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By Thomas E. Ban

The continuous sintering process was invented more than 60 years ago by two metallurgists, Arthur S. Dwight and Richard L. Lloyd, who saw a need for automation in mineral processing. Their specific objective was to beneficiate copper ore by desulfurizing and agglomerating it for copper blast furnace smelting at the Cananea plant in Mexico1. Since their early development the process expanded widely in scope, size, and application. The current worldwide sintering applications exceed 250 million tons per year for agglomerating ores of lead, manganese, zinc, and iron. Sintering is also widely used for production of sintered lightweight aggregate from clays, shales, and fly ash. The continuous sintering process took on wide expansion during the 1960's in foreign countries. Plants for production of approximately 135 million tons per year were built in these countries for sintering iron ore fines as shipped from new iron ore projects of Canada, Liberia, India, Brazil, and Australia. This expansion represented construction of approximately 80 new sintering plants, some as large as 15 thousand tons per day production on a single large sintering machine. Sized self-fluxing or highly fluxed sinter has become recognized as a premium blast furnace charge and has enabled blast furnaces of Japan and Europe to produce upwards of 10,000 tons of metal per day with coke rates less than 1,000 pounds per ton of metal. This coke requirement is practically 50 percent of the ordinary rates achieved during the early 1950's when the peak blast furnace production was less than 113 of the current records.

Jan 1, 1975

By R. E. Pennington

My subject this morning is coal liquefaction technology. Actually, coal liquefaction involves a number of technologies in a very complex system. The first slide shows the major components of such a system with arrows to indicate appropriate flows. The components are the facilities for coal feed preparation and handling; the coal hydrogenation or base liquefaction section; facilities for product separation and recovery, and in addition, facilities for the production of hydrogen from coal-based sources. A very rough break- out of the investments involved in these areas is given at the bottom of the slide. Investment is spread about equally among the three areas of operations Another way of looking at it is that the investments in what might be called support facilities are of the same magnitude as the base investment in the hydrogen facilities. Therefore, it is appropriate in a discussion of coal liquefaction technology to treat it as a system composed of a number of technologies. The next slide lists the various functions in the feed preparation section along with an indication of technology status. Storage, crushing, grinding, drying of coal all have been in commercial practice for a number of years. The slurrying and pumping of coal at least in water slurries, is practiced commercially also. The heating of coal slurries in oil to high temperatures under pressure is not in commercial practice and development and testing is going on by a number of people in this area. Some rather complex phenomena occur when coal oil slurries are heated to high temperatures.

Jan 1, 1975

By T. N. Andersen

The history of gold and silver analyses shows an interesting duality. On one hand, classical chemical and instrumental methods have evolved to meet changing needs, but on the other hand, the age-old and somewhat empirical fire assay has remained a popular tool. Inasmuch as gold and silver generally have been present in ores at low concentra¬tions, methods have been challenged by a need for sensitivity and selectivity coupled with reasonable assay time. A progressive increase in the importance of low grade materials as ore sources has led to the need for improved methods. Assays of these materials are required for process control and accounting in operating plants as well as for guiding research and development activities. The analytical response to these needs is evidenced by numerous reviews published through 1977-¬e.g., cf Kolthoff and Elving (1966), Beamish and Van Loon (1966, 1972, and 1977), Young (1971) , Mallett (1970), and Sen Gupta (1973). In this paper we present a brief sketch of the history and status of various gold and silver methods. A more detailed summary of atomic absorption spectroscopy (AAS) is Given, as this method has gained in popularity more than other assay methods. AAS methods currently in use are summarized and discussed briefly. This paper is not meant to be a detailed review, as are the above mentioned publications. Rather, we borrow from those works and more recent papers to report trends in gold and silver analyses (particularly in AAS). Also, we discuss some selected poten¬tial problems, and problems that have been experienced by this laboratory.

Jan 1, 1981

By Michael J. Pratko

The bulk handling industries have long been plagued with problems in their attempt to obtain one of their major goals - the maximum efficiency for which a bulk handling flow system was designed. Mentor Dynamics Ltd. is an international firm with offices in Canada, Japan, and the United States. Mentor Dynamics Ltd. is in the business of solving the "why not" of a system and engineers the solution for the problem. Studies of the varied difficulties encountered with bulk flow systems indicate that 90% of all flow problems fall into one or more of the following categories: abrasion, impact, sticking, and/or inadequate design. These problems can occur with a myriad of bulk solids: coal, gypsum, aragonite, phosphate, fly ash, ore. Solutions to the problems are as varied as the problems. The proper lining material, ceramic, urethane, rubber, and/ or ultra high molecular weight polyethylene, must be coupled with the correct fastening system, annular ring and 'F' cap, weld washer, button head fastener, weld studs and/or nuts and bolts.

