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By I. Toromanoff, F. Habashi

The transformation of a low-grade titanium slag into synthetic rutile or synthetic anatase can be enhanced by attrition grinding.

Jan 1, 1987

By D. V. Ramani, M. M. Kissel, M. T. Ityokumbul

Experiments were carried out to determine the efficacy of bubble column flocculation. An acid-base neutralization method was used to determine the mixing time in a 0.064- by 1.5-m bubble column equipped with a Mottporous sparger. The mixing times decreased as the tracer injection point approached the gas sparger. Preliminary flocculation experiments on two clay samples were carried out. The effects of frother addition and airflow rate are presented and discussed.

Jan 1, 2000

By A. B. Szwilski

The mineability and coal processing costs are influenced largely by the structural and physical properties of the coal seam. The mining process involves coal cutting, pillar support, crushing, and floating. A correlation between the rank, ash content, and coal strength/stiffness is discussed. The coefficient of variability of rebound tests on the face of various coal seams are compared with those of laboratory compressive strength tests by other investigators.

Jan 1, 1988

By Albert E. Ketler

The techniques for fire monitoring of conveyor belts in underground coal mines have been revolutionized by the advent of sensitive carbon monoxide sensors and computer monitoring systems. These new systems are rapidly replacing the previous thermal (fixed-point temperature) sensors that have been shown to be considerably less sensitive for early fire warning. CO is generally an excellent indicator of spontaneous combustion. However, the most recent non-flammable conveyor belt materials have been shown to "burn" with dense smoke, but without sufficiently high temperatures to produce much carbon monoxide. To cover this fire detection void, a smoke detector was developed to augment CO sensing for these new conveyor materials. However, computer monitoring provides the flexibility for handling this and other additional instrumentation as fire monitoring techniques evolve. CO, smoke and temperature sensing may eventually be advocated for complete fire monitoring.

Jan 1, 1987

After a discussion of the principles of heavy-mineral enrichment and the sedimentary history of shelf sediments, four models are described that can explain the genesis of heavy-mineral deposits in shelf areas. On the basis of these models, the heavy-mineral potential of most shelf areas is estimated to he significantly lower than the potential of their neighboring coastal plains.

Jan 1, 1991

By E. Varouchakis

Spartan Spatial Random Fields (SSRF?s) provide a new geostatistical framework (Hristopulos, 2003) with applications targeting environmental risk assessment and natural resources estimation. SSRF?s have the ability to incorporate constraints based on physical laws in the statistical description and have proved to be computationally fast in the analysis of synthetic data sets. This paper presents an application of a specific SSRF model and a new local-error spatial estimator (Hristopulos, 2005) in the mapping of environmental pollutants using a real data set. A detailed comparison of the local SSRF estimator with a classical kriging method is presented. It is shown that the SSRF approach provides a competitive alternative for spatial estimation.

Jan 1, 2005

By S. Michael Feroz, Michael J. Britch, Frank S. Buehler

The City of Portland is constructing the Columbia Slough Consolidation Conduit as a part of its commitment to reduce combined sewer overflows into the Willamette River and the Columbia Slough. Known as “The Big Pipe,” the conduit has a 3.7 m. (12 ft.) internal diameter and is 5,640 m. (18,500 ft.) long. Construction Segment 1 of the project includes 250 m. (814 ft.) of reinforced concrete pipe (RCP) installed by boring and jacking. Five separate crossings were constructed beneath Union Pacific Railroad tracks and Columbia Boulevard, an adjacent arterial roadway. This paper describes the design and construction of these bored and jacked crossings.

Jan 1, 1999

By Shijie Wang

The metals of value in tetrahedrite are copper, antimony and silver. A new hydrometallurgical process is proposed to recover these metals from tetrahedrite. The process consists of leaching concentrate with ferric fluoborate, solvent extraction, electrowinning and residue treatment. Products from this process are high-purity SX-EW copper and antimony and a high-grade silver residue that will be further treated in a hydrometallurgical process for early release of silver. The process has advantages, such as achieving rapid leaching rates at modest temperatures with high metal recovery. Most pyrite is not attacked. Thus, it remains in the leach residue along with elemental sulfur.

Jan 1, 2003

By Jianguo Hao, Qingbiao Zhao, Bingnan Hu, Shimin Fan

The paper makes a systematic analysis of interaction between backfill and pillar in coal mining. It compares the difference of pillar strength with backfill and without backfill. It is proved that there are the obvious improvements in pillar strength and the decrease in subsidence. It discusses the subsidence effects of different extraction ratio, different backfill ratio, and different elastic modulus ratio in details. The paper analyses the sensitivity by orthogonal test method. At last, author proposes some suggestion to increase pillar strength, to reduce subsidence, and to guide engineering practices.

Jan 1, 2001

By A. D. Shuloyakov, V. A. Zukerman, G. A. Finkelstein, V. I. Kurets

Possibilities of electric pulse disintegration are discussed with emphasis on high selectivity of the process as compared to mechanical comminution methods especially when applied to polymineral ores. Physical explanation of this phenomenon is suggested. The authors present results of some experimental tests illustrating regularity of this phenomenon irrespective of origin of ores or dissemination pattern of valuable minerals including both dissipated and accessory minerals. Some operating plants applying this principle are described the plants used either for mineral research purposes or for obtaining pure monomineral fractions or for treatment of gems to be faceted. Obstacles for implementation of this technology are mentioned.

