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By A. E. Reisenauer, R. W. Nelson, G. W. Gee

A model assessment was made to evaluate contaminant transport to ground water from clay-lined and unlined tailings pits. The input hydrologic soil characteristics were measured on materials typical of those found at the Morton Ranch uranium mill site in central Wyoming. The assessment involved combined saturated and partially saturated flow and contaminant transport models for two-dimensional cross-sections typical of the proposed Morton Ranch burial pits. Specifically obtained from the models were contaminant flow paths, the advancing contaminant flow fronts for sorbed and non-sorbed constituents, and travel times of contaminants along flow paths. Such results enable evaluation of the environmental consequences for the alternative control methods.

Jan 1, 1980

By Steve Karl

"The International Tunnelling and Underground Space Association (ITA) held its 42nd General Assembly along with the 2016 World Tunnel Congress (WTC) April 22-28 in San Francisco, CA. The event was co-organized by the Underground Construction Association of SME (UCA). This was the first time the event has been held in the United States in 20 years.As cities demonstrate strong needs in tunnels and underground spaces for public transportation, subway stations, hydroelectric infrastructures and other underground infrastructure needs, the WTC 2016 provided the 2,319 attendees from around the world a unique occasion to discover the latest state-of-the art innovations in urban planning and underground construction projects in the United States and worldwide.The Congress, held in lieu of the UCA’s North American Tunneling Conference, included an exhibit that attracted 226 exhibitors in 298 booths. The exhibit had on display the latest in technical equipment and services from some of the largest and best companies in the international tunneling industry. The exhibit hall was also the place where participants were able to interact with the authors of the 168 posters and receive answers to various topics directly concerning civil engineers: innovative procurement processes, cost and risk management, contractual methods, BIM technologies and examples of innovative underground infrastructures built worldwide. And the technical program included 353 technical presentations – 185 podium and 168 posters.What is ITA?ITA-AITES is a nonprofit, nongovernmental organization that promotes greater use of underground space as a key instrument in sustainable development. Established in 1974 and based in Lausanne, Switzerland, ITA-AITES is made up thousands of professionals involved in the tunnel and underground space industry, including engineers, project owners, town planners, architects, industrial designers, companies specialized in public works and major structures, suppliers of construction site facilities and equipment, lawyers, politicians, researchers and academics, economists, financial experts and other stakeholders.ITA-AITES consists of 73 member nations and 300 affiliated members, including 15 major sponsors and 60 donors. The association is run by an executive council made up of 15 members elected by the 73 member nations, each representing a different dimension of the tunnel community."

Jun 1, 2016

By Andrew Torok

Activated bleaching clays, so called because of their ability to remove color bodies from bleach fats and oils, are produced from clays of bentonitic origin. Activation is achieved by subjecting these clays to physical or chemical alteration to increase selective sorption capacities (1) . The future of activated bleaching clays depends upon the ability of producers to recognize the new areas of applications which are arising, and their skill in developing sophisticated active clays to meet new and stringent requirements. The major portion of activated bentonites are produced for decolorization of oils. New techniques of activation will improve these clays for broader spectrum use. General properties expected to result from present activation methods are: 1. Modification of hydrophobic-hydrophilic properties and increased available surface area in non-aqueous systems, thereby improving sorption capacity and ability to remove color bodies from oils. The following additional properties will be expected from future activated clays: 2. High purity of the active clay with interfering impurities totally removed. 3. Increased selective sorption capacity in aqueous systems. 4. Selective chemical reactivity, such as oxidation or hydrolysis. This property is required for removing

