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By W. H. Schiffbauer

The protection of miners, equipment, and infrastructure is discussed. While the primary focus of the described technology is to prevent miners from being injured, struck-by, or crushed by heavy equipment; another major benefit realized is also the protection of equipment and infrastructure. An attempt is made to define and classify the systems used to provide proximity detection and warnings as well as collision detection and avoidance. Information about the speed of vehicles and human operator response time can be a factor in the choice of what type of system and what features are needed to properly address the needs. How the technology adjusts to compensate for various vehicle speeds, while maintaining the same level of protection is noted. The statistics which justify the need of miner protection are provided. The primary system components required, what attributes they feature, and how they respond in the environment, is briefly highlighted. The physics behind the danger zone marker technology and what makes it so robust and reliable is established. Examples of a few mining applications and specific operational modes are provided for both surface and underground.

Jan 1, 2011

By J. S. Y. Wang, R. C. Trautz

A 9-meter-long drift was constructed in the unsaturated-fractured tuff at Yucca Mountain to evaluate the potential for water seeping into an underground opening. Forty seepage tests were performed by releasing a finite volume of water at a constant rate into short test intervals located in boreholes positioned above the drift. The seepage threshold flux, defined as the liquid-release flux at and below which water will not drip into the opening, was determined for 10 test intervals. The seepage data, observations, and model results indicate that a seepage threshold exists because a capillary barrier diverts water around the opening.

Jan 1, 2000

By A. Norholm

For grinding Portland Cement, the power consumption accounts for some 35 % of the total consumption of electrical energy for producing cement, counting right from the quarry to the packing plant. It is therefore for very good reason that great efforts during the past years have been put into making cement grinding more efficient, thereby saving power. In this paper three ways of reducing the consumption of electrical energy will be described, namely precrushing in the high pressure FLS-Köppern roller press, the introduction of a new design of COMBIDAN diaphragm in ball mills and the separation of mill discharge in the newly developed high efficient; separator SEPAX from F. L. Smidth.

Jan 1, 1987

By H. J. Ilgner

Previous applications for using waste rock for backfilling in South African gold mines were reviewed and it was found that in many cases the mechanical equipment selected and the design philosophy applied did not meet the requirements. A more simplified system configuration is proposed, which allows the equipment to be relocated as mining progresses. Innovative high-intensity grinding and dense-phase pumping technology are proposed to provide a low-porosity backfill with a particle top size of 5 mm to 8 mm. According to recent rock mechanics modeling work, this comminuted waste backfill material can provide a good compromise between underground support characteristics and reliable hydraulic transportation behavior.

Jan 1, 2001

By Richard R. Klimpel

This paper reviews some of the factors involved in selecting amine flotation reagents used to remove silica from ores. A comparison is made between the chemical reagent design approaches used to identify flotation reagents that are used to recover silica- and oxygen-containing minerals and the chemical reagents used to recover sulfide minerals. This introduction gives practitioners who are involved with oxide- and carbonate-type minerals and who may not be familiar with sulfide mineral flotation some ideas of the chemical reagent design challenges that exist with froth flotation on a broader scale and why oxide type mineral flotation reagents are what they are. This is followed by several sections that discuss various classes of available amines. The closing sections emphasize that the optimal choice of an amine collector depends not only on that amine's specific chemical characteristics and costs but also on the operating conditions, especially the flotation feed particle size distribution.

Jan 1, 1999

By G. L. Barthauer

It is a distinct privilege to have the opportunity of addressing this group today. Although I, myself, am not a mining engineer, I have always had profound admiration and respect for those of you who each day live and work according to the tenets of Murphy's Law. Murphy, as some of you may know, was an Irish philosopher whose sole contribution to his field was the observation, "In the mining industry, if anything can possibly go wrong, it will!" You have heard this afternoon a variety of papers, touching on or describing in some detail imminent problems which presently face the coal industry. Many of these problems show no signs of diminishing. Actually, there is good reason to believe that they will intensify as governing bodies pass additional enabling legislation and regulatory agencies adopt more stringent "Rules and Regulations". In many cases, these groups are seemingly oblivious or indifferent to either cost factors or technical problems involved in achieving the desired goals.

Jan 1, 1967

By W. F. Mullen

Within the scope of this discussion, artificial dimension stone is defined as any manufactured product used as a substitute for natural dimension stone. The history of the development of these substitute materials is reviewed briefly, representative characteristics of each product are listed, several analyses of their market position are presented, and suggestions are made for recapturing markets lost to these products and preventing additional inroads.