Jan 1, 1982

By Frank Ruskey

Many problem associated with potential hazards in a proposed mining area may not be adequately appraised because of the complexity of trying to evaluate them in terms of production requirements. Frequently, encountered hazards have to be dealt with by day-to-day operational schemes that require the miner to either force a way through them or avoid them by blocking off the area in which the hazards are known to exist. These considerations, after the mine is in full production, can be costly to the mine operator and can increase the danger to the miners. A hazard-evasion computer program for mine planning that will appraise proposed mine layouts on the basis of existing or potential hazards has therefore been developed. The program is intended for use during the planning phase of a mine, where it should assist the mining engineer in making decisions in mine design. With the output from this program, the mining engineer should be able either to corroborate his judgments made on the basis of mining experience or to find unanticipated solutions to design problem. The program tests hundreds of possible solutions to a mining layout, and by sorting out the 10 best (based on a criteria of minimum-abandoned-coal) limits the number of choices that need to be considered and appraised for applicability to a given mine scheme.

Jan 1, 1973

By J. D. Pitts

The worldwide production of iron ores was approximately 880 million metric tons in 1975. This level is the result of an annual growth rate of nearly four percent during the period 1967 to the present. The high growth rate was particularly significant in that two relatively severe worldwide recessions occurred in 1971 and 1975. The current upturn in world economic growth will probably allow future annual iron ore production growth rates in excess of the four percent figure, and, in fact, the International Iron and Steel Institute (IISI) has predicted that a five percent rate should be realized through 1985. The IISI figures would indicate a 1.4 billion metric tons per year output by 1985 or an increase in current production levels of around 500 million metric tons per year (MMTA)1. Even the more conservative four percent growth rate prediction from historical data would provide an 2 increase over current figures of nearly 350 MA by 1985. A large portion of world iron ore production is being provided by large resource-rich countries with relatively new industrial bases. These countries are typified by heavy export of raw materials such as iron ore and ore products and a large capital investment in the facilities to recover these raw materials. Brazil and Australia are typical of such countries and, indeed, their production of iron ore in the period 1967 to 1973 increased at annual rates of 17 to 30 percent, respectively, The continual reassessment of resources in these and other major iron ore exporting countries such as Venezuela and Liberia would indicate chat these high growth rates may continue for some years to come to meet anticipated world demand for raw steel production.

Jan 1, 1976

By C. L. Wilsey, K. M. Oakes, W. J. Reich, M. J. Protani

The time frame required to complete the National Environmental Policy Act (NEPA) process for a new mine or the expansion of an existing mine can range from nine to 24 months, or even longer. The time frame will vary depending on whether an environmental assessment (EA) or an environmental impact statement (EIS) will be completed Completing properly designed baseline studies to collect natural resource data to support the EA or EIS prior to the start of the NEPA process can shorten this time frame. In this paper, a two-year natural resource baseline study by Homestake Mining for the Ruby Hill Mine, Eureka County, NV, is used as a case study to describe how a properly designed and executed natural resource baseline study streamlined the NEPA process.

Jan 1, 2003

By Ralf Plinninger, Pafos Busch, Richard Gradnik

This paper presents the details of the Bad Bergzabern tunnel project. This tunnel is the main part of the B427 federal road bypass, intended to improve the regional traffic infrastructure and to reduce the traffic load in the historic city centre of the health resort Bad Bergzabern. Located in the south-western part of Germany, the project area is situated at the eastern margin of the so-called Palatinate Forest, a low mountain region of mainly triassic sediments with a complex and variable geological history. The German federal government, represented by the office of mobility of Rhineland- Palatinate, awarded the contract to BeMo Tunnelling, a specialized Tunnelling company with a long history of innovation and success in NATM tunnelling. The contract includes the construction of two separate tubes with a length of approximately 1,44 km (0.9 mi)—the road (main) tunnel with a cross section of 101 m2 (1,090 sq ft) and a parallel rescue tunnel with a cross section of ca. 23 m2 (250 sq ft.) Both are connected by six cross passages. Tunnels and cross passages are excavated according to the principles of the New Austrian Tunnelling Method (NATM). Due to BeMo Tunnelling’s technical expertise and capabilities, the project team was able to engineer a speed-up concept that saves money and time for the construction team and client. This paper presents the innovative approach BeMo Tunnelling made to optimize the execution of the tunnelling works and the challenges the project team is facing with regard to a complicated geological situation, countermeasures against an increasing effect of climate change and volatile prices for construction materials.

