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By R. L. Atwood

This paper discusses the metallurgical and Manufacturing input to Merrill-Crowe plants. Topics treated are pregnant solution chemistry, clarification, degassing, zinc addition, product filtration, accounting, and costs.

Jan 1, 1985

By W. L. Wilson

This article could be entitled "The Rediscovery of the Windfall Mine," since it was originally discovered early in this century. The "Rediscovery" was made by personnel of Idaho Mining Corp. during the course of an investigation of the Windfall mine beginning in 1967. There had been historic production from the Windfall mine sporadically from 1908 until 1951 and there was present during much of this time a mill that vat leached crushed ore. Mining was underground to a depth of 91 m (300 ft). Prior to Idaho's activities, the mine had been inactive since the early 1950s. Idaho Mining Corp. was an "exploration company," privately owned and based in Reno, NV. The writer was at that time manager of exploration for Idaho Mining. The company held interests in the Cortez Gold mine, then being readied for production, and had conducted exploration for various mineral commodities in Nevada for several years. Idaho's attention was first directed to the Windfall mine in the Eureka District, Eureka County, Nevada (see Fig. 1, Nevada map) by a search of published geologic literature of the state of Nevada. An attempt was made to acquire a library consisting of all of the published geo-data for the state of Nevada as well as to obtain as much of the unpublished material as could be acquired. A study of these data, and in particular Tom Nolan's Professional Paper 406 (1962), indicated that the Windfall mine was anomalous for the Eureka District in that it contained deposits of disseminated gold. This source and other sources indicated that the Windfall had produced from underground operations approximately 59 kt (65,000 tons) grading 12.6 g/t (0.368 oz per ton) gold ore that was processed in a vat leaching operation and that the gold was "invisible" to the naked eye and could not be panned. It was ascertained that there were no active operations near the mine and a geologic reconnaissance was made and a few samples were taken to attempt to determine if the mineralization was indeed disseminated. The initial group of samples around the mine area averaged 1.25 ppm [11.5 g/t gold (0.036 oz per ton)] and the mineralization did appear to disseminate into the wallrock. The next step involved researching the ownership of property in the immediate area of the mine, and [ ] a property map was constructed that showed six or seven different ownerships of patented and unpatented claims, as well as some open ground, in the target area. Negotiations were commenced with the claim owners, ultimately resulting in the acquisition of all of the desired property, although some of

Jan 1, 1990

By Mahmut Altiner

Magnesium is listed as a key critical raw material in a report by the European Commission that evaluated raw materials based on supply risk versus economic importance [1]. It has extraordinary properties, such as nontoxicity, inertness, high melting point, stability, low weight, chemical resistance, electrical insulation, optical transparency, corrosion-resistant behavior and refractory nature. It is widely used in the areas of agriculture; the environment, for antibacterial and water-purification purposes; electronics; automotive; drug delivery; ceramics; construction, as filler in brick; and concrete production, in the forms of magnesium oxychloride and magnesium oxysulfate. Magnesium oxide (MgO) particles can be produced through the calcination of magnesite ore at different calcination conditions depending on the desired quality of the product, classified as fused (2,800 °C), dead-burned (>1,400 °C), hard-burned (1,000–1,400 °C), or light-burned MgO (700–1,000 °C) [2]. However, the global availability of magnesite ore is limited.

By Henry Brehaut

The International Network for Acid Prevention (INAP) was formed in 1998 by 17 international mining companies to promote significant improvements in the management of sulphidic mine materials and the reduction of liability associated with acid drainage through knowledge sharing and research and development of technology. Since its inception two panels have been formed to identify and move forward with research projects and eight networks have been constituted to initiate interaction and knowledge sharing within the membership in specific areas of technical interest. An INAP web site has been developed to facilitate the sharing of information and to encourage the exchange and development of new ideas.

Jan 1, 2000

By Ali Soltani, Scott Santti

The Gold Quarry Mine is a large scale open pit mine located 11.3 km (7 miles) north of Carlin, Nevada. The operation consists of an open pit mine, two milling facilities, a leach crushing plant, and three dump leach pads. Gold Quarry is operated by Newmont Gold Company, which is 90.1% owned by Newmont Mining Corporation, a Denver based company. The property is the largest of the three gold producing properties operated by Newmont Gold Company on the famous Carlin Trend. This paper will give a general overview of the Gold Quarry mining facilities and detail mine operating practices. Specifics on cost saving ideas being implemented and those under investigation will be discussed.

