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By D. Gu

Shaft drilling is one of the most useful methods of driving shafts. This paper describes the application and development of the technique in coal mine construction in China.

Jan 1, 1993

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

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

Jan 1, 2015

By R. S. Conti, M. R. Krump, C. P. Lazzara Ph. D., R. L. Derick, L. L. Chasko

A mine fire is one of the most challenging safety issues facing a mine operator and can occur at any location underground. The National Institute for Occupational Safety and Health (NIOSH) and the Twentymile Coal Mine, CO, conducted in-mine experiments to determine the capability of high-expansion foam for addressing underground fires. The tests were conducted in sloping entries with high-capacity diesel-powered foam generators. The following results were observed: a well-designed, maintained and properly operated high-expansion foam generator can propagate a foam plug hundreds of feet in steep upward-sloping (20%) multiple entries against a ventilation pressure; stoppings and partitions designed to contain the foam plug in upward-sloping entries must be substantially constructed; and the predicted quantity of foam concentrate can be significantly less than the actual amount used, due to foam losses, such as bubble breakage on dry surfaces. This paper describes the production of high-expansion firefighting foam and discusses the in-mine experimental tests and results.

Jan 1, 2010

By Katzer R. Klimpel, J. Sewell

Dr. Roussey Roussev The use of chemical additives on grinding is of significant importance considering the high energy consumption of grinding processes. My research indicates that the dispersant approach explains the effects, in this particular case of wet grinding. Further, the dispersant approach combined with torque measurements give the possibility of clarifying the mechanisms involved when using grinding aids. I find the conclusions derived from the data obtained to be correct and useful for grinding. In general, I agree with the explanations. However, I would like to discuss several additional points that I consider to be important, and in the same time to mention some of my own results from investigations similar to those presented in the study under discussion. The "bed volume concept" and the change of slurry viscosity explain adequately the data plotted on fig. 3, in conjunction with Figs. 1 and 2. However, the significant increase of the average torque in the case of 83% solid with XFS-4272 introduces the necessity of establishing the optimum of percent solid when dispersant is used. For example, the optimum percent of solid for different materials varies. One of the reasons is the material's mass density. On the other hand, it is necessary to determine the concentration of the chemical used. Because of this, it would be interesting to know how the cited concentration was selected. The supportive discussion and verification by Dr. Roussev, with results similar to that of the paper, is appreciated. I will try to answer the additional questions he has raised. To begin with, the mill was fitted with six lifters of approximately one-quarter inch height. There has been extensive lab and plant level work to understand downstream influences of using dispersants like XFS-4272*. In sulfide ore processing, which is the area in which most industrial scale testing has been performed with this approach, neutral to positive influences have been observed. For example, positive effects (e.g., increased recovery) have been noticed in flotation operations involving ores that have a tendency to produce excessive slimes upon grinding. (1) Also, the use of a dispersant has been shown to demonstrate a positive influence on classification by improving the sharpness of separation and preventing a decrease in d50 value that usually accompanies increasing flow rates to classifiers.(2) The biggest potential downstream problem is in thickening, which at the dosages involved, has not been a problem in plant scale usage. The commercial price of dispersants like XFS-4272 is quite variable depending on source, concentration, etc, but a typical cost of XFS-4272 to achieve a 10% increase in throughput in industrial mills has been between 20 and 35- US per ton of feed ore (1981).

Jan 12, 1982

By C. C. Russelll, V. T. McLemore

The Metals Mining Sector of the Acid Drainage Technology Initiative (ADTI-MMS) addresses technical drainage-quality issues related to metal mining and related metallurgical operations, for future and active mines, as well as, for historical mines and mining districts. One of the first projects of ADTI-MMS is to develop a handbook describing the best sampling, monitoring, predicting, mitigating, and modeling of drainage from metal mines, pit lakes and related metallurgical facilities based upon current scientific and engineering practices. One of the important aspects of planning a new mine in today’s regulatory environment is the philosophy of designing a new or existing mine or expansion of operations for ultimate closure. The holistic philosophy taken in the ADTI-MMS handbook maintains that sampling and monitoring programs should be designed to take into account all aspects of the mine-life cycle. Data required for the closure of the operation are obtained throughout the mine-life cycle, from exploration through post-closure.