Jun 13, 2023

By E. W. Geist

This paper is presented from the viewpoint of the mill operator and maintenance supervisor. Its purpose is to highlight the things that have been accomplished by the mill designers to lighten the load for the maintenance superintendent and to reduce the overall costs for the plant operator. The complexity of plant design, the civil and structural engineering problems encountered when the satisfactory maintenance layout is accomplished are appreciated, and the writer is fully aware of the complexities of these problems. However, it is not the purpose of this particular paper to dwell upon these problems, nor to emphasize or de-emphasize the problems of the civil, mechanical and electrical engineers. It is simply that the paper will attempt to review what these people have accomplished in spite of the many technical problems. This paper then is prepared with the operator and maintenance people?s viewpoint. What is their definition of design for maintenance? It is the writer's interpretation that the various design concepts which mean improved maintenance are such items as (I) maintenance areas, (2) laydown space for maintenance materials in specific maintenance jobs, (3) the inclusion of bridge cranes in the plant and specific design of the craneways to accomplish flexibilities for the cranes, and (4) the location of the piece of equipment to allow maintenance people to work around the equipment - - - this specifically includes the orientation of the particular piece of equipment.

Jan 1, 1967

By T. Harris

Exports of crude gypsum from Mexico currently comprise about 60% of all domestic shipments, and about 25% of the imported material consumed in the U.S. wallboard industry. However, of growing importance are the domestic markets for calcined gypsum in Mexico including building plasters and wallboard, which account for 55% of the internal demand for natural mined material. This paper will examine the current trends in the production and trade of natural mined gypsum in Mexico and North America and the opportunities and threats that are facing existing and new suppliers in this changing market.

Jan 1, 1996

By D. J. MacKinnon

Smooth, compact, dendrite-free, 24-h zinc deposits have been electrowon from zinc chloride electrolyte using a diaphragm cell. The cell consisted of sealed anode compartment con- taining DSA anodes which were separated from an open cathode compartment by Dynel cloth membranes. Fresh electrolyte was fed to the cathode compartment where zinc deposition onto an aluminum cathode was aided by air-sparging. The catholyte passed through the diaphragm into the anode compartment from which chlorine gas and spent anolyte were withdram.

Jan 1, 1980

By George Joseph Malina

Contractor chose and Owner allowed concrete to be placed using the arch first principle while excavating the 35'-3" O.D. rock tunnel. The contract included excavating and lining 26,000 L.F. of rock tunnel to 33'-I.D. Concrete was placed at a rate of 90LF per working day using a movable bridge to allow batching, mixing and pumping of concrete adjacent to the tunnel form.

Jan 1, 1981

By M. Karmis

Subsidence planning and control must be an integral part of mine design in order to minimize the economic impact of underground mining on the surface. Pre-calculation of surface deformations which may cause damage to surface structures must be performed and dam-age criteria must be established, if the response of structures to such movements is to be determined and the extent of damages to be assessed. In this paper the Surface Deformation Prediction System (S.D.P.S.), which can be used to predict accurately the vertical and horizontal parameters of surface movements due to underground mining, is discussed. The Subsidence Response Modeling Program (S.R.M.P.). which can be applied to evaluate the response of buildings to subsidence-induced movements, is also reviewed. Finally, an example is presented demonstrating the applicability of these techniques for subsidence design and control.

Jan 1, 1990

By T. R. Ellis

Many appraisers/valuers believe that the only valuation method available within the Cost Approach category for Real Property appraisal is the depreciated replacement cost method. Some valuation and financial reporting standards setters also believe the same. This paper introduces the minerals appraiser to a number of useful methods for mineral property appraisal that are based primarily on the principle of contribution to value, the predominant economic principle in the cost approach. Most of these cost approach methods discussed are primarily for use in valuation of exploration tracts and resource properties that have no defined reserves. However, the powerful rural cost method can be used to calculate the contribution of categories of resources, reserves, and other property components to the value of a mineral property. This method can be applied to mineral properties at all stages of development, including producing properties.

