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By J. R. Mattern

The engineering geology of the Rio Tinto Borax Boron Mine creates challenges in providing practical slope design recommendations to mine planning engineers. Low strength sedimentary units interbedded with very low strength lakebed clays surround the orebody. Faulting has offset and juxtaposed these units into variably adverse orientations, while groundwater is compartmentalized both vertically and horizontally within fault blocks. A collective program of geologic data collection, geomechanical strength testing, geologic modeling, slope depressurization, confirmation of underground stope locations, and documentation of slope behavior provides vital information for design investigations and sensitivities. Analysis results lead to risk assessments and operational procedures that add value to the business by optimizing slope configurations and minimizing risk.

Jan 1, 2004

By Giovanni Osellame, Jean Habimana

"The Montreal Metro Blue Line Extension Project is part of a metropolitan Program that was launched in 2009 by the Transportation Ministry of Quebec to add additional extensions to existing metro lines in the cities of Montreal, Longueil and Laval with the intention to meet current demand and future growth within the Montreal agglomeration. Specifically the Blue Line Extension Project will add five underground stations to the East of the Montreal. The paper addresses the preparation and the implementation of a three-step geotechnical and geo-environmental investigation program and preliminary design considerations such as the selection of a preferred horizontal and vertical alignment, the selection of construction methods based on previous local experience and current industry trends, as well as preliminary sizing of underground infrastructures. PROJECT BACKGROUND An agreement between the three mayors of the Montreal Metropolitan City agglomeration, namely, Montreal, Longueil and Laval prompted the Government of the Province of Quebec to create a project office to oversee the studies of extending the existing metro network. The last extension of the existing metro network was completed in 2008 with the Laval extension, which consisted of adding three stations from the existing Orange line. The current extension Program consists of three different extensions, namely extending the Orange Line to Laval and finishing the loop, extending the Blue Line to the East of Montreal by adding five stations, and adding five stations on the Southshore of the St-Lawrence River for the Yellow Line extension. The extension program also requires the construction of an underground storage and maintenance garage located to the north-west of the existing Cote-Vertu station on the Orange line. Figure 1 shows the overall extension program with the existing network."

Jan 1, 2016

By Charles N. Speltz

The cost of transportation of industrial minerals frequently is higher than the cost of the product. When a mine, industrial-mineral plant, or customer is served by a single railroad, because of the lack of competition, that railroad may in- crease rates and/or reduce service so that the economics of that mine, plant, or customer are affected adversely. Transloading of industrial minerals from rail-to-truck or truck-to-rail to improve economics and sales of product is not a new concept. However, transloading to create competition and reduce freight costs or to improve service is a relatively new concept brought on by the recent mergers of many of the main-line railroads, both in the eastern and western United States. For example, in 1998, with completion of the Burlington Northern/Santa Fe (BNSF) and the Union Pacific/Southern Pacific mergers (UPSP), the western United States has only two main-line railroads. The industrial-mineral producer, to reduce the cost of transportation or increase the level of service, must evaluate potential transloading opportunities in light of higher prices and reduced service brought on by reduced railroad competition. This paper discusses industrial-mineral transloading and examines the case history of the Tucker Hill perlite project in southern Oregon. The Tucker Hill project is a classic study of industrial-minerals transloading where the project would have failed without the transloading.

Jan 1, 1999

By Judith M. Ballantyne

Carlin-type. disseminated, sediment-hosted gold deposits can be better described as hydrocarbon-associated gold deposits. A new genetic model for these deposits involves the intrusion of one or more small bodies of magma into a shallow hydrocarbon reservoir or ma of hydrocarbonenriched rocks, imposing a convecting geothermal system on the local groundwater. Pyrite, commonly associated with the organic material, provides a substrate for deposition of gold and other trace elements in an environment rich in dissolved sulfide. Both diagenetic and hydrothermal pyrite may act as gold depositional sites. Thermal cracking of hydrocarbons, catalyzed by illite, subsequently generates an oxidizing environment by depleting hydrogen. As oxidation increases, arsenic sulfide minerals and barite m stabiied at first. Increasing hydrogen depletion converts sulfide to sulfate, generating acid oxidizing conditions which: alter pyrite to hematite; continue the deposition of sulfates; and ultimately develop late stage acid-sulfate assemblages containing minerals such as kaolinite. alunite. and jarosite. Gold released from the oxidizing pyrite is redeposited as free gold, and pehaps remobilized.

