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By George Owusu, Ernest Peters, A. J. Monhemius, G. W. Warren, David B. Dreisinger, E. Peters

Lignin sulphonic acid (or its salt) is commercially used as a surfactant in the Zinc Pressure Leach process. The surfactant prevents liquid sulphur from coating unreacted zinc minerals thus allowing the leaching reaction to proceed. Infrared studies have been performed using the Attenuated Total Reflection-Fourier trans- form infrared technique (ATR-FTIR); the application of this technique permitted the "in-situ" study of the adsorption of the surfactant by sphalerite. The spectral records obtained from study indicate that the lignin sulphonate ions are both physically and chemically adsorbed by the sphalerite.

Jan 1, 1993

By D. C. Panigrahi

The paper presents the development of a thermodynamic based network analysis model. It uses transient heat flow algorithm for computing the heat flow from strata and predicts the environmental condition in different branches of the network. Along with the environmental condition, the mass flow distribution in network is computed by using nodal pressure method based on linear theory approach. The algorithm has been coded using object oriented programming approach and it has been validated in actual field condition. The correlation is satisfactory.

Jan 1, 1997

By Peter H. Grimley

It is important to realize that lending institutions have a very different risk-profile from that of an equity investor. For bank financing, a feasibility study must address the concerns of the lender and these can be summarized under the four 'PI Is: Project, Performance, Product and People. Generally, feasibility studies focus on the measurable project risks associated with a new venture, but frequently insufficient emphasis is placed on key risk areas such as ore grade and metallurgical recovery. Before accepting full or even partial non-recourse risk, financial institutions will demand evidence that the project was constructed according to specifications and within budget and that its Performance within agreed limits has been demonstrated. Product risk should be discussed in detail in any feasibility study. For industrial minerals, penetration of the market can be critical to success and for commodities with volatile prices, the sensitivity of the cash flow to a range of prices should be carried out. Methods of reducing price risk such as long term contracts or, in the case of gold, forward selling should be carefully evaluated. The People risk is rarely discussed in feasibility studies, but can be a key element. Few projects turn out to be faithful copies of the study and the ability of the operator to identify

Jan 1, 1988

By Bernard Amadei, Michael J. Robison

The purpose of this paper is to present the results of 102 mu1tiaxial tests conducted on cubical specimens of Indiana limestone using the mu1tiaxial apparatus available at the University of Colorado at Boulder. These tests include (1) uni-axia1 compression and tension, (2) bi-axial and tri-axial compression, (3) biaxial compression- tension and (4) tri-axial compression-compression- tension. The applicabi1ity of existing failure criteria to predict the strength of the tested materia1 is discussed.

Jan 1, 1986

By Mehmet Maral

Various types of Tertiary (Miocene) lignite occurrences had been formed and alternated with volcano-sedimentary Bigadiç Formation in the field of study, which resides in the middle and eastern parts of Biga Peninsula. The focus of the study is to identify the geochemical and petrologic properties of coal occurrences and the formation mechanism of the deposits. A comparative study of the deposits will also be studied. Biga Peninsula is a very rich zone in terms of both metallic ores and industrial minerals. Most of the metallic deposits and industrial occurrences in the region have been known and mined throughout the history. This richness of the region is related to the volcanic and tectonic activities that have developed during different geological periods. These activities are the main reasons of weathering and alteration phenomenon.

Jan 1, 2005

By Joe M. Bryan, George E. Rodger

The development of small precious metal mines in the western states has been directed at heap leach operations. Crushing plants are an essential adjunct to heap leach operations. They must meet environmental air quality regulations which generally follow a similar pattern from state to state. Prior to mine construction a permit must be obtained and an operating permit granted during or shortly after the start-up period. The typical construction permit application consists primarily of drawings, specifications and an explanation sufficient to indicate that the mass of particulate matter entering the atmosphere is below minimum standards. The operating permit may be granted following demonstrations that air emission control equipment or methods comply with information submitted in the construction permit application.

