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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 Jim V. Rouse

The mining, beneficiation, and processing of phosphate rock in the Florida phosphate district constitutes a large portion of the southeastern mining industry. For example, 1973 production is reported to have been approximately 35 million tons of phosphate rock (Guimond and Windham, August 1975) and production has increased to over 45 million tons in recent years. The 1973 activity involved the movement of approximately 127 mil lion tons of material. From the hydrologic standpoint, this mining and beneficiation requires the dewatering of ore horizons, pumpage of large quanitites of water for mining and processing operations, and the entrainment of immense quantities of water in waste slurries. Also of significance is the fact that the cited 1973 production involved the disruption of approximately 3200 curies of radium and over 6000 curies of uranium. Much of this material reported with waste products, with the potential for contamination of area ground waters. However, natural removal mechanisms active within the area have generally been effective in preventing significant contamination of the ground-water resource.

Jan 1, 1983

By F. J. Chernosky

In the past, a number of papers have been written on the use of various reagents as coal flotation frothers. For the most part, these papers have attempted to correlate the intrinsic chemical and physical properties of the reagents or reagent groups to the floatability of various fine coals. Because of the type or nature of evaluations made, chemically pure reagents were normally used. Generally, these reagents are unavailable in commercial quantities. Therefore, the results obtained with these reagents were usually limited in usefulness to the plant operator or metallurgist. This paper presents the results of a study in which commercially available forms of various reagents were used as flotation frothers. Flotation procedures which would conform in general to those employed in a large number of commercial coal flotation plants were utilized. The objective of the test was to compare these reagents on yield-selectivity-cost basis, that is, (1) the yields obtained, (2) the ash levels obtained, and (3) the reagent cost relating to these results.

Jan 1, 1962

By E. G. Loesche

Grinding mills in which the comminution takes place between rollers and the surface of a disc, table or ring are generally known as roller type mills. The Loesche Mill, also known as the Disc Roll Mill, is a special type of roller mill in which the grinding surfaces consist of two rollers assembled over a horizontal disc or table which rotates at a relatively low speed. This design is particularly applicable to industry's present day demand for large capacity grinding mills.

Jan 1, 1964

By Donald C. Moore

Asamera Minerals Cannan Mine has been producing a 170 g gold/tonne (5 oz gold/ton) siliciaus flotation concentrate since July 1985. Flotation concentrate is shipped to a smelter for gold recovery. Numerous processes have been investigated to economically produce bullion on site. This paper describes the laboratory and pilot plant test results of a bacterial assisted oxidation of the refractory minerals. Economic comparisons with autoclaving and roasting processes are included.

Jan 1, 1989

By R. S. Shepard

A quick glance at a-portion of the title of this discussion -'Rolling With The Punch" may immediately lead you to assume that I am about to expound on the so-called manly art of self-defense. So that you will not have been misled entirely we will devote our considerations to a far more important art and if I may, I should like to begin by quoting Vincent Van Gogh. According to a literal translation the artist in describing one of his famous paintings said "these peasants are eating their potatoes with those very hands that dug them from the earth' and put them in the dish". Vincent Van Gogh may not have realized at that time, that he could likewise have been describing what is probably one of the oldest of all arts - the art of Material Handling - an art that man with the aid of science has tried to improve since the beginning of time.

Jan 1, 1963

By Todd S. Harris

Industrial minerals or non-metallic minerals are loosely used terms applied to a diverse assortment of materials which, in many cases, have nothing more in common other than the fact that they are neither metals nor fuel minerals. To help bring order to this otherwise random assortment of minerals, we have grouped these materials into two main categories; chemical and physical minerals, and nine sub-categories based on end-use applications as shown in Table 1. Chemical minerals are products which are principally used for the specific chemical elements they contain, whereas physical minerals are products which are used to meet specific performance specifications. The latter part of the 1970?s, in particular 1978, were considered peak years in terms of production and sales for many industries, By using 1978 as a base year, we can evaluate wherethese markets stand today after the recession of the early 1980's and the recovery which began several years ago. From this historical overview and appraisal of the current situation, various assumptions can be drawn as to which markets are expected to perform well into the 1990's.