Jan 1, 2011

By R. A. Bilonick

Sampling is used in all scientific, engineering, marketing, and financial disciplines. The scientific theory of probabilistic sampling is a well established field, providing a general framework for basic methods that can be applied in fields that would appear to have little in common. The revolution in sampling occurred, in part, as a response to the need for quality control in industry during the Second World War. Since this time probabilistic sampling methods have been replacing pre-scientific non-probabilistic methods of sampling. This has not been the case, however, in the mineral industries in the United States. No general agreement on a theory applicable to all sorts of particulate materials has been reached. As a result, non-probabilistic methods are still widely used and the measurement of sampling precision - the hallmark of scientific sampling - is unknown. Much of the research on particulate material sampling that has been carried out over the last 40 years can be characterized by a lack of theoretical reasoning and rigor, an unwillingness to acknowledge previous work, and a lack of integration with existing, established scientific sampling theory. Non-standard statistical terminology is used and often standard statistical terms are misused. The confusion that has resulted is reflected in ASTM and IS0 sampling standards and in the practice of particulate material sampling.

Jan 1, 1986

By Paul R. Wieber

This paper describes the U. S. Energy Research and Development Administration's (ERDA) program to develop in situ coal conversion processes, especially gasification, he potential of this technology, the technical directions being explored, and the program strategy to carry the process concepts toward commercialization are emphasized. The geographic location of the U. S. coal resources and a market analysis are described. Commercially successful in situ coal processes could add over a trillion tons of coal to the U. S. coal reserves. The economics of these processes is compared with surface gasification independent studies show this process to be 25Z cheaper than surface gasification for Western coals. The major projects are briefly described. The Linked Vertical Well process is in the lost advanced stage and shows great promise. The last test produced a low-Btu gas averaging 171 Btu per standard cubic foot for average pro¬duction rates of 5.5 million standard cubic feet per day. The other projects are Packed Bed, Longwall Generator, and Steeply Dipping Beds.

Jan 1, 1977

By Robert D. Coyle, David L. Emmons

Introduction The Cove gold-silver deposit is located in Lander County, NV about 50 km (30 miles) southwest of Battle Mountain, NV (Fig. 1). The deposit is in the north-central part of the Fish Creek Mountains within the McCoy mining district. Gold was first discovered in the McCoy district in 1914 by Joseph H. McCoy (Vanderburg, 1939). From 1928 to the early 1930s, minor production occurred from shallow underground workings. Total gold production was less than 311 kg (10,000 oz; Stager, 1977). The district was inactive until the mid-1960s when it was explored by Bear Creek Mining, Summa Corp., Houston Oil and Minerals Corp., Gold Fields, and Tenneco Minerals. Tenneco began a detailed reevaluation of the McCoy deposit in the fall of 1984. Tenneco's decision to place the deposit into production was based on a geological reserve of 8.7 t (280,000 oz) of gold (Kuyper, 1987). Subsequent exploration and development drilling of the McCoy skarn deposit has more than doubled the mineable skarn reserves to 19 t (615,000 oz) of gold. In September 1985, Tenneco began development work on the McCoy gold-skarn deposit. The project is an open-pit, heap leach mine. The first gold was poured in April 1986. Echo Bay Mines acquired Tenneco's precious metals properties in October 1986. The mining operation and district exploration started by Tenneco is continuing under the Echo Bay's ownership. The Cove deposit was discovered in January 1987 and production began in February 1988. The deposit will begin as an open-pit, heap leach operation. It will be converted into an open-pit and underground mine with a 9-kt (10,000-stpd) mill. Geologic setting The Cove gold-silver deposit is situated on the east flank of the Fish Creek Range. Surface elevations range from 1460 to 1680 m (4800 to 5500 ft). The deposit is 1.6 km (1 mile) northeast of the McCoy gold-skarn deposit. The Cove deposit is hosted by the Augusta Sequence of Triassic age. Three formations of the sequence are mineralized at the Cove. In ascending order they are the Favret, Panther Canyon, and Augusta Mountain formations. The Favret formation is a gray, locally silty limestone that is commonly fossiliferous. The base of the formation is not exposed. Exposed and drilled intervals are more than 60 m (200 ft) thick. Conformably overlying the Favret formation is the Panther Canyon formation. This formation is 215 m (700 ft) thick and consists of a siliclastic and carbonate sequence of conglomerate, quartzite (sandstone), mudstone, limestone, and dolomite. It is a distinctly coarsening-upward sequence of rocks. The top of the unit is conglomerate with chert and quartzite clasts up to 150 mm-diam (6 in.-diam). The Augusta Mountain forma-