Jan 1, 1987

By R. Y. Wan, Corby G. Anderson, L. Ernest Krys, M. C. Fuerstenau

Since 1942, refractory precious metal concentrates at the Sunshine mine have been processed for antimony metal recovery using a novel leach-electrowin method. This is counter to most antimony production facilities where pyrometallurgical techniques are usually relied upon. The key step for removal of the antimony has been an ambient pressure alkaline sulfide leach. In 1990, a comprehensive laboratory study was undertaken to better understand this process. Factors studied included temperature, agitation, concentrate regrind, alkaline species concentrations, sulfur species concentrations and solids concentration. Details of these studies, as well as a brief description of Sunshine metallurgical processes, will be presented.

Jan 1, 1993

By W. M. Ma, Daniel W. H. Su, K. Centofanti, Yi Luo, W. L. Zhong, Syd S. Peng

3.1 INTRODUCTION The final subsidence basin discussed so far is that developed long after mining has stopped. In a supercritical final subsidence basin, the central portion subsides uniformly. Thus any structures located there are not subjected to any final permanent surface deformation. But this statement is only true for the final subsidence basin. When the face is moving, the structures are subjected to dynamic deformations associated with the dynamic subsidence basin. For instance the house in front of a moving face (location 1 in Fig. 3.1) is subjected to the maximum tensile strain and the maximum positive curvahue. When it falls behind the face in location 2, it is subjected to the maximum compressive strain and the maximum negative curvature. When the house is far behind the face in location 3, it returns to its original condition with only uniform subsidence. However, the magnitude of the dynamic deformations may be sufficiently large to damage a structure in locations 1 and 2 before it reaches location 3. Therefore it is very important to study the characteristics of the dynamic subsidence basin. Under normal conditions, when the face has advanced for a distance approximately one-sixth to one-third of the seam depth from the setup entry, depending on the seam depth and the physical properties of the overburden strata, the movement of the over- burden strata reaches the surface, whereupon the surface also be- gins to deform. Thereafter, the surface point where the movement initiates is always located at a fixed distance ahead of the face. The angle between the vertical line at the faceline and the line connecting the movement initiation point on the surface and the face- line is the angle of advance influence, w. The angle of advance influence can be used to determine the distance, [ 1], which is the influence zone ahead of the face. w is approximately 20O to 35 O for the northern Appalachian coalfield (Peng and Geng, 1984). The movement of each surface point is a relatively complicated process both in time and in space, because the relative position between the faceline and each surface point varies continuously, so that the direction and rate of movement for each surface point differ. In the following sections, the movements of each surface point on the major cross section are illustrated. 3.2 DYNAMIC SURFACE MOVEMENTS Dynamic surface movements include dynamic subsidence and displacement. The movement of each point on the subsidence basin is different as the face advances from 1 to 6 (Fig. 3.2). Surface points A and B, being far in front of the moving face, subside and displace toward the face (i.e., from A to A' and from B to B'). Point C, which is quite near but in front of the moving face, subsides continuously but displaces initially toward the face and then turns to pure subsidence ending up at C'. Point D, which is behind the face above the gob, subsides continuously, but displaces initially toward the face when it is in front of the face and reverses to follow the moving face when it is behind the face, with the amount of displacement toward the face being larger than that following the face. As a result the net displacement is toward the center of the gob (i.e., from point D to D'). The same statement is true for point E. For point F, the net displacement is zero, i.e it appears to have dropped down vertically to F'. For points G to I, the net displacements are in the direction of face advance except the magnitudes are increasing in sequential order. Point 1, has reached the final dynamic position of 1'. In other words, the face has passed sufficiently away such that it does not affect the movement at point I. All other points (A to H) are still within the face influenced area. 3.3 DEVELOPMENT OF DYNAMIC SUBSIDENCE PROFILES When the face has moved for a distance of h/6-h/3 from the setup entry, surface subsidence reaches the surface. At this time the surface subsidence basin is very mild (S, in Fig. 3.3), and it is symmetrical about the center. As the face continues to advance, the maximum subsidence continues to increase, and its location moves with, but falls farther behind the face. When the face has advanced a sufficient distance, e.g., (0.9-2.2)h, away from the setup entry, the maximum subsidence reaches the maximum possible value (curve S,). At this time, the dynamic subsidence profile is fully developed. Thereafter both sides of the dynamic subsidence profile become stabilized. The subsidence profile on the face side moves with the advancing face in an orderly manner (curves S, and S,). When the face stops, the face side of the profile continues to subside and becomes stabilized (curves;) sometime after. Curve S; is the final subsidence profile (see Fig. 2.22). 3.4 DEVELOPMENT OF DYNAMIC DISPLACEMENT AND SLOPE PROFILES The dynamic displacement profile moves with the advancing face (Fig. 3.4), but changes according to some specific rules. When the face has advanced to A, the surface begins to move and its dynamic displacement profile has two maximum values (curve Ua): one positive near the setup entry moving toward the face advancing direction and the other negative on the face side also moving toward the face advancing direction. As the face continues to advance, the positive maximum displacement on the setup entry side increases and moves toward the face continuously. The same statement is true for the negative maximum displacement on the face side. When the opening increases to the critical size, both the maximum positive and negative displacements reach the peak values and remain constant thereafter. Notice that when the opening becomes critical in size, the point of zero displacement no longer moves with the advancing face. Rather it spreads into an area of zero displacement (curve Ue) and expands as the face advances. When the face stops, the displacement on the face side continues until it becomes stabilized (curve Úe). Curve Úe is the final displacement profile. The ratio of maximum dynamic to final displacement ranges from 60 to 75%. The dynamic slope profile follows the same patterns of change. The ratio of maximum dynamic to maximum final slope ranges from 50 to 80%. The maximum slope decreases with in- creasing rate of face advance (Peng and Geng, 1984). It must be pointed out that except for those near both sides of the profiles, each point on the displacement and slope profiles is subjected to a cycle of positive and negative displacements and slopes depending on its relative position with respect to the face.