Jan 1, 1988

By Nicole R. Henderson

Many mining engineering graduates enter the mining industry lacking training in mine emergency management. As a result, mining universities in the United Sates and other countries are beginning to form volunteer student mine rescue teams to train mining engineering students in handling mine emergency situations and give them hands-on experience managing potential emergency scenarios underground. In the early 1980s, the Missouri University of Science and Technology developed the first collegiate mine rescue team in the United States. For approximately 30 years, it was the only successful collegiate team until the Colorado School of Mines (CSM) started its program in 2009. Currently, there are at least five collegiate teams in the United States and one in Canada. At the Freiberg University of Mining and Technology in Germany, the goal is to adapt the Colorado School of Mines Mine Rescue Program to develop a collegiate team of its own. Currently, mining engineering students cover the theoretical basics of mine rescue in an occupational health and safety lecture and take a basic, one-day mine rescue training course at the Central Mine Rescue Station in Leipzig. The course covers the basic mine rescue topics and gives students the opportunity to experience working in elevated heat and smoke conditions while wearing breathing apparatus. This training gives students a small insight into the importance of mine rescue and mine emergency management. Collegiate mine rescue teaches students the importance of mine rescue and mine safety by giving them hands-on learning experiences before entering the mining industry.

Feb 1, 2014

By Keith G. Wallace, Malcolm J. McPherson

In order to model accurately a mine ventilation system in an existing mine, it is necessary to determine the resistance to airflow in all main airways. This is accomplished by measuring the airflow and pressure differential in each airway. Gauge and tube methods have been used to determine pressure drops in ramps and level airways. However, it has rarely been used in evaluating the frictional pressure drop in shafts. Because shafts commonly have the highest pressure loss in mines, it is critical that the resistance of these airways be determined accurately. This paper describes the theory and practice of using the gauge and tube method for determining the pressure drop in shafts. The pros and cons of using this method are discussed as well as a comparison between the gauge and tube and barometer measurement techniques. Case studies showing the accuracy of shaft gauge and tube measurements are also presented.

Jan 1, 1991

By D. Constantinides

In 1981 a Zn-Ag-Pb deposit was discovered in the vicinity of Molai, Greece. Subsequently, it was determined to be of the Kuroko type. The geology of various areas in the southeast Peloponnesean Peninsula is similar to that of the Molai deposit. Since favorable geologic criteria are present, absent, or unknown in varying degrees in all areas, it was deemed necessary to classify and rank the prospective areas according to the level of information available. For each level of information, an ore discovery model based on pragmatic exploration criteria was developed, enabling the favorability of occurrence to be calculated for each area. A Monte Carlo simulation was used to calculate the probabilities, the input data consisting of quantitative and qualitative estimates of the geologic criteria for each area. Three levels of information were modeled : Level A consisted of 9 criteria, level B of 12 criteria, and level C of 20 criteria. The three levels of information were tested on the Molai area. The results exceeded expectations, showing the gen¬eral trends which control mineralization at the lowest level of information. With an increase in the level of information, geological trends become more evident and a differentiation can be made between areas containing Cu mineralization, exhibiting a low probability, and areas likely to contain Zn-Ag-Pb mineralization. The models were then applied to the neighboring areas - only level A and B were available.

Jan 1, 1986

By Walter Küng

The Henderson Coarse Ore Conveying System is a three flight belt conveyor system transporting primary crushed molybdenum ore 24 km (15 miles) underneath the North American Continental Divide. One of the conveyors is 16.8 km (55,200fi) in length with 8,200 kW (11,000 HP) of installed power. The overland conveyor contains 11 vertical curves and 9 horizontal curves, some with radii as small as 1,500 m. he system began full operation in December 1999 and is one of the longest and most complicated belt conveyor systems yet constructed. he design of this conveyor system utilized many innovative engineering concepts including low-energy belt covers, low-resistance idlers, torque-controlled tail drives, combined gravity and active winch take-up systems, small radius horizontal curves and belt turnovers. his paper reviews the start-up of the system, discusses the success of the design and addresses the lessons that can be learned from the first 4 years of operation of this unique conveyor system

Jan 1, 2004

By James R. Walsh

While flue gas scrubbing with alkaline solutions is one of the oldest methods of removing SO2 from flue gas, a satisfactory scrubbing system for this application, which is both technically and economically viable, has yet to be developed. Interest in alkaline scrubbing has continued because of its basic simplicity and comparatively low capital cost. Drawbacks of alkaline scrubbing are the tendency for accumulation of solids to plug the system, scaling, corrosion and erosion problems and the need to dispose of large quantities of waste. Discussed are instrumentation loop applications to a 90,000 cfm alkali scrubbing test facility, the process problems the instrumentation engineer faces in. selection of equipment, the performance of the instruments selected and the problems encountered during start-up. The Test Facility incorporates centralized electronic process control with a digital data acquisition system provided to log process variables and print off normal (alarm) conditions. Flue gas SO2 content is measured by ultra-violet analyzers and analysis of the total gas stream is by gas chromatographs.