Jan 1, 1971

By Eric Gilmore, Ron Tudor, Gregory E. Korbin, Bill McCormick, Brad Bush

INTRODUCTION Las Vegas has recently been termed the “Construction Capital of the Country”. It has also been acknowledged as the fastest growing city in the country for several years running. The rapid growth improves the economic picture of the region but it also imparts unusual demands on the area’s infrastructure. In 1994 the Southern Nevada Water Authority (SNWA)was working on a master plan to address the rapid growth. A long range analysis revealed the need for additional water treatment capacity and delivery systems. Short term projections showed that the current system would reach capacity in the summer of 1997 with the possibility of demand exceeding the supply. The River Mountains Tunnel #2 is part of a $150M scheme to quickly upgrade the system to meet the short term demand, improve the overall system operation and allow for a smooth transition into the larger additions being planned for the future. The SNWA selected Carollo/Black & Veatch (CBV) to provide detailed design and construction management for the upgrades. The River Mountains Contracts consisted of five separate contracts broken out separately to stream line a very aggressive (just 34 months) design and construction schedule. Necessary work included four miles of excavated and lined tunnel, connections from existing pipelines to and from the new tunnel including large diameter (to 3.66m(144 in)) valves, a 18 927cu m (5 million gal) regulating reservoir, a surge tank and a 170 343cu m (45 million gal) reservoir to add additional storage to the system. Notice to Proceed was given to Kajima Engineering and Construction (Kajima) on May22, 1995 for the construction of the River Mountains Tunnel #2. The design called for a tunnel to be driven 6070m (19 915ft) in rock and lined to a finished diameter of 3.71m (12.17ft).Excavation began on December 14, 1995 and holed through on April 30, 1996. Lining began on June 25, 1996 and a notice of Substantial Completion was issued on December 13,1996. This paper describes the measures taken to complete the tunnel in 18 months from Notice to Proceed to Substantial Completion. THE RIVER MOUNTAINS SITE The River Mountains are a low range of rugged mountains separating the Las Vegas Valley from its main supply of water, the Colorado River at Lake Mead. They are volcanic in origin and the harsh desert environment has left them as expanses of exposed bedrock rising 305m (1000ft) above the valley with little or no vegetation. An existing 3.05m (10ft)

Jan 1, 1997

By H. Ouellet, J. Paraszczak

The pneumatic jackleg drill remains a widely used tool in development and production drilling in many small-scale and narrow-vein underground mining operations in North America. Several drawbacks of this technology (unsatisfactory drilling rate, noise, vibration, presence of oil mist, etc.) and the successful introduction of water-powered jackleg drills in South Africa have stimulated the interest of many mine operators. The performance of both drill types have been tested in a mine site in Northwestern Quebec, Canada. Results of the testing of penetration and advance rates as well as environmental aspects are presented. They show a superiority of water-powered drills, even though the difference in performance is less significant than that reported from South Africa. Further research avenues are proposed to better evaluate the potential of water drilling technology in North American metal mines.

Jan 1, 1995

"A cationic surfactant, tetradecyl tributyl phosphonium chloride (TTPC), was first used as a collector. Flotation characteristics of muscovite using TTPC have been investigated through flotation tests. And dodecyl trimethyl ammonium chloride (DTAC) was tested for comparison. Their adsorption mechanisms on muscovite surface were clarified using zeta potential measurement, DFT calculation and molecular dynamics (MD). The flotation results indicate that the recovery of muscovite decreases when the pH increases in the presence of surfactants. When a maximum of recovery was reached, the dosage of TTPC was 2×10-5mol/L which was half of that of DTAC. Zeta potential measurements confirm that the TTPC displays a stronger collecting power than DTAC and is a superior collector for the muscovite flotation. DFT calculation and MD simulations show that TTPC interacts with the muscovite mainly through electrostatic attraction and hydrogen-bonding. The conclusions drawn from purely theoretical computations matched remarkably well with the experimental results. Keywords: Quaternary phosphonium salts; Flotation collectors; Flotation INTRODUCTION Muscovite mica is widespread in igneous, sedimentary and metamorphic rocks. It has the general composition KAl2(AlSi3O10)(OH)2. Muscovite mica exhibits perfect cleavage along the (001) plane, which exposes interlayer potassium ions[1-3]. In aqueous suspensions, the potassium ions readily enter into solution, leading to the development of a net negative charge on the (001) plane[4-6]. The surface of the muscovite mica is negatively charged at all pH > 1[7]. Due to the negative charge surface over the whole pH range of 2–12, the muscovite mica would not be expected to respond to anionic collectors in the absence of an activator. Conversely, the mineral is readily recovered using cationic collectors. However, until now, various amines and their derivatives (with N atoms as the center) are still the only available cationic collectors which still had their shortcomings such as weak selectivity, low flotation speed. Since few types of cationic collectors could be used, in some sense, the limitations of collectors are increasing significantly and the cationic flotation is facing more and more challenges. Quaternary phosphonium salts, as novel cationic surfactants, are widely used in antimicrobial, catalysis and surface modification field due to their biological activities, hydrogen bonding capability, stability and superior group electrical property[8-10]. There are a number of processes where quaternary phosphonium salt surfactants have shown better properties than quaternary ammonium salts and amines. Although the adsorption of quaternary phosphonium salt surfactants at the bacterium–liquid interface has been studied thoroughly, the case of adsorption in mineral surface has not been investigated thus far."