Jan 1, 1987

By R. J. Clements

The waterway transportation system in the united states consists primarily of the Mississippi river system. With its navigable tributaries, it is 12,500 miles long. This system naturally accesses about 40 percent of the nation. With its connecting railroads and highways, the river system accesses the united states from the Appalachian mountains in the east to the rocky mountains in the west. Within this area is the vast majority of our agricultural, industrial and material resources.

Jan 1, 1984

By Henri Letient, Tom Aley, David Evans

Antamina is a large open-pit copper and zinc mine located within the Central Andes of Northern Peru at an altitude of 4300 masl. The facilities are situated within the headwaters of several watersheds, within the Amazon basin. Nearby villages rely heavily on springs and streams for drinking and irrigation water. The principle source of baseflow during the dry season is from Cretaceous karstic limestone aquifers. Antamina will produce nearly 1.4 billion tonnes of waste rock over its mine life. Finding suitable sites for storing large volumes of waste rock is often a challenging task – especially in karstic, alpine terrain. Detailed hydrogeological investigations are essential for delineating the karstic hydrogeologic watersheds associated with the proposed waste facilities, which are often very different than topographic (hydrologic) watersheds. Contamination vulnerability mapping at Antamina consisted of geological and karst mapping, geophysical surveys, geochemical testing, dye-tracer studies, drilling and aquifer testing. Detailed mapping followed by dye-tracer studies proved to be the most cost-effective methods for characterizing the karst aquifer systems. The results were used to optimize waste rock management at the site to minimize potential impacts on groundwater resources.

Jan 1, 2005

By W. Dan Hausel

Archean supracrustal rocks of the South Pass greenstone belt of western Wyoming have been an important source of gold and iron ore. Actual gold production statistics are incom- plete although gold production estimates for the South Pass- Atlantic City district range from a low of 2.0 Mg (70,000 oz) (Koschmann and Bergendal, 1968) to a high of 9.8 Mg (327,000 oz) (Hausel, 1980). From 1962 to 1983 iron ore was also mined from the greenstone belt and production totaled more than 91 Mt (90 million It). The supracrustal rocks of the South Pass greenstone belt occur in a tightly folded synform bounded by Late Archean granite and granodiorite. The youngest of the Archean successions has a reported Rb-Sr isochron age of 2.8 b.y. (Stuckess, et al., 1985). Metamorphism of the supracrustals increases towards the flanks of the belt and is amphibolite-grade enclosing a small island of greenschist facies rocks. The supracrustal sequence consists of metasedimentary and metaigneous rocks that are divisible into four mappable units. The metasediments include metagraywacke, quartzite, pelitic schist, banded iron formation, metaconglomerate, and graphitic schist. Metavolcanics include metabasalt, meta-andesite, and ultramafic schist. These supracrustals have been intruded by mafic sills and dikes and tonalitic stocks and dikes. Two granite plutons and associated pegmatites intrude the supracrustals in the western portion of the belt, and the supracrustals exhibit both fault and intrusive contacts with granitic batholiths along the western and eastern margins. The northeastern flank of the Archean belt is unconformably over- lain by Paleozoic sediments, and the southern portion of the belt is onlaped by Tertiary sediments.

Jan 1, 1990

By Adrian Brown

The primary method of slope stabilization is ground water-control. Recent research has established the properties which slope materials must exhibit in order for stabilization measures to be feasible, but there is little guidance in the literature about suitable field tests to develop the parameters needed for this evaluation. This paper presents a proven method for large scale testing which allows an evaluation of the feasibility of ground water pressure control in a reasonable cost and time frame. Methods of performance and analysis of the test are presented, and the method is illustrated by reference to case examples.

