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By R. J. Sweigard

One of the foremost problems in reclaiming prime farmland is compaction of the subsoil which is caused by the reclamation equipment. Wheel tractor-scrapers are most commonly used to replace subsoil and have been blamed for the majority of the compaction problems. Two methods of alleviating this problem that are presently being considered are mechanical subsoil loosening machines and truck- shovel combinations for subsoil handling. A field study was conducted in which dry bulk density measurements were taken in an effort to determine the effectiveness of truck-shovel combinations and subsoil loosening equipment in reducing bulk density in comparison to typical scraper replacement.

Jan 1, 1987

By David R. Cole

Before discussing some of the specific public relations issues in Colorado mining, I would like to define public relations, identify the "publics," review Colorado's population profile, and outline Colorado's mining history. Public Relations In describing public relations, a definition which is frequently quoted appeared in the PUBLIC RELATIONS NEWS, and is as follows: "The Management function which evaluates public attitudes, identifies the policies and procedures of an individual or organization with the public interest, and executes a program of action to earn public understanding and acceptance..' As you can see, this covers a "multitude of sins."

Jan 1, 1975

By Susumu Ukita

We have developed first a conveyor belt for transporting large lumps, i.e. Rock Belt successfully, in June 1976. The First Rock Belt had been delivered to Myodani site of Kobe City Developing Board in Japan, and its' successful operation has attract keen interests in customers from over the world as well as Japan. However, this First Rock Belt was removed in arch '81, viewing it has satisfactory expired its service life of about five-year, and also original location of this belt become to be far from the site due to long-years earth collecting work. Taking this opportunity, we introduce the Second Rock Belt applied for Rock Belt Loader as ell as three types of application of our Rock Belt working for rationalization of quarry of major company in Japan, and, view the prospect of Rock Belt:

Jan 1, 1981

By J. D. McAuliffe

The Homer-Wauseca Mine is operated by the Hanna Mining Company, three miles north of Iron River, Michigan on the Menominee Iron Range. The mine produces 5,300 tons of direct shipping iron ore daily. The present main producing level is at a depth of 1,500 feet below the collar. The ore body continues to a depth of 2,700 feet below the collar, to which depth the modern circular concrete shaft has been completed. A view of the property is shown in Figure #1. This paper is a report on the development of large underground boreholes used initially to conduct stope filling material into inaccessible, mined-out stopes. Later holes were drilled for ventilation raises, for mine drainage, for passageway for power cable, also for the primary breaking point for long hole stoping. Some, which were drilled as ventilation raises, were later stripped to a suitable size for a manway or ladder road. The holes varied in size from 6" to 30" with the present popular, economical working size being 16 1/4", used as a stope fill passage in mined out areas and for ventilation in deeper development. Foremost has been the desire to develop equipment suitable for drilling raises large enough for manways.

Jan 1, 1963

By B. Seymour

The National Institute for Occupational Safety and Health (NIOSH) is conducting research to develop safe practices for the use of shotcrete as ground support in underground mines, particularly mines operating in weak host rock. As part of this research, tests were conducted with a commercial poly-fiber reinforced shotcrete mix to develop a practical means of measuring shotcrete adhesion strength. Full-scale tests were conducted in a test frame equipped with concrete panels having three distinct surface roughness profiles. Adhesion test fixtures either embedded or epoxied in the shotcrete were overcored into the underlying concrete, and direct tensile tests were conducted to determine the bond strength of the shotcrete cores to the substrate after a selected shotcrete curing interval (1, 3, 7, 14, 28, or 90 days). Measured adhesion strengths typically ranged from 0.5 to 2.0 MPa depending on the curing age of the shotcrete samples. This paper presents the results of these tests, describes the portable test system components, and addresses some of the design issues encountered in the development of a rugged and reliable method for determining shotcrete adhesion strength in underground mines.