Jan 8, 1988

By A. M. Gaudin

In the first place, let me thank you for inviting me to appear before you today to speak to you on "Mineral Industry Problems - Present and Future". It is a distinguished honor for me to have this opportunity, and I am highly appreciative of this distinction. The beautiful surroundings of Gatlinburg and the pleasantness of a summer occasion are a wonderful tonic for all of us, yet they should not blind us to the seriousness of our Industry's problems No doubt, because of my past appearances before members of the Society of Mining Engineers, at which I discussed wholly scientific topics, or research in the Applied Sciences, you may be expecting me to revert to these subjects. But I intend to venture in a field that is new to me, yet old to all of us, the field of Economics.

Jan 1, 1962

By Ian Farmer, Nigel Glossop, Philip Garritty

Performance of tunnel boring machines - usually expressed in terms of penetration per revolution - is determined by relations between machine thrust and torque, head diameter and rock strength. It can be shown that for a given machine power and head diameter there is only one rock strength at which the machine performs optimally. In weaker rocks the available torque limits performance and in stronger rocks, the available thrust. Performance data shows that, historically, machines have been designed to cut weaker rocks. Optimization of thrust is required to improve performance in stronger rocks.

Jan 1, 1987

By H. Staton, N. Michaelson

"INTRODUCTION Lundin Mining’s Eagle Operation, located in Marquette County, upper Michigan consists of a mine and concentrator that process a Ni-Cu-(PGE) ore. The mine itself is an underground operation and the ore is trucked from the Eagle mine site 66 miles to the Humboldt mill where both nickel and copper concentrates are produced. Operations began in 2014 and continued with an average production of approximately 23,000 tonnes of Ni and 20,000 tonnes of Cu per year for the first three years of operation. The Humboldt Mill, currently operated by Lundin Mining, processes the nickel/copper ore from Eagle Mine and performs the concentration through several stages of flotation. Originally built in 1954, the Humboldt Mill began operations as an Iron Ore processing facility, and was converted to a gold processing plant during the 1980s. Various groups owned the site after closure of the gold operation. Eagle purchased the Mill in 2008 and invested more than $280 million to clean up historic mine waste and refurbish the plant (see flowsheet in APPENDIX). This paper will overview the ramp-up of the operation, and discuss some specific areas that went well and some that could have gone better during the design phase. HIGH LEVEL DESIGN CRITERIA Coarse ore arrives from the mine and is stored in a building with a capacity of 10,000 tonnes. Ore is crushed in three stages to a final product size of 100% Passing 12mm. Crushed ore is conveyed to the mass flow fine ore bins, which have a live capacity of 3000 tonnes. Crushed ore is fed to two parallel 900 HP ball mills, charged with 3” high chrome grinding media, and ground, in closed circuit with hydrocyclones, to a p80 of 110 microns in the flotation feed. Soda ash is added to the mills based on process water hardness. Cyclone overflow passes to the bulk conditioner where Sodium Isopropyl Xanthate (SIPX) and Methyl Isobutyl Carbinol (MIBC) are added. The slurry is pumped to the rougher bank for bulk flotation. Rougher concentrate is fed to a 500HP vertically stirred regrind mill and is ground to a p80 of 50 microns, using 5/8” high chrome balls. Rougher tailings report to the tailings thickener. The regrind cyclone overflow is sent to the single stage cleaner bank followed by two scavenger banks. The cleaner concentrate is pumped to the copper-nickel separation circuit. Cleaner tailings report to the tailings thickener. In the copper-nickel separation circuit, the pH is raised to 11.5 and a copper concentrate is recovered from the bulk cleaner concentrate in two stages, namely the copper roughers and the copper cleaner columns. The concentrate from the copper flotation columns is the final copper concentrate. The tailings from the columns return to the head of the copper-nickel separation. The nickel concentrate is the copper rougher tailings stream."

Jan 1, 2018