Jan 1, 1995

By R. Krishna, L. A. Kumar

The paper suggests a new empirical model for predicting mining subsidence. The parameters considered are Lithological Factor, which in this context meant percentage of sandstone, Rock Mass Factor (depending upon the RQD value of drill-hole cores), width: depth ratio and percentage extraction of coal. More than 250 drill-hole cores from seven longwall panels and 11 bord-and pillar (room-and-pillar) workings were analyzed from an extensive data bank of Singareni Collieries Company Ltd. (S.C.Co.), Andhra Pradesh, India. Excellent subsidence agreement was found with the suggested model.

Jan 1, 1993

By Thomas S. Kovach

In today's competitive energy market, every effort must be made to assure the lowest possible production cost. 'rhi s. paper describes the cooperative effort between the coal producer and the utility customer to develop and install a fully integrated mine information management system at a 2.5 million tpy lignite mine in east Texas. A description of each item of the modules is included along with the problems encountered during development and how they were corrected. The system configuration is also described.

Jan 1, 1989

By Y. Nan

A new computer simulation model for the analysis of underground coal mine production systems in the Peoples Republic of China is presented. As a case study the model was used to analyse the railway system of an existing underground coal mine. Some results of this first application are given in this paper and some conclusions of common interest for underground rail haulage systems are discussed.

Jan 1, 1986

By A. A. Mular

Examining a typical curriculum for mineral process engineers shows that traditional subjects remain important, namely, engineering, earth and basic sciences, mathematics and mineral proc¬essing technology. However, Table I shows additional subjects that may be woven into a modern curriculum, because of micro- and macro-engineering advances over the years. The ways to incorporate these subjects into the curriculum will vary from school to school. Such changes are in response to evolutionary technological and political needs as determined by society and business. Beginning with the 1950s, engineering empiricism was strengthened through micro-engineering, where fundamentals and mechanism serve as foundations. Scientific apparatus unique to the basic sciences (Zeta meter, FTIR spectroscope) was adapted to test new hypotheses. Coincidentally, as computers became more available, complex differential

Jan 1, 1992

By D. W. Olson

Estimated world production of natural and synthetic industrial diamond was about 630 million carats in 2004. Natural industrial diamond deposits have been found in more than 35 countries, and synthetic industrial diamond is produced in at least 10 countries. About 80 percent of the global output was produced in Ireland, Japan, Russia, South Africa and the United States. Russia and the United States are the world’s leading producers of synthetic industrial diamond. In 2004, the two U.S. synthetic producers, one in Pennsylvania and the other in Ohio, had an estimated output of 250million carats. Also in 2004, nine U.S. firms manufactured polycrystalline diamond (PCD) from synthetic diamond grit and powder.

Jan 1, 2005

By R. Hogg, T. F. Dumm, L. G. Austin

The applicability of SEM/EDS techniques to particle-by-particle analysis of respirable coal dust is evaluated. It is demonstrated that the correction procedures needed to account for the failure of most EDS systems to detect light elements (especially carbon) become unreliable for particles in the respirable size range (< 10 µm). Other serious limitations arise from x-ray counting errors for coal particles with low but significant mineral content and particle counting errors for liberated mineral matter.

Jan 1, 1991

By D. D. Harbuck

The US Bureau of Mines investigated germanium and gallium extraction from an ore containing 0.089% Ge and 0.036% Ga. While previous researchers concluded that a reducing agent, such as SO2 is needed to extract germanium and gallium from such ore, this research showed that high extractions (87% Ge, 97% Ga) were possible using sulfuric acid alone, if the acid concentration were properly controlled. This control was achieved using a two-stage countercurrent leach circuit. Microprobe analyses revealed that the non-extracted germanium is in solid solution with quartz, and therefore cannot be leached with SO2 or sulfuric acid.

Jan 1, 1991

By F. Wendling, J. A. M. Cano

To increase its product competitiveness in the foreign market, Samarco Mineracão S/A has developed, at its pilot plant, high-MgO pellets for performing direct reduction simulation tests. Additives, such as dolomitic lime and magnesite, were used for increasing the pellet MgO content. Comparative direct-reduction simulation tests were conducted in Samarco and foreign laboratories. The results show that direct-reduction pellets with satisfactory metallurgical properties can be produced and successfully processed at increased temperatures in direct reduction furnaces.

Jan 1, 1994

By Clement K. Chase, George M. Potter

Copper dump and heap leaching operations are conducted worldwide for production of substantial amounts of copper Such dumps and heaps contain appreciable amounts of other potentially valuable elements such as gold, Iron, magnesium, manganese, molybdenum, silver, titanium, and uranium. Except for uranium, recovery of these elements has not been attempted to any significant extent However, such recovery merits attention based upon availability of existing chemical techniques. This paper presents some thoughts on possible techniques together with opportunities for commercial applications.

Jan 1, 1983

Maptek I-Site laser scanning expertise and software technology is being used to map the geology and layout of the deepest underground laboratory to be established in the U.S. The Deep Underground Science and Engineering Lab (DUSEL) in the former Homestake gold mine in Lead, SD, will provide for scientific studies in particle and nuclear physics, geology, hydrology, geo-engineering, biology and biochemistry. The project, funded by the National Science Foun¬dation (NSF), will allow geoscientists and engineers to research the behavior of subsurface rock, minerals, water and energy sources

Jan 1, 2010