Jan 1, 2010

By Andrew Torok

Activated bleaching clays, so called because of their ability to remove color bodies from bleach fats and oils, are produced from clays of bentonitic origin. Activation is achieved by subjecting these clays to physical or chemical alteration to increase selective sorption capacities (1) . The future of activated bleaching clays depends upon the ability of producers to recognize the new areas of applications which are arising, and their skill in developing sophisticated active clays to meet new and stringent requirements. The major portion of activated bentonites are produced for decolorization of oils. New techniques of activation will improve these clays for broader spectrum use. General properties expected to result from present activation methods are: 1. Modification of hydrophobic-hydrophilic properties and increased available surface area in non-aqueous systems, thereby improving sorption capacity and ability to remove color bodies from oils. The following additional properties will be expected from future activated clays: 2. High purity of the active clay with interfering impurities totally removed. 3. Increased selective sorption capacity in aqueous systems. 4. Selective chemical reactivity, such as oxidation or hydrolysis. This property is required for removing

Jan 1, 1971

By G. R. Doubek

Dual Tube Reverse Circulation (DTRC) drilling has been extensively used for collecting groundwater information for the dewatering program at Amax Gold Inc. Sleeper Mine. This paper presents a discuss ion of the types of data which can be collected from DTRC drilling, as well as the effect submergence has on the data. A simple low-cost method of injection testing has been developed using DTRC equipment, allowing quantitative data to be obtained from exploration or test holes. Potential yields can be determined for each drill location, allowing siting and design of production wells to be optimized.

Jan 1, 1992

By Norman Weiss

The design of an ore-processing plant requires a high degree of cooperation among the geological, mining and metallurgical engineers. The purposes of this section are to provide mill design information most commonly needed by the mine planners and management, and to summarize the kinds of information that must be supplied to the mill designer to enable him to provide a suitable plant. 28.1-BASIS OF DESIGN NORMAN WEISS 28.1.1-SIZE OF PROJECT The size of the project generally is expressed in tons of ore milled per day, but company policies differ widely in this respect, a few adhering to this set figure but many expecting the design capacity to be liberal. To some companies that follow the latter practice a 25,000-tpd milling plant that cannot reach 30,000 or 35,000 tpd without major additions is a disappointment. The engineers responsible for planning the operation must know what is intended. Equally important are operating schedules, particularly the number of operating days per week and shifts per day for ore delivery, crushing, grinding and processing. Hours per shift also are an important factor in design, particularly in the case of ore delivery, and the percentage lost time expected for maintenance, cleanup, inspection, preventive maintenance shutdowns, and many others, has to be taken into account. Frequently, the ore deposit will vary in hardness and grade to such a degree that the capacity of the mill will vary widely from year to year and cannot be expressed as a fixed figure. but rather as an average over a calculable period, such as 10 yr, or as a specific daily capacity over the first 2 yr, next 4 yr, etc., or some similar projection. A good example of this kind of situation is Asarco's Mission operation 15 mi southwest of Tucson, Ariz., described by Weiss and Vincent.' where the major rock types differed widely in hardness, so that a change in the proportion of these types in the mill feed could have imposed difficult design problems if a constant tonnage rate had been expected. 28.1.2-EXPECTED LIFE The life of a mining operation depends upon the size of the deposit and the rate of mining. The latter is a policy decision based on an economic analysis which, in turn, is based on many factors.' From the point of view of mill planning, the estimated life of the operation determines many criteria and affects many decisions on strength of structures and degree of protection of men and materials, the quality of the materials-handling and process machinery, the type of delivery systems for ore to the mill and concentrates to the smelter or market, and many others. Costly installations that may be excellent investments for a 20-yr project may be wasteful for a 5-yr operation. An example is the comparison of different methods of crushing or grinding. Take single- vs. multiple-stage grinding-the former may be found more economical for a 5-yr operation, and the other, more costly, method more economical for a 15 to 20-vi- life.

Jan 1, 1973

By K. Hanumantha Rao, K. S. E. Forssberg, H. R. Manouchehri

This paper summarizes the practical considerations of the various electrical separation methods used in mineral processing. The effective factors related to mineral characteristics and equipment attributes are described and analyzed with reference to conventional industrial applications of the electrical methods. Some new aspects of electrical methods application and their potential for mineral beneficiation, apart from the mineral systems that have been successfully beneficiated, are also presented. In addition, wet dielectric separation, which now appears to be promising, is briefly cited.

Jan 1, 2000

By J. LeRoy Peterson

This paper presents some of the theoretical aspects as well as some results of actual plant operation of the Ty-Hukki Classifier. Dual classification steps within a unit vessel are achieved by controlled separation of the sand product under turbulant flow conditions, followed by further classification under strictly laminar flow conditions. Plant operation has shown some of the benefits of the superior sharpness of classification to be reduction of circulating load in grinding circuits, prevention of overgrinding, increase in mill feed rate and consequent reduction in cost per ton of ore.

