.nd W. A. Dunkley. F. W. De Wolf was chairxnan of the committee and E. A. Holbrook was secretary.

Jan 1, 1924

By B. Erdem, N. Çelebi

An important problem associated with tandem dragline systems is that of matching the productive capability of individual draglines in the combination. In this paper, a dependence mechanism among draglines in a tandem system is described, and possible consequential problems in a poorly-matched system are defined. The rate of linear advance and the cost of stripping are determined as two major indications for an efficient operation. The proposed decision criteria and the underlying mechanism to select a synchronous couple are introduced and used in simulating tandem dragline systems. The developed model is tested on a hypothetical strip mine where pullback stripping is applied with a tandem dragline system.

Jan 1, 1999

By John P. Powell

The increasing demands for petroleum and its products and the steadily increasing cost of discovering and developing new oil fields are factors that emphasize the importance of increasing the recovery of oil from known petroleum reserves. Water flooding is a valuable conservation measure, not only preventing premature abandonment of stripper leases but also reviving interest in many areas previously abandoned. The use of water flooding as a means for recovering additional oil from partly depleted oil-bearing formations was first tried in Oklahoma in 1931. Early water-flooding operations were confined to the area of shallow Bartlesville-sand formations in Nowata and Rogers Counties, where many of the projects were outstandingly successful. The results of these operations stimulated activities in other pools in Oklahoma, and by the end of 1949 water flooding had been tried in 25 of the 49 oil-producing counties in the State (fig. 1). Approximately 33 million barrels of oil, or 1,806 barrels per acre, had been recovered by December 31, 1949, from 18,221 productive acres included in the 162 active and abandoned projects in Oklahoma by injection of approximately 449 million barrels of water.

Jan 1, 1952

By José Maria Silva, Eugênio Oliveira, Ruberlan Silva, Thiago Souza, Lucas Reis, Lorena Guimarães, Matheus Bianchetti

Copper mine operations consistently generate a large quantity of tailings after their concentration processing. These tailings are either piled up or stored in a dam, where both alternatives of disposal lead to environmental impacts. The dam copper tailings have a huge potential for by-product production thus improving sustainability and profitability in industrial operations. This paper describes a study aiming at producing a magnetite pellet feed as a by-product from a dam chalcopyrite flotation tailings and generating free magnetite non-magnetic rougher tailings. The chemical assay and mineralogy analysis of dam copper flotation tailings indicate low Fe grade (6.34 wt%), high SiO2 grade (63.14 wt%), low magnetite (3.6 wt%), and high iron silicates content (22.72 wt%). The complex mineralogy of these tailings leads to the need of grinding the rougher magnetite pellet feed as fine as 80% of particles smaller than 20 μm ( P80) aiming at improving magnetite liberation. The proposed process route comprises a scalping screen, low field rougher, and cleaner magnetic separations using a drum magnetic separator (80 kA/m or 1000 Gauss), followed by silicates reverse cationic flotation as a recleaner step. With this process route, it was possible to produce a high-quality magnetite pellet feed reaching 68.00 wt% of Fe, 2.13 wt% of SiO2, 0.51 wt% of Al2O3, and 95.1 wt% of magnetite. The Blaine specific surface area was 2300 cm2/ g, being in the range recommended for pelletizing (1900 up to 3000 cm2/ g). The total mass, Fe, SiO2, Al2O3, and magnetite recoveries were 2.77%, 29.71%, 0.09%, 0.12%, and 73.17%, respectively. Most of the magnetite losses, around 20% of total magnetite fed, occurred in the oversize of the scalping screen. Additionally, it generated non-magnetic rougher tailings with less than 1.0 wt% of magnetite that could be used as by-products and reduced the amount of tailings disposal in a dam. This study contributes toward the sustainability of operation, minimizing tailings disposal.

Sep 28, 2022

By Tassos Grammatikopoulos, Mike Johnson, Niels Verbaan

Seabed polymetallic nodules, which contain significant quantities of metals key to electrification (nickel, cobalt, copper, and manganese) can be processed using several different metallurgical processing options, including direct smelting and subsequent hydrometallurgical refining of the copper/nickel matte, ammoniacal leaching (gas reduction or Cuprion), and acid leaching (often reductive). Many of these approaches suffer from reduced cobalt extraction, difficult physical performance, or overall circuit complexity in general, leading to increased risk to the overall project. SGS has considered pressure acid leaching of nodules for further investigation, as publicly shared data on this processing route stems from the 1970s and 1980s and is not always easily accessible. This paper will detail the series of tests conducted and provide updated results obtained (high Ni/Co/Cu recovery with limited Mn/Fe), as well as comment on the potential treatment options on the product solution and residue.

Feb 1, 2025

By Z. Zhang, M. S. Gonzalez, M. de P. Bueno, P. Holopainen, S. Luukkanen

"Despite being a field of study that requires practical knowledge and experience, mining engineering education follows the same pattern in most mining universities around the world, consisting of theoretical courses and laboratory-based practical modules (Mischo, 2015). The possibility of having practical training in real mining conditions on actual mine sites or processing plants is limited, while the only contact that undergraduate students have with mining operations during their time of study is usually through shorttime internships or visits in the context of educational trips. Real integration between universities and the mining industry may be scarce, which does not help students to observe the actual processes and thus understand the whole picture of mining operations.Indirect practical training is now possible since that technology is shifting from mechanical to digital, and the use of virtual reality — in the context of Mining 4.0 — can provide additional experience to the learning process. However, virtual reality is limited to the visual impression and is also limited in actions (Binder et al., 2018). In any case, when there is not a proper pragmatic view of how the different disciplines link to each other, especially if there is a lack of communication, unfortunately the results could be seen at a later stage in the mines as a poor performance of professionals and workers.Another major challenge for educating specialists in the mining sector is that experimental mines suitable for practical education, where the skills and knowhow could be developed and/or enhanced, are rare worldwide. Such research and educational (R&E) facilities are practically former metal ore mines that have been transformed into experimental sites. Besides being limited in number, not all facilities of this kind serve both a research and educational purpose.An early example of asolely experimental mines is the Luossavaara-Kiirunavaara Mine site operated by LKAB in Sweden, where systematic research on rock mechanics and mining engineering was successfully carried out in the 1980s. As a result, the developed underground mining technology was applied in LKAB’s mines at a later stage. There have also been research mines within collieries such as the former Lake Macquarie Mine at New South Wales in Australia and the Zeche Tremonia Mine in Germany), but these are no longer in operation (Mischo, 2015)."

Oct 1, 2019

By Noel N. Moebs

This report summarizes a U.S. Bureau of Mines study on the application of geotechnology to identify and minimize ground control hazards in talc mining operations in northwest Georgia. The major ground control hazard is pillar sloughing attributed to the steeply dipping orientation of a pronounced foliation in the talc ore body. The sloughing problem, which gradually reduces the effective support area of a pillar through attrition, can be minimized by appropriate artificial support, as determined by a rock classification system, and by a more uniform pillar design. A boundary element model confirmed the advantages of using a uniform pillar design to avoid excessive loads on portions of irregular pillars. Instrumentation to measure roof convergence and pillar loading was installed at selected locations in an active talc mine but failed to detect any significant changes, suggesting that the gneiss hanging wall constitutes a strong roof that probably can support large spans between pillars and permit high extraction ratios. This interpretation also is supported by a rock classification of the hanging wall gneiss.

Jan 1, 2010