Jan 1, 2016

By G. Brien, O&apos

Selective in-plant breakage was investigated at a Central Queensland, Australia mine. Component seams and size fractions from in-plant samples were characterized petrographically and probability analysis of vitrinite reflectance data used to track the distribution of seam proportions through the plant. Results show that the 2 seams reported differentially to coarse and fine circuits, mainly as a function of coal type rather than rank. Seams were also preferentially concentrated in different size fractions of the coarse circuit. Breakage in the coarse coal centrifuge generated approximately 4% of -0.5 mm fines, but was not seam specific.

Jan 1, 1996

By J. Bartrum

Semi-autogenous, (SAG), milling operations can realize substantial Increases in mill throughput by removing and crushing critical size, slow grinding, material from the SAG mill. Full-scale plant testwork showed that modifying the Kidston SAG/ball circuit to a semi-autogenous-ball milling-crushing (SABC) circuit would increase plant throughput by 25 to 30%. The methods used to determine the value of the SABC circuit and the design of the circuit are discussed.

Jan 1, 1988

By Sergio Godoy P.

The Los Bronces porphyry copper deposit is located in the high Andes of Central Chile. Ore is mined from several tourmaline breccias and from an earlier porphyry. After years of experience in the geostatistical estimation of reserves in different zones of the ore body, we believe that success lies in considering the evaluation as an integrated process beginning with the analyses of the drilling density and sampling methodology, ending with the critically important reconciliation between the estimated and the actually extracted ore, in general, when errors or differences occur, focus is centered in the calculation stages of geostatistics. However, this paper demonstrates that all the evaluation stages are equally important and require the direct and continuous geologic input to ensure the best possible estimate within the frame of the geologic constraints.

Jan 1, 1992

By C. M. Jones

Cyprus Sierrita Corp. has developed a training program that has led to several significant improvements in safety performance and productivity. Truck productivity has increased 6% as measured by truck cycle times. Increased skill levels and awareness on the part of the mine's operators are due to the new training effort. Costs associated with productivity training have been about $185,300. This includes program development and execution costs, as well as lost productivity during the training itself. These costs are offset by $1.9 million in savings attributable to the increased skill levels of technicians due to the training effort. Cyprus Sierrita is a subsidiary of Cyprus Amax of Englewood, CO. The company operates a copper and molybdenum mining and processing facility south of Tucson, AZ, near the town of Green Valley. The Cyprus Sierrita operation produces about 109 kt/a (240 million lbs/ year) of copper, 11.3 kt/a (25 million lbs/year) of molybdenum, 31.1 t/a (1 million oz/year) of silver and 1.8 t/a (4,000 lbs/year) of rhenium. The opera¬tion employs 770 people at the site. About 200 of these employees work in the mine operations. Mining at Sierrita uses standard open-pit techniques. Crews of 43 people rotate on 12-hour shifts. Hourly technicians are nonunion and do not use rigid job classifications to define pay. Rather, the system is designed to pay employees for what they are able to do. Administering this effort requires that training opportunities are provided to those people who desire them. Successful training opportunities al¬low people to gain skills. The more skills an employee can demonstrate, the higher his or her "tech level." A technician's pay is commensurate with his or her tech level. Much of Sierrita's training in past years concentrated on building basic

Jan 1, 1998

By Carrie Smith

Along Michigan’s Upper Peninsula lies the Marquette Iron Range, home to iron mines. Just southeast of the region is the small town of Iron River, where Mary Korpi spent most of her chidhood and early adulthood. Though living in the heart of mining country, the industry did not pique her interest while growing up. As the daughter of two educators, she envisioned a different future for herself. Now, decades after working for one of the largest gold companies, she is gearing up for her term as the Society for Mining, Metallurgy & Exploration’s 2026 President.