Jan 1, 1984

By S. L. Bessinger

In the design and specification of a ventilation system for an underground mine, it is necessary to make reasonably accurate estimates of the pressure losses in the various airways of the mine. These estimates can be made with little difficulty for open airways with simple geometric cross-sections, such as those cut by continuous miners or tunnel-boring machines. The situation is much different on a longwall face, where the airway's complex geometric cross-section and the presence in the airway of obstructing equipment having a variety of shapes make it difficult, if not impossible, to estimate pressure loss using traditional methods of calculation. Headlosses in mine entries are calculated using Atkinson's Equation (1). [H = (English) H = (SI) (1)] where H = pressure ,loss, in. of H20 (Pa) K = friction factor, lbf min2/ft"4(Kg/m3) P = perimeter, ft. (m) L = airway length, ft (m) Q = airflow quantity, ft3/min (m3/sec) A = flow cross sectional area, ft2 (m2)

Jan 1, 1987

By James E. Breland

Society's growing concern over the number of deaths and serious injuries occurring in coal mines, coupled with a growing sentiment to develop and promulgate improved mandatory health or safety standards, was no doubt the basis for passage by Congress of the Federal Coal Mine Health and Safety Act of 1969, being Public Law 91-173 approved December 30, 1969. Even prior to passage of the Act, strong reaction was quick to arise concerning the effect of such legislation upon the coal mining industry. Initial response varied from mild forms of criticism to' the expressed fear of complete suspension of operations and mine closings. Primarily responsible for these early forms of skepticism were speculative or fanciful cost estimates which led operators to contemplate a less than prosperous existence. However, in spite of this unfavorable outlook, the majority of the operators have faced up to the situation and have been striving to comply with the Act and the regulations issued thereunder. While encouraging strides have been made toward implementation of the Act, it must be recognized that noticeable results have been attained only through many months of determined effort and, as anticipated, at quite heavy expense to the operator.

Jan 1, 1973

By J. Engesser

This paper discusses the effect that water chemistry, and water treatment have on pre-fired pellet quality and bentonite-binding effectiveness. A discussion concerning the effect that water temperature, water chemistry, water treatment, and surface area have on disc filter productivity and filter cake moisture is also included. This report is a summary of the data that were presented in five previous research reports, which are listed as references in this paper.

Jan 1, 2003

By C. L. Sarff

[Automation has become a word that means many things. To management it is the end of the rainbow; you push a button and all your problems are solved. To the working man it is a horrible monster that is taking his livelihood away. To the maintenance man it is a complex that overwhelms him when he thinks of trying to find the trouble when the machine is not operating, properly. Automation has been with us in the coal nines for many years. Long before my time you were using float switches on mine sumps to control the level of the water. That?s automation in the truest sense of the word, but we call it automatic and think nothing of it. If we use the word automatic instead of automation your mine electrician and mechanic will take hold of the problems in stride.]

Jan 1, 1962

By David H. Carrillo

HYL has developed a sticking tendency test which accurately predicts behavior of iron oxide feedstocks in the HYL III process. Test results together with pilot plant experimentation and commercial scale demonstrations permit the conclusion that lump ores will not agglomerate at 960°C (1233 K) in an HYL III Plant. Pellets may also be processed without agglomeration at 960°C (1233K) with the addition of no more than 5 percent lump ore. Using the HYL III process, the ironmaker can exploit feedstock market conditions without sacrificing plant productivity or energy efficiency.