Jan 1, 1989

By Robert A. Jankowski, J. Drew Potts

By implementing various mining practices, mine operators can reduce the respirable dust exposure levels of the roof bolter and the continuous miner operators. The Bureau of Mines has developed a computer program, entitled AMP (Alternative Mining Practices), that gives a quantitative comparison of these reductions. The alternative mining practices and their corresponding reductions in dust exposure levels that are evaluated by the program include a remote control continuous miner, a half-curtain ventilation system, two auxiliary fan-tubing bypass ventilation systems, a modified cutting sequence, a comparison between single-split and double-split ventilation networks, and a comparison between exhausting brattice and exhausting tubing. Descriptions of each of these mining practices are included in the report. The report also includes a hypothetical case study to show how AMP enables mine operators to select the technique(s) that is best suited to their particular needs. AMP is a compiled basic program that has been designed to run on computers with a DOS version 2.0 or later operating system. It includes high resolution graphics (640 X 200 dot positions) designed to run with video boards that are functionally compatible with the IBM Monochrome/ Printer Adapter. Graphic screens are selected from menus, and can be bypassed if the computer is not equipped to handle high resolution mode. Their primary function is to show proper implementation of the mining practices evaluated by the program. This package requires a minimum of 256K bytes of RAM. (Reference to specific products does not imply endorsement by the Bureau of Mines.)

Jan 1, 1987

By H. V. S. Tingley, D. Helfant Ghose

"Ten years ago," said a mining industry personnel manager, "we used to wine and dine new mining engineering graduates. Now I can pick and choose among men with 10 years of experience." Comments like that are common throughout the industry today. During the 1970s, the US and Canada did indeed suffer from a severe shortage of mining engineers, especially experienced ones. Moreover, it seemed likely this North American shortage would worsen. Increased production of minerals and coal was pushing demand for mining engineers upwards, and there appeared to be substantial new employment prospects for them in the nascent synfuels industry. The oil majors entering the mining industry were pushing for an increased professionalization of mining management, heralding a trend towards higher intensity in the use of mining engineers. In response to the shortage, mining schools expanded their programs dramatically. By 1982, American schools were churning out more than 600 new mining engineers per year, compared to barely 200 in 1970 (Table 1). The timing of the explosion in the number of mining engineers could not have been worse. The downturn in the economy and the resulting slump in the mining industry coincided almost exactly with peak output of mining engineers. The market for mining engineers shifted from shortage to surplus with startling rapidity. The new crop of engineers, no longer courted by the mining companies, struggled to find any mining jobs. At the same time, experienced mining engineers found themselves thrown into the job market, some for the first time in decades. The current oversupply of mining engineers is assumed to be a temporary phenomenon. As the economy recovers, the demand for mining engineers is expected to pick up at least enough to absorb today's surplus. Not so, according to a recent study by Fenvessy and Schwab, a general management consulting and executive recruiting firm. In 1979, Fenvessy and Schwab was commissioned by a group of major mining companies to conduct a worldwide study of supply and demand for mining engineers to the year 2000*. The study began at the height of the North American shortage. One major objective of the study was "to identify means by which business and educational institutions may cope with and alleviate a future shortage of mining engineering talent." The findings, however, ran directly counter to expectations. The current oversupply will not disappear with economic recovery, the study concluded. In fact, the US and Canada are facing a massive oversupply that will probably last until the end of the century, unless enrollments in schools are reduced. Study Method Fenvessy and Schwab's conclusions are based on supply and demand models for mining engineers that it developed in the course of the study. Specifically, predictions for the supply of mining engineers are based on a survey of the 54 mining schools that account for about 90% of the world's annual output of mining engineering graduates. This survey asked for data on historical and projected number of graduates, obstacles to further expansion, changing trends in the use of mining engineers, and graduate career patterns. Fenvessy and Schwab developed three mining engineering supply scenarios from the survey data. The high case, considered unlikely for most of the industrialized world, is based on a continuation of the 1970's soaring growth rates. The middle case was established from the mining schools' own estimates of future growth in the number of graduating mining engineers. Finally, a "low growth" case for the US and Canada assumed that the number of graduating engineers will remain at current levels. Mining engineering demand was forecast using a complex model based on the demand for 50 major minerals. Formulas were