Jan 1, 1959

By Don Reining

The sand and gravel industry in Southern California has made a sizeable contribution to the construction development of the 15 County area in this part of the State. Facing this mineral extraction industry, in the next decade, is a problem of meeting the market demand. The question is, "how can sand, gravel and rock operations be made compatible with goals for sound and attractive community development?" Three basic principal characteristics of the land needed for this-mining industry are: 1. The land must have workable sand, gravel or stone deposits. 2. The land must be properly located for transportation purposes close to the market in order to sell the aggregate at a minimum cost. 3. The land must be zoned so that it will be permissible to mine.

Jan 1, 1967

By Robert W. Elayer

For the design of a coal mine and process plant, a comprehensive foundation of geologic information is essential. Historically, the development, collation, and use of this information for design have been costly and time consuming. With the application of a digital computer, however, the effort expended can be reduced and maximum effective use of the geologic information realized. The purpose of this paper is to demonstrate the feasibility and convenience of using a computer to Store and manipulate geologic data for use in mine and process plant design.

Jan 1, 1975

By T. Yegulalp, R. Farrauto, A. Belova, M. Castaldi

Calcium oxide, with its ability to capture and store carbon dioxide, is emerging to become an important tool in carbon management. Calcium oxide can be used reversibly to capture carbon dioxide in situ and then be regenerated to produce a pure stream of carbon dioxide ready for sequestration; the Zero Emission Coal Alliance technology utilizes this property of calcium oxide to generate emissions-free electric power from coal. The reaction of calcium oxide with carbon dioxide resulting in thermodynamically stable carbonate is well understood; however, the efficiency of this reaction is limited by the diffusion of gases through bulk calcium oxide and through a layer of carbonate formed on the surface. In addition, the regeneration of calcium oxide is an endothermic reaction and is favored at high temperatures. The purpose of this paper is twofold: first, to address the diffusion limitation, a thin layer of calcium oxide, supported on a high surface area material, is studied thermogravimetrically to demonstrate the physical adsorption of carbon dioxide on calcium oxide. The adsorption is to take place at temperatures lower than required to form calcium carbonate.

Jan 1, 2007

The 25th Peruvian Mining Convention (Convención de Ingeneieros de-Minas del Perú) was held Sept. 10-14, 2001, in Arequipa, Peru. The biennual meeting, sponsored by the Peruvian Institute of Mining Engineers (Instituto de Ingeneiros de Minas del Peru), is designed to showcase the Peruvian mining industry and to ?promote progress in the national mining sector.? The convention consisted of technical sessions, forums, field trips and social activities. The technical sessions featured 80 papers selected from more than 200 papers submitted. The well-organized 2001 meeting was held at the Tecsup Institute of Technology of Arequipa. The meeting was held in conjunction with Exposición Technologica Minera (Extemin), a mining trade exhibition. The2001 Extemin had representatives from more than 400 companies in attendance. In addition to the many Peruvian companies present, the trade exhibition featured pavilions representing the United States, Canada, Germany, Australia and Chile. Registration at the 2001 meeting was about 3,300, a conference record. The theme for the 2001 meeting was Mining: Society and Development. Mario Brescia was chairman of the organizing committee. He said in his opening remarks that ?this year?s meeting seeks to emphasize the commitment on the part of the [mining] companies to treat our natural resources responsibly, controlling any adverse impacts and giving priority to group benefits.? Consistent with this theme, many of the technical papers stressed environmental and social responsibility. Many successful examples of environ-mental and social responsibility on the part of the mining industry were presented in the technical sessions.

Jan 1, 2001

By John Trefny

Although mining is currently one of the smallest academic units on the Colorado School of Mines(CSM) campus, it is alive and well, with nearly 100 undergraduate and graduate students. For many years, Mines has had undergraduate and graduate programs in hard-rock mining. The school has recently transferred its physical mineral processing activities to the Mining Department. The program has also expanded to include tunneling, underground construction and industrial minerals. There are current discussions about increased research activities on cement and other construction materials. The Mining Department also teaches its share of what is called the “distributed core” courses with curricular requirements common to related programs, as well as mining safety and health, in conjunction with our continuing education department.

Jan 1, 2002

By Tim O’Neil

“America’s mining industry brings good jobs to communities across America and provides the energy, minerals and equipment that are vital to our economic security and our way of life.” That was the surprise videotaped greeting from President George Bush at the official opening ceremony of MINExpo 2004in the Las Vegas, NV Convention Center. Jack Gerard reinforced the upbeat mood at MIN-Expo. He praised Nevada Gov. Kenny Guinn for his support of the mining industry, the state’s largest manufacturing sector. Gerard is the president and chief executive officer of the National Mining Association, the sponsor of MINExpo 2004.

Jan 1, 2004

By C. A. Rowland

The use of the Bond Work Index to size industrial grinding equipment is well known. Its use to measure grinding efficiency was presented by C.A. Rowland, Jr. at an AIME meeting in 1976. However, due to a bureaucratic error, the paper was never submitted for publication. This metric has nevertheless been adopted by industry as a widely used standard. The purpose of this paper is to re-present and update the application of this tool as a standard for measuring grinding circuit efficiency. Definition ?standard, n. something established for use as a rule or basis of comparison in measuring or judging capacity, content, extent, value, quality, etc.; as standards of weight and measure? (Webster, 1958).