Jan 1, 1966

By T. D. Oulton

The only known attapulgite clay deposits of any considerable extent and purity in the United States are roughly bisected by the Georgia. Florida state line between Decatur County, southwest Georgia, and Gadsden County, northwest Florida. Although attapulgite clay occurrences both farther East and South are known and have been mined to some extent in the past, at the present time it can be said that substantially: all of the commercial attapulgite clay mining and pro¬cessing is concentrated in a roughly rectangular area some 25 miles long by 15 miles wide,, in the general region of Attapulgus, Georgia, and of Quincy and Havana, Florida. Within this area are located the clay processing plants of the four major producers as well as most, if not all, of the currently active mining operations. The approximate location of the plants and of some of the open mines are shown in the local area map, Figure No. 1, for the purpose of orientation only.

Jan 1, 1965

By Daniel C. McLean

Chemistry plays a more important role in milling operations than is generally recognized, particularly in fluid- solid separation processes. Chemical aspects are also very important insofar as plant water quality is concerned, and in the manner in which this water quality effects plant design and operation. Aside from the inherent chemical characteristics of plant water, the mineral preparation industry is becoming increasingly more dependent on the use of mining chemical reagents--relatively new to the coal industry, but items of I standard usage in complex metal recovery plants. These chemicals have many useful properties and can produce significant improvements in operations and metallurgical efficiencies when used properly and intelligently. They can produce poor results and sometimes severe losses when used improperly. Most reagents are relatively expensive on a per pound basis, hence costs can be excessive if they are used wastefully or inefficiently.

Jan 1, 1968

By Robert J. Greaves

High-resolution seismic reflection profiling can be used to evaluate detailed struc¬tural and stratigraphic features of coal pros¬pects. Since most coal prospects are relatively shallow (less than six hundred meters deep), the vertical and lateral resolution of seismic data can be significantly improved by high sampling rates in space and time. The case study present¬ed shows the effective use of seismic data in evaluation of the Wyodak coal at a prospective coal gasification site. The data were used to map the detailed structure and thickness of the coal and to search for lateral discontinuities, such as pinchouts and. faults. An important find was a paleochannel cutting across the base of the coal seam, which was later confirmed by drilling.

Jan 1, 1983

By Yi Luo

Bolting the mine roof is one of the noisiest underground mining operations. The main contribution to the high noise is the drilling of the roof bolt holes, especially in hard rock. A previous research shows that the specific energy consumed in drilling the bolt holes is inversely proportional to the bite depth (i.e., penetration per drill revolution). Less specific energy at a reasonably high bite depth means less energy is wasted in the drilling process to produce heat, bit wear and noise. Therefore, control of drilling operation to achieve a higher bite depth can provide an opportunity to reduce drilling noise from its sources as a proactive noise control approach. In order to explore the feasibility and to develop the proactive technology for reducing drilling noise, drilling tests have been conducted in laboratory settings. The preliminary results show significant reduction in noise dose can be achieved by drilling in medium hard rock at a reasonably high bite depth. This paper presents the findings from the laboratory experimental studies conducted so far.

Jan 1, 2013

By Aurel Goodwin

Remarks of Aurel Goodwin, Chief, Division of Health, Metal and Nonmetal Mine Safety and Health, Mine Safety and fEealth Administration, U. S. Department of Labor, before the Society of Mining Engineers of the AIME, Littleton, Colorado, on October 18, 1979. I appreciate this opportunity to speak before the Society of Mining Engineers of the AIME. The topic of my presentation is the Mine Safety and Health Administrations's (MSHA) concern and obligations with regard to asbestiform minerals. Asbestiform minerals - the magical group of hydrated, silicate minerals which possess a fiber like structure capable of being woven, like and into cloth. Their unique combination of properties, such as resistance to heat and chemical attack, high tensile strength, and flexibility was recognized centuries before Christ. Pausanias, the early Greek geographer, speaks of golden lamps made about 430 B.C. with incombustible wicks of "Carpathian flax." The Romans used asbestos as cremation clothes to conserve the ashes of deceased persons of rank. Charlemagne had an asbestos table cloth that he used to pass through fire to clean (1). Early recognition of the health hazards associated with exposure to asbestos was documented in the first century by Pliny the Elder, a Roman naturalist, and Strabo, a Greek geographer. Bath wrote of slaves with sickness of the lungs, whose occupation was that of weaving asbestos into cloth. This concern for the health of asbestos workers disappeared over the ages.