Jan 1, 1992

By P. J. Bethell

This paper reviews current fine coal cleaning circuitry, including water washing cyclones, tabling and froth flotation. It goes on to examine possible future beneficiation based on emerging technologies. Circuits considered include those incorporating spirals, fine heavy medium cycloning, hydrosizers and column flotation.

Jan 1, 1988

By R. W. Smith, M. C. Fuerstenau, G. X. Xang

Nonliving dried water hyacinth (Eichhornia crassipes (Mart.) Solms) roots were investigated for the biosorption of cadmium, lead and other heavy metal ions from aqueous solutions. Dried water hyacinth roots, when suspended in solution, strongly and rapidly sorb several different metal ions. Factorssuch as reaction time, pH, the initial concentration of metal ions, the presence of other metal ions and biomass concentration were investigated. The adsorption was shown to follow the generalized Langmuir adsorption equation. The relative affinity of the roots for lead is greater than that for cadmium. The batch sorption kinetics of the uptake of cadmium and lead can be described by an apparent first-order reversible reaction model. The roots could be regenerated after the metal ions were stripped. Successful desorption of Cd and Pb from the biomass by acidic CaCl2 solutions revealed that the metal uptake phenomenon is reversible, implying physical sorption of Cd and Pb.

Jan 1, 2000

By Terry Owen

Business development process. Throughout Cyprus Amax's early months in Russia, the company stayed focused on what was needed from a deposit for economic success. Cyprus Amax's reason for success in Russia is that all involved - its Russian partners, the workforce and expatriates - provided a focused effort that served the project as it worked through the tender process and the Russian regulations. The company developed an understanding of the regulatory process by working with solid, ethical partners. Infused into the Kubaka management structure were Russians with the knowledge to facilitate the process and a professional group of expatriates. Developing credibility and a solid rapport with the Russian mining authority was critical to the success of this venture. Identifying and gaining the trust of key Russian individuals was also critical during the early stages. Gaining their trust and building credibility was part of the process. These key Russians were brought to the United States to visit existing Cyprus Amax mines. These efforts proved valuable in building an understanding with the Russians about the kind of company Cyprus Amax is and the kind of efficient operations that it can run. This was a learning process for all parties. Fortunately, the company was dealing with intelligent and educated people.

Jan 1, 1997

By Samuel M. Cassidy

The exact date of man's first use of coal is lost in antiquity. The discovery that certain black rock would burn was undoubtedly accidental and probably occurred independently and many times in the world over thousands of years. It is quite likely that these independent discoveries were made when primitive man chanced to build camp fires on exposed ledges of a black rock, then was amazed when it caught fire. The Chinese recorded the use of coal 1100 years before the Christian Era and from the Bible we learn that King Solomon was familiar with coal in what is now Syria. In Wales, there .is evidence that the Bronze Age people used coal for funeral pyres, and it is known that the Romans used this fuel. There are other ancient references. So the knowledge that coal would burn, and even some uses of that knowledge, go back thousands of years. However, practical and consistent use of coal seems to date to England in the Middle Ages.