Jan 1, 2004

By Christian F. Baiz

The author will present a discussion of the steps which must be taken by the prospective developer of a small mining operation to establish technical credibility when seeking financial backing. Particular emphasis will be given to the differing levels of technical work (and their relative cost) which must be accomplished to supply the information necessary to satisfy potential investor groups, whether they be other mining companies, equity investors, or financial institutions such as venture capital firms or commercial banks.

Jan 1, 1981

By N. C. Trivedi

Natural calcium carbonate, commonly known as limestone is an abundant resource pretty much worldwide. Calcium carbonate occurs naturally as the main constituent of chalk, limestone, and marble. One of the unique characteristics of this abundant mineral is its versatility. Major markets for calcium carbonate are: paper, plastics, caulks and sealants, carpet backing, paint, and food additives. This broad spectrum of consuming industries has warranted producers of this industrial mineral to be innovative and quality focused simply to meet the ever increasing demands for performance. This need for improving performance of calcium carbonate has led to the development of new sources of calcium carbonate, natural as well as synthetic.

Jan 1, 2002

By Stephen Njoloma, William Bracken, Harald Cordes, Ivan Hee

"DC Water’s First Street Tunnel (FST) is part of the $2.6 billion Clean Rivers Project designed to reduce the occurrence of combined sewer overflows into local waterways. Due to flood events in the Bloomingdale and LeDroit Park neighborhoods, the FST Project was accelerated by DC Water to mitigate future flooding by boosting storage capacity and thus relieving the undersized combined sewers.The FST Project was finalized in 2016 as a collaborative effort between DC Water, its consulting team consisting of Greeley & Hansen and McMillen Jacobs Associates, and the design-build team of Skanska, Jay Dee Contractors (SKJD) with WSP Parsons Brinckerhoff as the designer.Scope of project. The FST Project (Fig. 1) included four primary shaft sites, a large 6 m (20 ft) internal diameter, 823- m (2,700-ft) long bored tunnel and three adit connections from the off-line shafts to the large-diameter tunnel. The adits which vary in size and length, are the subject of this article. The Channing Street site (Fig. 2) was established as the main site for an Earth pressure balance tunnel boring machine (TBM) and included a 49-m (160-ft) deep shaft with slurry wall support of excavation and 20-m (65-ft) internal diameter final cast-in-place permanent concrete liner. The construction sites at Adams Street, V Street and Thomas Street each consisted of off-line shaft structures tied to near-surface sewer diversion chambers and ventilation facilities. These three off-line shafts were connected to the large bored TBM tunnel via adit tunnels. Each of the three adits had a portion or the entire length excavated by sequential excavation method (SEM) in frozen ground.The Adams Street adit (Fig. 3) was constructed in two phases. The first phase is the 23-m (75-ft) long and 5-m (16-ft) diameter section immediately outside the drop shaft which also serves as the deaeration chamber and was excavated by SEM. The second phase which is 91 m (300 ft) long and 3 m (10 ft) in diameter was excavated by Micro TBM (MTBM) launched from within the permanently lined deaeration chamber. MTBM excavation commenced toward a reception chamber that was excavated by SEM from the previously bored FST TBM tunnel. This SEM excavation had a 5 m (17 ft) diameter and a length of 4.5 m (15 ft)"

Jan 3, 2018

By Vasilis Androulakis, Caroline Gerwig, Zach Agioutantis

Mining operations that involve caving of the overlying strata are designed so that caving occurs in a controlled manner by progressive overburden failure. However, there are many cases where the overlying strata bridge over the caved area for longer periods than anticipated and desired. As the caved area expands with the advance of the mining panel, excessive amounts of energy accumulate in the roof strata which will be rapidly released when the overburden eventually fails.

By E. A. Metz

Work related pulmonary diseases are in the top TEN causes of occupational disability and death in the United States. Likewise, it also ranks high inmost of the other industrial countries. It is difficult to know the true occurrence of occupational lung disease because of poor documentation. This is especially true when one examines workers’ compensation claims. Most frequently, silica and asbestos are paramount in our discussion of work related pulmonary disease. Little consideration is given to other “dust-related” diseases, irritant reactions, reactive airway responses, and hypersensitivity reactions. The major classification of occupational lung diseases will be discussed. This includes both acute and chronic disease that arises in the work place, especially, the mining industry. It’s more important to make an accurate evaluation and diagnosis for the prevention of disease among other workers.