Jan 9, 1983

By A. Ligorio Pires de Carvalho

The main potash deposit at Taquari-Vassouras is contained in cycle VII, and consists of several sylvinite bodies. Cycle VII belongs to a sequence of nine cycles defined by Szatmari (1974) in the Sergipe-Alagoas basin. The sylvinite layers are separated by halite beds. They are seated on or may be laterally in discordant contact with other lithologies such as the tachyhydrites at the base, and the limestone breccia at the top. The main structural features in the deposit include numerous synclines and anticlines, salt dissolution phenomena, and open fractures associated with the axes of the anticlines.

Jan 1, 1995

By P. Corser

Operational and geotechnical constraints on mining within steeply dipping deposits and historic landslide areas, which are characteristic of subarctic coal deposits in Alaska, will be discussed. The current plan for mining through these areas will be presented, as well as an alternative plan for minimizing the adverse effects of mining through an historic landslide area.

Jan 1, 1988

By Klaus Rabensteiner, Klaus Chmelina

"INTRODUCTION Urban tunneling is often related with special geotechnical risks. Typical causes are difficult (hydro)geological conditions, a very low overburden and the presence of critical and vulnerable (infra)structures in the influence zone of the construction (e.g. existing tunnels, roads and pavements, sewer pipes, gas and power lines, landmarked buildings, historic monuments). To manage these risks appropriately, an early detection and warning of unexpected behavior of the affected geotechnical objects ground and tunnel, as well as existing structures are mandatory. To accomplish this, the design and execution of a dense geotechnical monitoring program is of high importance. In more detail, this means specifying and performing a systematic and continuous acquisition, processing and analysis of monitoring data to support decision making. In recent years the development of new automatic sensors and (wireless) data transfer techniques and the general trend towards an automatic acquisition of monitoring data has led to an enormous increase of data production frequencies and volumes. In order to handle this data explosion efficiently, information systems and geo-databases have been developed and used successfully in many projects. They represent IT tools that support the different tasks of a given geotechnical monitoring program including data acquisition, transfer, check, processing, backup, analysis, distribution, reporting and, last but not least, alarming. Meanwhile, some tools already have developed the capability to connect to other theme-specific databases used in the project and, thus, serve as a central data management system for all kind of digital data produced. This makes possible the implementation of further useful functions and services supporting tunneling tasks such as machine control, tunnel simulation, geological prediction, process optimization, etc. where data from different engineering disciplines must be combined and processed in an integrated way. In the following chapters our aim is to describe how monitoring data management, geotechnical monitoring, alarming and reporting are organized and technically implemented at the metro project Cityringen in Copenhagen (Denmark). We want to highlight the specific role and tasks of the used tunnel information system in the project, and particularly inform on the most relevant challenges."

Jan 1, 2016

By J. E. Garlanger

Each year, Florida mines approximately 40 million tons of phosphorite, most of which is ultimately converted to various commercial fertilizers. The phosphorite is mined from within the bottom portion of the 40-to 60-ft. thick surficial aquifer, using open pit mining techniques. The ore zone or "matrix" is generally overlain by relatively permeable fine sand to silty and slightly clayey fine sand. The ore itself is highly variable in nature but, in Central Florida, typically consists of less permeable clayey phosphatic sands and sandy clays with stringers of permeable sand. The ore is much more sandy in the north Florida mining area.