Jan 1, 1973

By M. K. Patel, K. C. Wade, M. Cross

In the past decade a good deal of effort has gone into the computer simulation of the heat distribution of pellet induration systems. The major uncertainty in the analysis of such systems is the gas flow distribution and, in particular, the role of leakage. Evaluation of the leakage into or out of a zone has proved to be very difficult, as has the cross-flow from one zone to another when adjoining zones have gas flows which change direction from up draft to down draft for example. This paper describes an initial model to calculate the gas flow distribution in a variety of practical situations of interest to those involved in pellet induration. The model is based upon a multiphase CFD code called CASCADE which is used in conjunction with the pellet induration simulation INDSYS.

Jan 1, 1990

By Derek J. McCracken, William G. Holroyd

Emery is a rock that at one time held a large share of the abrasives market. The introduction of synthetic abrasives, however has forced it to settle for only certain niches in the marketplace. This loss of market share is due mainly to the higher amounts of impurities and weaker internal structure that naturally occurring minerals have compared to manmade materials. The use of rocks and minerals as abrasives dates back to early man, who used flint, quartz, and other natural materials to fabricate various tools. During the 19th century, with the Industrial Revolution imminent, the character of the abrasives industry was changed forever as synthetics were introduced. Frank B. Norton is credited with producing the first manmade abrasive when, in 1855, he manufactured a vitrified grinding wheel using emery grit and clay. Before Norton's accomplishment emery had been the only commercially available abrasive. The latter part of the 20th century has seen synthetics capture an increasing share of the abrasives market from natural materials. The term emery is believed to have been derived from the words emeri (French), smeriglio (Italian), and smiris (Greek). The term corundum, for the principal mineral of emery, seems to have originated from kauruntaka, the Indian name for the mineral. GEOLOGY Emery is a gray to black, granular rock comprised of various minerals including corundum (A1,0,), an iron-bearing mineral (usually magnetite-Fe,O,, hematite-Fe,O,, or hercynite- FeAI,O,), and several trace impurities such as mullite, titania, silica, and magnesia. The hardness of emery normally ranges between 7 and 9 on the Mohs scale, depending on its mineral com- position and level of impurities. Corundum, the hardest mineral in emery, typically has a hardness of 9. The specific gravity of emery ranges from 3.2 to 4.5, also depending on mineral composition and purity. The crystallography of each mineral contained in emery differs somewhat. Corundum exhibits an hexagonal crystal structure, whereas magnetite forms within the isometric system, frequently as octahedral crystals. Hercynite, an iron spinel, is also isometric. Hematite has an hexagonal structure but often is found as botryoidal and reniform masses. Principal deposits of commerical emery are found in the United States, Turkey, and Greece. In the United States two emery producers in the Westchester County-Peekskill area and one in the Cortlandt County area of New York closed their mines in the late 1980s. Commercial production in the United States now comes only from the western Cascade Range in Oregon. The emery in New York has a typical A1,0, content of 41.5%. Most of the rock is not true emery because it contains a mixture of spinel and magnetite but very little corundum. The deposits are of Late Ordovician-Early Silurian age and consist of veins in which emery is mixed with olivine, pyroxene, and hornblende. The veins evidently were formed by contact metamorphism and are surrounded by Precambrian schists that contain mica, sillimanite, cordierite, garnet, and quartz. The deposits in Oregon were formed during Miocene time by the contact metamorphism of ferrunginous bauxite by intrusive lamprophyric dikes and plugs. Emery is found in thin layers bordering these tabular dikes, which are usually oriented perpendicular to bedding, and in "surficial placer deposits. The emery deposits in Turkey occur as small, massive, lens- shaped bodies and as surficial placers. They are believed to have formed during Permian and Triassic times. In Greece the principal site of emery production is at Cape Emeri on the Island of Naxos. These deposits consist of lenticular masses of emery surrounded by marble. They originated during Mesozoic time, evidently by metasomatic replacement. Smaller deposits on several other Aegean islands were formed by the metamorphism of bauxite or other alumina-rich materials.