Jan 1, 1981

By Robert A. Haney, Richard T. Stoltz

In July, 1988, the Mine Safety and Health Administration (MSHA) Advisory Committee on Standards and Regulations for Diesel-Powered Equipment in Underground Coal Mines recommended that the Secretary of Labor set in motion a mechanism whereby a diesel particulate standard can be set. Prerequisite to establishing a standard would be the development and evaluation of instrumentation to measure diesel particulate. In response, the Mine Safety and Health Administration, Dust Division, has been evaluating instrumentation that can be used to determine diesel particulate levels in underground mines. This instrumentation employs the principle of impaction to separate particles by size, thereby, separating the diesel and nondiesel particulate. Separation of the particulate by size was chosen because diesel particulate is generally less than 1.0 micrometer in size. No other methods have been developed to successfully distinguish between the coal and diesel particulate. MSHA developed an impactor that is inexpensive and compatible with existing pumps and filter holders. The instrumentation evaluation has primarily focused on the repeatability and performance of several personal dust samplers. The samplers tested include the Sierra-Andersen Model 298 personal impactor and MSHA developed personal impactor. The MSHA impactor is inexpensive and compatible with the existing pumps and filter holders. In addition to evaluating the precision and performance of these instruments, tests have been conducted to determine background levels of submicron particulate in nondieselized coal mines and to measure the submicron particulate content in dieselized coal mines. Tests were conducted in coal mines where diesel equipment was used only in outby areas and also in coal mines where diesel equipment was used for face haulage. This paper describes the results of the tests and provides a description of the instrument at ion used to conduct the tests.

Jan 1, 1989

By A. Maréchal

It has been shown since a few years that the problem of estimating recoverable reserves should be solved by using specialized statistical techniques : whenever the selected blocks are chosen without any other constraint than a cut-off grade criterion, the problem of estimating the corresponding tonnage-grade curve is resolved by estimating the local histogram of block grades. Two major statistical techniques are currently used by geostatisticians to estimate local histograms : the "average conditional distribution" technique (Parker, Journel, Dixon 1979) and the disjunctive kriging technique. (Matheron, 1976, Jackson, Maréchal, 1979). Both have proved to be applicable in practice, with their pros and conconcerning their practibility and versatility.

Jan 1, 1982

By Byron N. Cooper

The Revenue Act of 1926 provided for five simple categories of natural resources to have the benefit of depletion allowances. In the 1947 Revenue Act, the number was increased to twenty-five, and in the 1951 Revenue Act to fifty-four. Of this number, fourteen were allowed 5 per cent; nine, 10 per cent; twenty-nine, 15 per cent; one, 23 per cent; and one (oil and gas), 27.5 per cent. The 1951 Revenue Act created a host of difficulties, including application of the "end- use criterion" and determination of the commonly accepted meaning of such terms as limestone, dolomite, chemical- and metallurgical-grade limestone, marble, calcium carbonates, and magnesium carbonates. Dolomite, for example, was listed at 10 per cent depletion allowance, but without definition. In the great amount of litigation growing out of the 1951 Revenue Act and its administration, it became essential to understand the derivation and subsequent usage of these common geologic terms. One thing that became clear was that our definitions changed significantly between the time that the 1951 Revenue Act became law and the time that later cases were tried. Some geologists neglected to learn about first usages of such terms as metallurgical limestone, and about meanings that were applicable when the 1951 Revenue Act was written and passed. Legal meanings in this paper are discussed in the light of certain famous cases that have been tried and settled.

Jan 1, 1966

By R. Bruce Tippin

The silicates represent the largest and most common group of minerals on earth. Yet in spite of the chemical similarities, numerous mineral processing plants worldwide are operating successfully to yield varied commercial products for numerous uses. The silicates that are commercially produced in the United States by flotation include quartz, feldspar, mica, spodumene, talc, kaolin, and wollastonite. The operation of several plants and the conditions affecting mineral separation by flotation are described. Because the process is usually dictated by the desired market, specifications for the most common products are provided. Potash is a basic fertilizer component, along with phosphate and nitrogen. Potash is typically produced from underground evaporite beds or recovered from natural brine solutions. Flotation of potash is unique in that it is processed in a saturated salt solution. The potash flotation process is outlined and several commercial operations are described.