Jan 1, 1990

By Ward Sumner

The Jones Hill prospect is a Proterozoic age, volcanogenic, semi-massive to massive sulfide deposit. The deposit is located on the western edge of the Pecos greenstone belt in the southern Sangre de Cristo Mountains of northern New Mexico. The prospect is found in a block (West Block) of meta- igneous rocks, primarily diabase, metavolcanic rocks, and metasedimentary rocks (fig. 1). This assemblage is typical of lithologies found in the greenstone belt. Metamorphic grade is greenschist to lower amphibolite. The West Block is bound- ed on the west by Proterozoic age (1.7-1.4 b.y. by Rb/Sr), granitic plutons collectively called the Embudo granite, and on the east by Paleozoic sedimentary rocks, primarily sandstones, shales, and limestones of Mississippian and Pennsylvanian age. The mineralization occurs in a single horizon which has been overturned and cut into two blocks by a high-angle reverse fault (fig. 2). The mineralized horizon is found at the contact of felsic metavolcanic and rnetavolcaniclastic rocks with overlying intermediate metasedimentary rocks. The local stratigraphic sec- tion from bottom to top is as follows: 1) porphyroblastic quartz- sericite schist (originally a rhyolitic, subvolcanic intrusive); 2) quartz-sericite-chlorite-biotite schist (felsic metavolcanic and metavolcaniclastic rocks); 3) chlorite-talc-biotite-sulfide schist (altered felsic metavolcanic rocks); 4) carbonate-quartz-sulfide [ ] chlorite-tremolite-talc schist (mineralized exhalite); 5) quartz- chlorite schist (silicified tuff); and 6) amphibole-chlorite-feldspar- biotite schist (occasional mafic to intermediate metavolcanic flows).

Jan 1, 2013

By John D. Kalasky

Island Creek Coal Company has had, for many years as a primary concern, the activity of handling large quantities of methane in the ventilation of its deep mines of southwest Virginia. Since the development of the Beatrice operation in the mid 19601s, the concern has been well founded, and through the years progress has been made in this most important facet of the extraction of the coal reserves to insure the safety of the employees engaged in the mining opera- t ions.

Jan 1, 1980

By Axel Nitschke, Josef Arnold

Bochum’s Underground Lot 306 was characterised by a confined site and unique tunnelling methods. A highly mechanized construction concept was developed to achieve high progress rates. Bespoke backup systems for muck disposal and material supply were used. For the first time in suburban tunnelling, wet shotcrete, batched onsite, was applied. A three-storey underground car park had to be undermined with only1.5 m of overburden and had to be lifted several times by “compensation grout in.” An existing operational two-lane metro tunnel was enlarged without any major impact on train operation.

Jan 1, 2005

By Gary F. Rajala, Bruce R. Greenwood

INTRODUCTION The Empire Mine is an iron ore mining, concentrating and pelletizing facility operated by The Cleveland-Cliffs Iron Company in the Upper Peninsula of Michigan. Owners of the mine are Inland Steel, LTV Steel, Wheeling-Pittsburgh Steel and Cleveland-Cliff s. The orebody is a fine-grained, low grade iron formation with magnetite as the primary constituent. Also present are iron carbonates, iron silicates, chert, hematite, goethite and quartz. The original six concentrating lines were started in late 1963. Successive expansions of ten lines in 1967, five lines in 1974 and 3 lines in 1979 have resulted in Empire reaching a present annual capacity of 8.0 million long tons of pellets. The Empire flowsheet was developed over several years of laboratory bench testing, pilot plant testing and testing of a full-scale primary autogenous grinding circuit. Since the original flowsheet was established, modifications have been made based on pilot plant and full-scale plant tests. The present flowsheet for three sections of the concentrator consists of one stage of crushing, two stages of closed circuit autogenous grinding, two stages of magnetic separation, one stage of hydraulic concentration and two stages of flotation (rougher and scavenger). The flowsheet for the fourth section of the concentrator (Empire 4) is the same as the first three sections, except a crusher has been added to crush excess pebbles. The Empire 4 flowsheet appears in the at- tached figure. PRIMARY GRINDING CIRCUIT FLOWSHEET Empire has a total of 24 individual grinding lines. However, at the present time, Line 1 is not being used for processing crude ore. The primary mill on Line 1 is now grinding flux stone for fluxed pellet production and the secondary mill is being used as a ball mill to grind rougher flotation tailings prior to a scavenger flotation circuit.