Jan 1, 1994

By M. Tarshan, M. C. Williams, T. P. Meloy

A methodology is presented for the spreadsheet solution of separation processing networks. With the methodology developed, a spreadsheet grid is used to represent networks both with and without recycle loops. In this manner, network solutions are numerically approximated by spreadsheet grid solutions. The methodology was used to explore the ramifications of networks developed by the Chinese for tungsten and molybdenum processing Nonlinear stage-transfer functions for two-component sharp separations can be used.

Jan 1, 1996

By L. B. Hales

The advent of the process control computer with its capabilities of monitoring, storage, and real-time control has revolutionized control technology in the mineral industry. Initial efforts to introduce the computer into process control began in the early 1960's. However, it wasn't until the last decade with the introduction of integrated circuits and minicomputers that truly successful applications became visible. Computer hardware and real-time operating software have improved to the point that they rarely provide major problems in the implementation of successful control systems. At this time the most prevalent problems and obstacles affecting the successful implementation of a control system are as follows: (1) reliable and representative sampling systems; (2) rugged and reliable process sensors; (3) the availability of well-defined control strategies; (4) the willingness of plant management to provide the continuous support necessary to acquire and/or train appropriate personnel in the operation and maintenance of advanced control systems. Discussion of these problems and of the instrumentation required for the successful application of computers in minerals processing plants follows. In order to enhance this discussion the remainder of this subsection is broken up into individual mineral processing categories.

Jan 1, 1979

By R. Schipper

Two bench scale biochemical reactors (BCRs) were operated over a period of 3 months for the removal of uranium, radium, and selenium from mining influenced water (MIW). A BCR is an anaerobic reactor comprised of organic and inorganic substrate including woodchips, straw, sawdust, and limestone. Uranium and selenium are removed in a BCR by biological reduction of oxidized species (i.e., selenite, selenate) to less soluble forms (Pahler et al. 2007, Blumenstein et al. 2008, Rutkowski et al. 2013). It is believed that radium may be removed through absorption to the biomass in the BCR. The bench scale BCRs were constructed of 6 inch PVC columns with a top to bottom flow configuration. The bench influent water consisted of three different water ratios from two adit seeps. BCR hydraulic retention times of 24 to 36 hours were targeted during the study. Influent concentrations ranged from 19 ug/L to 1.86 mg/L for dissolved uranium, 12 ug/L to 270 ug/L for dissolved selenium, and 4.9 pCi/L to 24 pCi/L for radium 226. The average and maximum dissolved uranium removal was 93.6% and 98.5% respectively, the average and maximum dissolved selenium removal was 93.3% and 98.9% respectively, and the average and maximum radium 226 removal was 89.5% and 100% respectively.

Feb 23, 2014

By A. J. Neale, B. C. Flintoff

A relatively inexpensive and reliable method of using liquid phase tracers to aid in the solution of material balance problems is introduced. The method is of value in situations where one is required to calculate a material balance around a process that has the operating appearance of a "blender" or "splitter" with respect to the available slurry sample data. The paper briefly reviews material balance development and tracer applications in mineral processing, introduces the problem to he addressed, and provides both theoretical and industrial evidence establishing the potential of the method.

Jan 1, 1987

By Janet E. Lamarre

Current statistics show that 90% of new-business failures are caused by the unsuitability of the entrepreneur for the business he has started. Are you a suitable candidate for success as a consulting geologist? Should you start your own geologic consulting business, and when? This paper investigates the demand for consultants with respect to general economic trends and mineral exploration activity trends. Furthermore, the study reveals certain technical skills and personal characteristics important to the success of the consulting geologist. Research shows chat certain expectations which prompted geologists to change careers are fulfilled while other unanticipated expectations often are also met.

Jan 1, 1985

By Hetland Donald L.

Regional Tertiary formations and basins of local sedimentation which contain uranium deposits west of the Rocky Mountains are mainly of Oligocene, Miocene, and Pliocene age (fig. 1). The host rocks have been derived mainly from intrusive and extrusive igneous rock. The major host formations which cover broad geographic areas include the Esmeralda, Truckee, Humboldt, Thousand Creeks, Payette, Panaca, Cedarville, Coso, and San Joaquin Formations. Local areas of Tertiary sedimentation containing uranium deposits occur near Yuma, Safford and Artillery Peak, Arizona; Dillon and Canyon Ferry, Montana; Spokane Indian Reservation and Pend Orielle River, Washington; Topaz Mountain, Utah; Stanley Basin, Idaho; and Sonora Pass, California. Uranium deposits in these sediments have been classified into five categories based on environment (fig. 2). They are: (1) Deposits in lake sediments consisting mainly of water-laid tuffs; (2) Deposits in lake sediments intruded by volcanic plugs; (3) Deposits in lake sediments interbedded with arkoses near batholiths; (4) Deposits in coarse volcanic sediments in local sedimentary basins; (5) Deposits in arkosic conglomerates in local sedimentary basins.