Jan 1, 1979

By Eric Ohl

Due to the world's ever increasing minerals and energy demands, process plants have to cope economically with ever growing throughput rates. This trend has accelerated the development of high capacity vibrating screens. Screens with screening areas of 30 to 50 square meter (322 to 540 square feet) and width of 5.5 meter (18') are technically possible and are being used presently with great success. This paper will concern itself with the general aspects of large screen design, by using modern technology and the latest findings with regards to fatigue strengths relative to the laws of vibration. It also will investigate the technical and economical limits of such designs.

Jan 1, 1983

By John K. (Original by) Berry

The handling and disposal of mine water is a much larger problem than is apparent at first glance. Many more tons of water are removed from underground coal mines in the United States each year than tons of coal. In the old anthracite region of Pennsylvania the average was around 32.7 t (36 st) of water for each ton of coal produced, while bituminous mines average about 4.5 or 5.4 t (5 or 6 st). Water encountered in the mines may come from several different sources. In mines with light cover and without a firm solid roof, rain may seep directly into the workings. This is also true of deeper mines where pillar falls have broken the roof to the surface. The top under creek beds is generally faulty and broken and water comes through the roof at this point. Deeper mines are frequently overlain by water-bearing strata and pillar breaks and faulty top can admit water, while places running to the dip often accumulate water which comes up through the bottom. In all cases, except where passing under a year-round stream, the amount of water made is usually pretty closely connected with the weather-more water during the rainy season, less in the dry, although the deeper a mine is, the longer it is before changes in rainfall are felt. Another source of water, not connected with seasonal changes, is old water, accumulated over a period of time in abandoned workings of the mine, or from flooded adjacent mines. Here the water filters through the coal, the parting, or comes up through cracks in the bottom. Similarly, core holes, drilled to prospect the property, can be a source of unexpected water and modern safety requirements for dust-allaying water at the working faces can turn a pleasant working area into a soggy mess over the weekend if the system is not properly maintained and operated. Why water must be disposed of is obvious. If allowed to accumulate, sooner or later the mine will fill up, or at least it will become "roofed" in low places, blocking ventilation and traffic. It must be controlled long before it reaches this stage. Water standing in the working faces is unpleasant for the men who have to work there and also cuts down on the amount of work they can do, as they must watch where they step all the time. It is especially unpleasant in low coal.

Jan 1, 1981

By Henry N. McCarl

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Jan 1, 1966

By Eugene M. Trisko

Presentation Overview State-Of-The-Art Scrub/Switch Analyses > Allegheny Power System > PSI Energy UMWA Phase I Coal Interests > 16 Phase I Scrub Plant Coal Profiles > Coal Price/Emission Allowance Interaction Southern Company Case Study > 2+ Million Ton Phase II Allowance Purchases > 10+ Million Ton Phase I Coal Switch > Georgia PSC Proposed Fuel Price Cap > Shift/Avoid Georgia Scub Costs Through System Allowance Purchases

Jan 1, 1993

By M. W. Brandt

In the November 1957 issue of "Chemical Process Engineering," a British publications, there appeared an article entitled "Correct Selection of Drying Equipment." The author wrote as follows "Whether batch drying or continuous drying' methods are applied, the basis of efficient drying is heat distribution, control of rate of heat input, and heat transference from heating medium to the particles of the material to be dried." The author continues: "Because the efficiency of direct dryers, such as hot air or hot gas dryers, increases with rising inlet temperature of the drying air or gas when exhaust temperature remains fixed, the highest practical drying temperature should be used. Exhaust air should leave the dryer at the lowest possible temperature, but as fully saturated with moisture as possible." It is certainly conceivable that the author of this article by outlining the basic requirements for efficient drying methods has unwittingly given the reasons why fluidized drying is rapidly being adopted for so many industrail applications, including the dryingof fine coal. An examination in greater detail of the individual basic requirements for efficient drying as outlined by the author is perhaps the most logical starting point.

Jan 1, 1958