Jan 1, 1992

By Dilip I. Patel, Jesus Schabib, W. Allen Mawr, Daniel A. Louis

East Side Access (ESA) will extend Long Island Rail Road into midtown Manhattan via 11 km of tunnels, a new terminal station and associated rail support facilities. The hard-rock tunneling in Manhattan will traverse under Park Avenue and some of the most historically and commercially significant real estate in the world. The soft-ground tunneling in Queens will traverse beneath Amtrak’s Sunnyside Yard and the Harold Inter locking, the busiest rail interlocking in North America. This paper details ESA’s program-wide geo-instrumentation monitoring system for obtaining, processing and presenting all geotechnical monitoring data. Data streams will be real-time, such as from automated total stations, and manually read, such as from optical survey instruments and handheld data loggers. All data will be input into a web-based Geo-Instrumentation Data Management System, which will be accessible to project stake holders via ESA’s intranet or via the Internet using remote access controls.

Jan 1, 2007

By R. A. Bergman, P. G. Thornhill

Development of the Falconbridge Ferronickel Process for treatment of lateritic nickel ores began with laboratory work in 1955, the year the Company commenced exploration of its concession in the Dominican Republic. Process development centred on selective reduction originally directed to producing calcines amenable to ammonia leaching, but later found suited to electric smelting. The reduction step of the process was developed in a 25 tpd shaft furnace pilot plant located in the Dominican Republic, to which was later added an electric melting furnace. After almost 3 years of development work on this scale the plant was expanded to 100 tpd for fixing design data for a commercial plant. This took the form of the 30,000 ton per year Nickel Ferro-nickel Complex of Falconbridge Dominicans, which started up in 1971.

Jan 1, 1979

By L. O. Bond

High costs--and high risks--are normal in coal exploration and mine development. But risks and ultimate costs are minimized by foreknowledge of prospective coal seams and adjacent formations. Extensive drill hole programs are often used to obtain needed information. Cores and cuttings from these holes are used to determine coal location, thickness, and quality; they are also used to study physical and geological characteristics of surrounding beds. Valuable as these core and cuttings studies are, their effectiveness is often diminished by loss of recovery or by incomplete analysis. Needed is an effective and economical method for augmenting these studies. Well logs provide information of the type needed for efficient cool prospecting. Furthermore, obtaining these logs in drill holes, and evaluating the data they provide, is both fast and economical. To investigate the usefulness of well logging methods in coal explorations, the authors worked with Mr. Jon Jenkins of Truax Truer Coal Company. Logs were run in a number of drill holes in various areas of the Illinois Basin; these areas provided variety both in coal quality and geologic conditions. The data were studied extensively using computer methods similar to those now used in the evaluation of oil and gas wells. (2, 3) This study was used to produce a computer-generated analysis designed especially for mining problems.

Jan 1, 1969

By Frank F. Aplan, Edward C. Dowling, Richard R. Klimpel

Several series of time-instantaneous samples were taken on a cell-by-cell basis in the flotation circuits of the Pinto Valley, AZ copper concentrator. These samples were used to calculate mass flow rates throughout the circuit using standard, deterministic metallurgical formulae and also a variety of more statistically oriented techniques. Because of the magnitude of the errors associated with the individual cell samples, the standard metallurgical formulae are not sufficient. Consequently, it is necessary to utilize some type of statistical technique capable of distributing the individual cell sample errors in such a way so as to provide a physically useful mass balance for the entire circuit. This paper explores the use of linear and least squares programming as one technique to providing credible mass balance calculations. For linear programming this was done by distributing the error using two different criteria involving specific linear programming formulations: least absolute sum minimization (which assumes an underlying double exponential distribution error structure) and minimax (which minimizes the maximum absolute deviation and assumes an underlying rectangular distribution error structure). These results were then compared to the more standard formulation of minimization of the sum of least squares which assumes an underlying normal distribution error structure. The least absolute sum approach was particularly attractive due to its simplicity of use and the ease in which repetitive calculations can be done with no user intervention.

Jan 1, 1990

By S. Schina

Part of the Imittos Western Peripheral Motorway in Athens is the twin road tunnel in the vicinity of American College, with 20m excavation diameter. In the paper, the environmental and other requirements, the geometry and the geological – geotechnical characteristics of the rock formations in the construction area are given. Information regarding the modeling and analysis methods that are used for the design of the temporary support, the final lining and the wedge and slope stability analysis is described thoroughly. Finally, the results of the analyses are compared with these of measurements and general remarks during the construction of the tunnels.

Jan 1, 2001