Jan 1, 2000

By G. T. Lineberry, L. Adler

Due to safety-imposed constraints on clearances for mobile bulk handling equipment, it is necessary to optimally select a unit based on speed and size. The unit cannot be both large and fast. Since output is proportional to both size (or capacity) and speed, the combination must be carefully examined to maximize output. A simple graphical procedure and a calculus-based solution are presented to accomplish this. While the procedure applies to all mobile bulk handlers, as an example of the solution technique, attention is focused on shuttle cars. Background Major variables To fully define a bulk handling problem, the conditions, equipment, and activities must be characterized. The conditions and activities, when lumped together, are termed "encumbered space," since they "act to impede motion, as with a burden" (Lineberry, 1979). The insertion of mobile bulk handling equipment into what is already a difficult set of conditions and activities compounds the state of encumbrance, as limited space is competed for by many normal and life support systems. Long (1972) recognized the effects of design criteria, including road width, on haulage vehicle speed and, therefore, on production. Velocity -clearance curves Velocity-clearance curves are either available or can be constructed in the field. A preliminary set of curves for average conditions and activities is shown in Fig. 1, where clearances are only for the side of the vehicle (Lineberry and Adler, 1984). These curves set the safe speed limits for a vehicle operating at given clearances, under given conditions and activities. When feasible, velocity-clearance curves should be constructed through field measurement and observation. Curve construction should also consider haulway roughness, distances, and operator skill, as well as loading and dumping characteristics. It should be noted that haulage capacity determination is a total systems problem, not one just dependent on velocity and clearances. Production requirements and company capabilities also influence capacity determination.

Jan 10, 1985

By M. L. Chapman

When originally accepting the assignment, the Client had described the property as vacant land. A prior appraisal was later discovered and revealed that the property included a mineral rights appraisal. Further research disclosed an old dispute with a court ruling based on testimony by AIMA-certified experts. The present appraisal was therefore based on data from findings of the court with a fresh look at discount rate, absorption period, and residual land value. Fortuitously, the property subsequently sold on the market, while meeting all criteria for Fair Market Value. This provided insight into a market-based discount rate. Also, the absorption period could be adjusted in accordance with the current market conditions. The residual land value was minimal (based on comparable sales and projecting trends in market) as the property was affected by a flood zone and the surrounding development was sparse. PROPERTY HISTORY: A GREAT INVESTMENT Briefly, the subject property is located in the floodplain region of the San Jacinto River, a short river in southeastern Texas that flows into Galveston Bay, filled with sand and gravel. This location is on the north side of Houston, north of Beltway 8 on the east side of I-59.

Jan 1, 2012

By B. Boberg

Annual requirements of uranium to fuel the 441 currently operating nuclear reactors in the world is 170 million pounds U3O8 (65,385 tonnes U). 2005 global production was 108 million pounds (41,595 t U), of which only 2.7 million pounds U3O8 (1,039 t U), was produced from US uranium deposits. US nuclear utilities represent 26% of the global nuclear capacity but only obtain 2.5% of their supply from US uranium mines. Since 2002 annual global production increased from 93 million pounds U3O8, a 15% increase and the US production increased from 2.3 million pounds to 2.7 million pounds, a 17% increase. Reasonably Assured Resources (RAR) of 12,332 million pounds U3O8 (4.7 million t U) are reported from a wide variety of countries and types of uranium deposits. This RAR suggests that there are significant global uranium resources potentially producible at a price of $50 per pound U3O8 ($130 per kg U). Table 1 shows the distribution of global uranium resources. This table, prepared from historic data maintained by the World Nuclear Association, does not include some areas of the world that are currently considered to contain significant resources of uranium such as Mongolia. Table 1 suggests that the United States contains the fourth largest uranium resource in the world with 890 million pounds U3O8, behind Australia, Kazakhstan and Canada in resources that are producible at a price of $50 per pound U3O8 ($130 per kg U). Within the US, the states that demonstrate the greatest amount of uranium resource are Wyoming, New Mexico, Texas and the Four Corners Area of Arizona, Colorado and Utah.