Jan 1, 1969

By Immo H. Redeker

Tile Asheville Minerals Research Laboratory is a member of the Engineering Research Department of North Carolina State University. The Laboratory is engaged mainly in applied nonmetallic mineral processing research to assist the North Carolina mining industry. A few out of state projects are handled at times. The Laboratory helped to bring the flotation process to North Carolina feldspar, spodumene, mica and phosphate producers and maintains versatile batch and pilot plant facilities at Asheville. It is of interest that North Carolina has now one of the newest and largest flotation plants at Lee Creek where Texas Gulf Sulphur Company produces 10,000 tons of phosphate concentrate per day, and one of the smallest flotation plants at Pittsburgh Plate Glass Company's fiberglass plant in Shelby, North Carolina where $50,000 per year of platinum-rhodium metal is reclaimed from wasted fiberglass furnace refractories in a tiny flotation operation of pilot plant size. The conservation of mineral resources through improved processing methods has been the object of most of the Laboratory's projects. This work has been extremely interesting and rewarding in many instances. Or, the example of projects for Kings Mountain Mica Company it will be demonstrated how waste could be reduced step by step from 20 tons of waste per ton of product to LO tons of product per ton of waste by improved processing methods. Brick, high grade potash feldspar, and silica sand are now produced from formerly wasted materials. AL this time Laboratory work sponsored by three feldspar companies, the State of North Carolina, and the U. S. Bureau of Mines, is aimed at reducing the amounts of feldspar tailings in the Spruce Pine area. Mineral dressing techniques are applied to reclaim saleable mineral products such as feldspar, mica quartz, and to make more uniform material for possible ceramic and other applications. Processes to produce new products such as sand-lime brick, and lightweight foamed autoclaved calcium silicate building products will be tested.

Jan 1, 1969

By F. Lincoln & B. Rodier, G. Poniatowski, N. Kawashima, T. J. White, J. H. Kyle, G. F. Eaton

The history of Australia is a narrative of the discovery and development of its mineral wealth. The gold strike at Ballarat, Victoria, in 1851 transformed the colony by triggering the first great influx of migrants to Australia, and the development of subsequent mineral discoveries lead to a vast resource industry. However, beneficiation of base and precious metal ores carried with it an environmental penalty, not addressed until the last quarter of this century. In particular, the extensive deposits of gold, silver, lead, copper and zinc reside in sulphurous ores which often contain arsenic, antimony and mercury as significant contaminants that are released as unwanted by-products during smelting and refining. Until recently, these toxic concentrates were discharged to the atmosphere or receiving waters, collected in tailings ponds close to the smelters, or dumped at sea. Although such procedures . were acceptable in the past, more stringent environmental controls have required a re-examination of these practices and encouraged intensive efforts to develop enduring solutions to the disposal of these wastes. From this research has emerged a promising new generic technology called Xtaltite (pronounced crystal-tight). In this approach, geochemical principles are employed, first, to reduce the toxicity of heavy metals to low levels, and second, to identify and engineer suitable repositories for the permanent disposal of the consolidated waste form. In this paper, we emphasise the application of Xtaltite to the disposal of arsenious smelter fumes derived from gold winning. The principles ofXtaltite will be described and its technical and economic performance compared with conventional technolo­gies.

Jan 1, 1995

By William G. Davenport, Eric H. Partelpoeg

Direct smelting of copper in a single vessel has long been the extractive metallurgist's dream. Such a process offers the important advantages of (i) maximum use of the energy available from oxidizing the sulphur and iron of the concentrate; (ii) restriction of SO2 emissions to a single constant-strength source; (iii) minimum materials handling and (iv) elimination of at least one process step. Extensive developmental work was carried out in the 1960's and 1970's to implement such single-step processes. Some of the processes reached the prototype stage and it appeared that copper smelting technology was on the threshold of a new, efficient, minimum-pollution era. Since that time, however, the forward thrust has slowed and single-step smelting is still a process of the future. The paper describes in detail the potential advantages of single-step smelting; its history and current status; and the reasons why it has not been adopted industrially. It concludes that the potential benefits of single-step smelting are powerful and that many of the difficulties encountered in the 1970's will be overcome in the 1980's.

Jan 1, 1985