Mar 1, 2026

By Robert J. Willard

In its search for additional ways to increase understanding of rock behavior, the Twin Cities Mining Research Center has turned to the scanning electron microscope, an instrument rapidly finding application in research concerned with surfaces of materials. Since features indicative of the manner in which rocks fail may be recorded on the surfaces of fragments as disintegration proceeds, this microscope might be used as a tool for seeking and mapping these minute features. In pursuit of such features, we chose to scan a portion of the fracture surface from a quartzite disk compressively loaded to failure between two pins centered along the disk's axis. The resultant fracture appeared as a rough, diametric plane, and the fracture surface near one of the loading points was scanned with the microscope.

Jan 1, 1969

By A. D. Hammond

"INTRODUCTION The recent drop in iron ore prices has claimed an unwitting casualty in vanadium. Vanadium is dominantly produced as a co-product of steel production. The recent shutdown at EVRAZ’s Mapochs steel-vanadium operations in South Africa has cut-off 10% of the world’s vanadium output. Earlier in February, 2015, Australia’s Atlantic Ltd. suspended operations at its Windimurra iron-vanadium complex after a fire caused severe damage at the plant. Since then, challenging market conditions has resulted in the permanent closure of this operation. This decoupling of vanadium production from integrated iron ore producers presents an opportunity for vanadium exploration companies to target single-product deposits. This trend is manifested in the increasing number of pure-play vanadium ventures around the world.The mine production of vanadium is dominated by three countries namely, China, South Africa and Russia, which collectively produce 98% of the world’s vanadium. While the use of vanadium as an alloy in the steel industry remains by far the largest application for this metal, growth in demand is expected to come from the renewable energy industry in the form of batteries for energy storage. This paper summarizes the current state of vanadium exploration, briefly describes the vanadium market and lists sources of future demand for the metal. TREND IN VANADIUM EXPLORATION The most active participants in the current vanadium exploration are pure-play vanadium ventures in Brazil, South Africa and Australia. These ventures are targeting deposits with higher vanadium grade than those typically mined in titaniferous magnetite operated by integrated steel-vanadium producers. The 10% shortfall in vanadium production resulting from the shutdown at EVRAZ’s Mapochs is expected to be partially compensated by Largo Resources’ Maracás Menchen vanadium operation located in the State of Bahia in Brazil, which commenced operation in August 2014 and is expected to reach design capacity of 11,400 tonnes of vanadium pentaoxide (V2O5) by the end of 2015. The estimated production1 for 2015 is 6,500 tonnes of V2O5 at a target production cost of $3.60/lb. This is the first vanadium operation to be placed in production in the Western Hemisphere in over 35 years."