Jan 1, 1981

By Dale R. Ralston, Roy E. Williams, Gerry V. Winter, George L. Bloomsburg

GENERAL STATEMENT Data frequently can be collected by several dif¬ferent methods. The method required for the nec¬essary precision for inflow prediction to mines should be selected and other methods avoided. Pre¬cision monitoring or measuring techniques fre¬quently require more time, expertise, and expense in their implementation that may not be justifiable. The temporal distribution of the data needs also may dictate the method used for data collection. Continuous recording devices may be required for time sensitive data whereas point measurements of other parameters may be adequate. Data needs will vary as the hydrologic investigation proceeds. In¬itial data needs may require only a qualitative col¬lection of data such as the areal distribution of precipitation. Subsequent data needs may require the measurement of ground water levels to the near¬est hundredth of a foot. Data requirements can be difficult to fulfill for ground water systems. This is particularly true for anisotropic, heterogeneous hydrostratigraphic units since the hydrogeologic parameters vary both ver¬tically and areally. Techniques exist for determining the storage characteristics of both unconfined and confined hydrostratigraphic units but these pro¬cedures require the installation of multiple wells in the same unit which may be impractical. Specific tests are discussed subsequently that permit the determination of vertical hydraulic conductivity. Data collected from field procedures or tests are generally preferred to laboratory derived data. This is especially true for hydrogeologic parameters such as hydraulic conductivity. SURFACE WATER SYSTEMS Precipitation Precipitation data can be collected from sources that maintain a historical record. The US Depart¬ment of Commerce, National Oceanic and Atmos¬pheric Administration (NOAA), maintains weather observation stations across the country. Such a sta¬tion frequently can be found near a proposed mine site but the type of weather data collected varies from station to station. Fortunately, precipitation data are collected ubiquitously. The data collected by NOAA can be purchased for the area of interest in the form of monthly and annual tabulations. Private weather stations constitute a second source of precipitation data. Existing data usually are analyzed by one of three methods. The station average method merely sums the depth of precipitation at each station and divides the sum by the number of stations as fol¬lows: [ ] where Pavg is the average precipitation (L), P, is the depth of precipitation at station i (L), and N is the total number of stations. This method is applicable where there are a relatively large number of stations uniformly distributed across the area (Hjelnfelt and Cassidy, 1975, pp. 71-72). The second method, called the Thiessen poly¬gon method, weights the precipitation at each sta¬tion in direct proportion to the area it represents without consideration of topography. The stations are plotted on a map and perpendicular bisectors are drawn on the lines connecting the stations. The polygons formed by these bisectors constitute the area that the precipitation for that station repre¬sents. The overall precipitation can be calculated with the following equation:

Jan 1, 1986

By Z. Hladysz

It is common to nine a coal seam affected by previous extraction of a coal seam below. As a result of that severe problems may occur during the extraction process. This paper presents the analysis of undermining effects based on field observations. A simplified method for the evaluation of risk in undermining operations is presented and predictions of the degree of possible damages to the undermined coal seam is given.

Jan 1, 1985

By John D. Kalasky

Ventilation is necessary in coal mines to supply fresh air to the working faces for the health, safety, and comfort of the miners, and for the circulation of air to the extent that it will dilute, carry off, and render harmless the noxious or dangerous gases generated. Adequate ventilation depends upon good face control, as well as upon a well designed and properly controlled overall ventilation system. Generally, this includes fans, airways, overcasts, air locks, regulators, checks, and canvas or plastic stoppings near the working places to prevent short circuiting of air, and effective bleeders to maintain a continuous flow away from the working places along the pillar lines at all times and to prevent diffusion of methane back to the pillar line in case of temporary interruptions in ventilation. In the development of a new mine, or the virgin area of an old mine, the main headings should properly be considered a construction project, designed with, only the number of permanently supported (roof) headings required to conduct the necessary air volume to and from the major panels in which mining is conducted by room and pillar or longwall methods. Although subject to hazards from methane quite frequently and requiring constant and careful attention at all times, development of headings has some built in safeguards which make it a less difficult problem in control of methane than exists in pillaring.

Jan 1, 1973

By R. M. Clowes

Lithoprobe is a collaborative, multidisciplinary research project which is providing new insights into the tectonic evolution of the North American continent through its work within ten study areas across Canada. For the mining industry, such results provide a well-constrained regional framework and better understanding of tectonic processes which lead to the development of ore deposits. In mining camps, seismic reflection methods have proven effective in imaging shallow to moderately dipping litho logic contacts as well as structural features, and in some cases have been used for the direct detection of ore bodies. Here, short case histories are provided for the Abitibi greenstone belt (VMS deposits) in Quebec and the Thompson nickel belt in Manitoba.

Jan 1, 1999