Jan 1, 2008

By . A. J. Erickson

The Park City District, one of three major mining districts in Utah, is located approximately 20 miles southeast of Salt Lake City on the eastern slope of the Wasatch Mountains. The district has been in near continuous production since 1869. Production has been sustained from exceptionally long bedded replacement ore bodies in the Thaynes, Park City, and Humbug formations and also from several major veins. District production is summarized below. TABLE NO. 1 Park City District, Total Production, 1869 thru 1968 (Source r Various Company Records) [ ]

Jan 1, 1970

By G. Ferrara

Hydrocyclones and other dynamic separators are normally fed with pulps of water and solid particles. The particles have different sizes, shapes and densities and, except in the special case of mono-characteristic particles, are segregated into size, shape and density. Segregation is magnified by the high values of centrifugal acceleration in the hydrocyclones. This paper develops the theory of the segregation, indicates the major variables involved and reports experimental data of segregation under different operating conditions for mixtures of magnetite and/or ferrosilicon and non-magnetic minerals.

Jan 1, 1995

By Brad Murray

Evaluating the performance of a shielded tunnel boring machine (TBM) can be difficult because the ground cannot be observed directly and in relation to the TBM attitude within the excavation. It is difficult to determine whether performance problems are caused by ground loading, steering issues, fine muck packing against the shield, or migration of annular grout around the shield. The Arrowhead Tunnels Project in Southern California uses strain gauges on its shielded hard rock TBMs to detect shield strains early and correlate them with tunneling conditions, thereby increasing the chances that problems will be correctly diagnosed and addressed to optimize TBM performance. The frequent automatic measurement of shield strain has also been valuable by confirming whether remedial methods used to free the machine after stoppages are effective. This paper discusses the qualitative interpretation of characteristic strain patterns on the Arrowhead Tunnels TBM shields and discusses installation details and special considerations for setting up a strain measurement system.

Jan 1, 2008

By Raj K. Rajamani, Poly K. Songfack

The slurry transport within the ball mill greatly influences the mill holdup, residence time, breakage rate, and hence the power draw and the particle size distribution of the mill product. However, residence-time distribution and holdup in industrial mills could not be predicted a priori. Indeed, it is impossible to determine the slurry loading in continuously operating mills by direct measurement, especially in industrial mills. In this paper, the slurry transport problem is solved using the principles of fluid mechanics. First, the motion of the ball charge and its expansion are predicted by a technique called discrete element method. Then the slurry flow through the porous ball charge is tackled with a fluid-flow technique called the marker and cell method. This may be the only numerical technique capable of tracking the slurry- free surface as it fluctuates with the motion of the ball charge. The result is a prediction of the slurry profile in both the radial and axial directions. Hence, it leads to the detailed description of slurry mass and ball charge within the mill. The model predictions are verified with pilot-scale experimental work. This novel approach based on the physics of fluid flow is devoid of any empiricism. It is shown that the holdup of industrial mills at a given feed percent solids can be predicted successfully.

Jan 1, 1995

By T. V. Vasudevan

Floc properties such as density, size, size distribution, porosity, and shear strength govern the effectiveness of flocculation as a process for solid-liquid separation. The floc characteristics desired for removal of suspended solids by sedimentation or filtration, for example, are known to he different. In this study, an attempt has been made to evaluate the effects of various physical and chemical factors on the density and shear strength of the flocs.

Jan 1, 1990

By John Nadolski

Intensive hydrologic monitoring of the Powder river basin has been on-going since the early 1970's. Data were used in environ- mental assessments and for determination of hydrologic consequences associated with coal mining activities. For most coal mine operators, data collection has continued in this baseline mode with little or no statistical analysis of the data and with no statistical procedure established to detect changes in groundwater quality. For the past four years Powder River Coal Company has studied several statistical techniques to analyze groundwater quality. Three objectives were pursued: 1) to determine the baseline water quality for key aquifers; 2) to determine which wells could be deleted from the monitoring program without reducing monitoring effectiveness; and 3) to define a statistical test to determine water quality changes. Knowledge of the regional geo-hydrologic system was combined with an analysis of the water quality monitoring in order to identify homogeneous aquifer zones. All wells within an aquifer zone were treated as one population, and a t-test was used to determine the minimum number of samples needed to define the water quality for each aquifer zone. Results indicate that the data for each aquifer zone were nor- mally distributed and that groundwater quality could be defined using a fairly small number of samples. Because of the minimum sample size test, groundwater quality sampling was reduced by between 75 and 85 percent.

Jan 1, 1989