Jan 1, 2007

By P. A. Plunkert

Metallurgical-grade bauxite was imported into the United States from 11 countries in 2004. The principal suppliers of this 10 Mt (11 million st) of imported ore were Jamaica (33 percent), Brazil (25 percent), Guinea(23 percent) and Guyana (11 percent). The average value of imports, cost, insurance and freight (c.i.f.) U.S. ports, was $31/t ($28/st). Calcined refractory-grade bauxite imports were 165kt (182,000 st) with an average value of $146/t ($132/st), c.i.f. U.S. ports. China supplied 70 percent; Guyana, 22

Jan 1, 2005

By L. Mead

Dimension stone is a natural stone (granite, marble, limestone, sandstone and slate) that can be quarried, cut and shaped to conform to acceptable industry standards for size, consistency and durability. There are numerous outlets for the finished product in exterior and interior architectural and design applications. A continued growth market is with residential usage— particularly in new, upscale construction. This has become a competitive market between domestic producers and lower cost imported products. These imported products have become available at many of the building supply retail outlets and have increased the use of stone in residential construction and renovation. The traditional architectural application of dimension stone is tied to commercial and institutional building construction trends and market. There has been a noticeable increased usage of stone in the Sun Belt. This stone is usually supplied by local fabricating shops. It is used in the exterior and interior of shopping malls. This market generally uses local stone sources. It has increased the demand for sandstone, limestone and quartzite in this region of the country.

Jan 1, 2005

By Frederick A. Mumpton

Recent findings by medical workers on the association of certain zeolite minerals with the high incidence of pleural mesothelioma in two small Turkish villages have caused considerable excitement both in medical circles and in the synthetic and natural zeolite businesses. The 42 cases diagnosed between 1970 and 1977 in one community of 600 population in a region of altered volcanic tuff represent a virtual epidemic of this rare malignancy which normally strikes only about one person in a million. Cancer workers around the world expect that detailed environmental and epidemiological studies of the disease in these areas will shed considerable light on the cause of this particularly lethal form of lung cancer. Scientists and engineers developing uses for zeolite materials in industry and agriculture, however, are justly concerned that the preliminary results available on this situation will be used by environmental and regulatory organizations to label an entire group of miner- als as carcinogens on the basis of what is little more than circumstantial evidence. Although there is no question as to the large number of cases of mesothelioma in these areas of central Anatolia, the work to date has suffered from a lack of sound geological and mineralogical input. Ataman (1) stated that a "correlation" exists between mesothelioma and zeolites in this region; however, the geological data needed to document a direct relationship between the presence of zeolites in the volcanic tuffs surrounding the villages in question and the rate of malignant lung disease in the inhabitants have g been obtained, nor has evidence that suggests a cause-effect relationship between zeolites and cancer been reported. To provide fundamental information on the distribution of zeolite minerals in areas of central Turkey where high incidences of pleural mesothelioma have been reported and to evaluate from first-hand knowledge the published reports and news releases of medical workers engaged in assessing the problem, the following investigation was made.

Jan 1, 1979

By C. R. Hairfield

With ever rising energy costs, it is increasingly important for mines to operate with energy efficiency. As a large portion of a mine?s energy consumption is often attributed to the operation of mine ventilation fans, maintaining an efficient ventilation system is a critical pro-active way for mining companies to reduce power costs. A common way to measure a mine?s ventilation system efficiency is to calculate the volumetric efficiency, which is simply a calculation of the percentage of total mine air that is usefully employed for production. The purpose of this study is to document a nationwide comparison of the volumetric efficiency of U.S. underground coal mining operations. The results will aim to show just how efficient today?s coal mine ventilation systems are and what factors may be causing their various efficiencies and inefficiencies.