Jan 1, 1999

Since first introduced, the coal mine roof rating (CMRR) has been widely accepted as a tool for geologic characterization and mine planning. This paper discusses the application of the CMRR to another practical ground-control problem: extended cuts. Extended cuts, i.e., cuts greater than 6 m (20 ft) in length, are commonly used with remote-control continuous miners. Extended cuts can greatly increase productivity, but they have been associated with a number of fatal roof-falls. When extended cuts are attempted in weak roof material, the roof may collapse before it can be bolted Until now, it has not been possible to predict where conditions may not be suitable for extended cuts. In this study, data on the CMRR and extended-cut experience were collected at 36 mines in seven of the United States. It was found that, when the CMRR was greater than 56, deep cuts were routine in nearly every case. When the CMRR was less than 37, extended cuts were almost never taken, and, when the CMRR was between 38 and 56, extended cuts were sometimes, but not always, feasible. The data also show that extended cuts are less likely to be stable if either the entry span or the depth of cover increases.

Jan 1, 2000

By S. Dempsey

Since its passage in 1872, the Mining Law has been modified on several occasions to meet the changing needs of America's society and economy. Despite its evolution, the Mining Law continues to be criticized as outdated. This paper briefly traces the major points in the history and evolution of western mining laws, and reflects on the current status of ongoing discussion to reform the 1872 Mining Law.

Jan 1, 1997

By J. D. Forrester

I have availed myself of the opportunity to prepare, and to give this talk because, as incumbent Chairman, I am directed by the Bylaws of the Council of Education to make an Annual Report of the Council activities which have transpired during the past year. In addition, and inasmuch as I have this captive audience, I am taking the liberty to express also some beliefs I hold about various other elements of Mineral Industry education. First, my report is that constructive progress has been achieved in the Council of Education during 1960-61. These advancements have been particularly notable through projects carried on by the Committee on Meetings and Programs, by the Student Chapters Committee, by the Accrediting Affairs Committee and by the Committee for Securing Better Representation of Mineral Industry Colleges. I believe each of these groups will report concerning details of their respective programs at the Business Meeting of the Council. On the other hand, not as much has been done in some areas of work as I had hoped would be the case when I took office as Chairman last February. Let me make clear that these delinquencies, for the most part, have resulted through my ineptness in handling of affairs; they are not caused by the failure to perform various assignments which I have given to council members.

Jan 1, 1961

By R. Tanaskovic

The objective of study of climatic conditions in underground mines is to create a working environment suitable for normal development of operations. Disregarding the fact that the development of equipment and technology, especially during the past decade, made the work in underground mines much easier, it is observed, according to the number of professional publications, that increasing attention is devoted to the study of climatic operating conditions in mines of many countries. This indicates that the climatic operating conditions are closely connected with productivity, and in turn with mine production profitability, in addition to the protection of manpower health and working capabilities. Usually, the concept of unfavourable climatic conditions of operation implies increased mine air temperature and humidity and low air flow rate, resulting in impeded heat exhange between human organism and working environment. As known, above phenomena are present in deep underground mines where the heat problem exceeds the-problems related to other features of natural conditions of mining. On the contrary, unsuitability of climatic operating conditions in mines with shallower mining depths is manifested by inadequate heat, particularly during the cold winter period. The two stated aspects of unsuitable climatic operating conditions are not solvable only by mine ventilation, so the former case requires cooling and the later one heating of the air used to ventilate the pit, or part there of where the phenomena are manifested. Study of climatic operating conditions in mines is, due to the number of factors involved, a complex and time consuming task, and this was, among others, one of the reasons for inadequate study of these problems in many mines. However, it is evident that further development of mine production imposes the need to make the climatic operating conditions in mines similar to those existing in other activities, where increasing attention is being devoted to the improvement of these conditions. Development of mining industry in Yugoslavia, particularly over the past decades, caused several of our mines to approach mining depths where the heat regime has a major influence on climatic operating conditions. This imposed the need to determine and investigate heat regime parameters, especially those that cause unsuitable operating conditions. The results of such investigations in the case of the deep part of Lead and Zinc Mine "Trepca" - Stari Trg are briefly reported in this paper.

Jan 1, 1980