Jan 1, 2009

By W. Hustrulid

"In recognition of his inspiring dedication to the mining industry through education, research contributions and dissemination of practical knowledge, exceptional leadership and excellence in mining engineering practice and for his lecture, “You can't make a silk purse out of a sow's ear.” Recipient of the 2002 D.C. Jackling Award Introduction It is always difficult to decide on the most appropriate title to give to a paper or talk. It is a particularly difficult decision in the case of the Jackling Lecture, because the title becomes part of the award citation. I hope that the significance of this unusual title will become crystal clear as you read the pages that follow. However, to assist you in this journey, I will provide the following few words of guidance. In making a cake, you need the proper ingredients. If one or more of them are missing, it will not be a cake. In addition, the quality of the cake depends on the quality of the ingredients. In my lecture, the "cake" is the U.S. mining industry of the future. A national perspective President George W. Bush in his State of the Union Address (Bush, 2002) delivered on January 29, 2002, defined three national objectives: •win the war on terrorism, •protect the homeland and •revitalize the economy. Under the heading "revitalize the economy," he indicated the importance of "good jobs" and "energy production" by saying: "Good jobs begin with good schools. Good jobs also depend on reliable and affordable energy. This Congress must act to encourage conservation, promote technology, build infrastructure and it must act to increase energy production at home so America is less dependent on foreign oil." I wish that he would have broadened his focus and stated instead that: "This Congress must act to encourage conservation, promote technology, build infrastructure, and it must act to increase materials production at home so America is less dependent on foreign sources." With regard to jobs, all jobs are not equal. To paraphrase John Reeves of MidContinent Resources (Reeves, 2002): "If our nation is to prosper, we all cannot make a living by doing each other's wash. Some of us, at least, must be actively engaged in the primary production of raw materials from the riches of the earth and other Americans must turn those materials into consumer products." The unfortunate trend in our country has been to neglect the primary production of basic materials, even those coming next in line. We have left those responsibilities to others while we concentrate instead on performing various services, i.e., doing each other's wash and flipping burgers. This cannot continue. It must be remembered, especially by those in leadership positions, that all "jobs" are not created equal. Some jobs are much more essential to the security and wellbeing of our country than others. We must be sure that the important ones are in place. We cannot produce the basic materials that our nation requires without access to those materials. This leads to my Proposition 1: You cannot have a viable mining industry without a clearly enunciated, positive U.S. materials policy. Background regarding U.S. materials policy Resources for freedom. In January 1951, President Truman created the President's Materials Policy Commission, with William S. Paley as chairman. As expressed in the invitation letter from the president to Paley: This commission, within the executive office of the president, is to study the broader and longer-range aspects of the nation's materials problems as distinct from the immediate defense needs. The task of the commission is to make an objective inquiry into all major aspects of the problem of assuring an adequate supply of production materials for our long-range needs and to make recommendations that will assist me in formulating a comprehensive policy on such materials. The commission should study, together with any other aspects deemed by it to be pertinent, such questions relating to production materials as: - the long-range requirements outlook; - the long-range supply outlook; - the prospect and estimated extent of shortages; - the consistency and adequacy of existing government policies, plans and programs; and - the consistency and adequacy of private industry practices.

Jan 1, 2003

By P. Mills

The four top barite-producing countries in the world are China, India, Morocco and the United States. China is currently the largest exporter of barite followed by India. More than 95 percent of the barite mined today is used by the petroleum industry as driller’s mud. The rest is used in the industrial market and the medical field. Most of the barite mined in the United States is in Nevada. This year, mining activity has increased due to an increase in oil exploration/development. This was caused by an increase in the crude oil prices.

Jan 1, 2005

By R. P. Proulx

The Meikle Mine is a high grade, underground goldmine utilizing primary-secondary longhole open stoping with delayed backfill to produce 2700 tpd(3000 stpd) of ore. Hot and reactive ground conditions were encountered early on in the mine life. Ground temperatures up to 166°C (330°F) were measured. In the early stages of mining, the mine experienced premature detonations using different explosive products. The learning curve to safely mine this high-grade gold deposit in hot and severely reactive ground was indeed very steep. Currently, the Meikle Mine uses a special buffered bulk emulsion in all blasts to address hot and reactive ground concerns. In addition, exacting procedures are also followed to ensure safe work with explosives. The combination of new explosives technology and strict loading procedures permits high mine productivity with the highest degree of safety.

Jan 1, 2000