Jan 1, 2016

By Ammar Henchiri

INTRODUCTION A current need of the phosphate industry is the development of process technology for treatment of high carbonate content ore. About 75 to 80 percent of the world phosphate reserves (1) are associated with carbonate gangue, which is not amenable to treatment by the existing techniques. Numerous laboratory and pilot plant studies have been devoted to carbonate-phosphate separation. Different techniques were involved (washing, sieving, attrition, flotation, calcination, and leaching). For technical and economical considerations, flotation appears to be an efficient process for this problem. Separation of carbonates (calcite and dolomite) from igneous phosphate is applied in industrial plants in Brazil, Finland, and South Africa. But, for sedimentary phosphate, no industrial realization exists at this time, with the possible exception of some plants in China. The main problems with sedimentary phosphates are: • high substitution by CO3-2 and F- for P04 -3 in the apatite lattice. • larger surface area of the phosphate particles because their surface is porous and irregular. • tendency of sedimentary minerals to produce more slimes in conditioning than the crystalline minerals, hence, larger dosages of collectors are required for sedimentary minerals. Investigations reported in the literature indicate that most processes developed for sedimentary carbonate-phosphate separation involved inverse flotation of carbonates using fatty acids as collectors (2), (3) associated with phosphoric acid (4), monosodium phosphate (5), F- (6), or SiF6 -2 (7) as phosphate depressants. Later investigations, conducted by A. Henchiri and G. Baudet (8), (9), (10), (11), (12), (13) in the BRGM technology department, of phosphoric esters revealed that these reagents are selective collectors for carbonate-phosphate separation. The above investigators developed a process which used phosphoric esters to collect carbonate minerals and sulfuric acid or sodium fluorosilicate as depressants for phosphate. Extensive comparative tests for different processes on the same phosphate sample show that the process developed at BRGM is one of the most promising methods proposed for sedimentary phosphate-carbonate separation. It should be pointed out, however, that phosphoric esters make abundant froths. The handling of these excessive froths will be a problem in an industrial-scale plant. This paper outlines test work performed in order to optimize and to improve the efficiency of the flotation process on a sedimentary phosphate ore selected from the Sra Ouertane orebody. The Sra Ouertane flotation process, illustrated on Figure 1, first removes carbonate minerals by inverse flotation and then recovers phosphate as a froth product, leaving quartz as a cell product.

Jan 1, 1993

By B. Dabrowski, J. D. Miller, D. Halbe, J. Hupka

An air-sparged hydrocyclone (ASH) mobile system was evaluated for continuous stripping and recovery of cyanide (the AVR process) from process water at a gold plant site. The ASH unit performed exceptionally well as an absorber. HCN was removed from the gas phase in a single one second pass with an efficiency exceeding 99%. HCN concentration in the discharged gas phase was lower than 10 ppm, which provided for a safe working environment. The stripping efficiency, controlled by the Henry’s Law constant, exceeded 40% in one pass.

Jan 1, 2004

When solid pillar is not left to separate different mining levels in underground mine with high dip angle deposit, waste rock in the backfilled stope could be a safety hazard to future mining activities on levels above or below the backfill. Different backfill methods can be used to eliminate this hazard according to the deposit shape and mining method. Building concrete pillar in ore drift of each mining level is one of them. Concrete pillar had been constructed in underground mines based on operational experience. Little design literature and pillar performance data can be found. At Great Basin Gold Hollister Mine, over two thousand feet of concrete pillar had been constructed. The project started with engineering design which combined civil engineering concrete design and the specialties of underground construction. Time Domain Reflectometry technique was installed to monitor the pillar movement and concrete cylinder samples were collected and tested for quality control. Engineering design, underground construction, quality control and concrete pillar monitoring, as well as precious concrete mixing data from years of experience are fully covered in this paper to give a general frame of concrete pillar method.

Jan 1, 2010

By L. Sletmoen, P. Rocque, E. DeSouza

Plans for achieving planned production rates at the Red Lake Mine High Grade Ore Zone required that the mine ventilation system be upgraded. Time constraints required that only a site assessment of the mine ventilation system be performed followed by recommendations for providing adequate ventilation conditions at the production zone. This paper describes the engineering assessment, design and commissioning of the ventilation system upgrade for achieving increased flows at the high grade ore zone. The work was successfully achieved with minimal capital expenditures and disruption to the mining cycle.

Jan 1, 2003

By R. Debkowski

Mining methods used to protect the workings in underground salt mines against the destructive activity of natural factors are presented in this paper. Major hazards and methods of elimination of their impact on the stability of workings, were determined. Old and modern technical means and technologies used for protection and preservation of the selected most interesting sites were characterized. The results of surveys and studies allowed proposing the change of mine structure i.e. dividing it into monumental and not-monumental part, which should improve execution of necessary protective works.

Jan 1, 2006

By Mark R. Stanton, Douglas B. Yager

Integration and synthesis of mine-site topography, geophysical, and geochemical data yields both two- dimensional and three-Amensional perspective models for the May Day mine located in the Cement Creek drainage near Silverton, Colorado. Induced polarization, geophysical data are spatially registered with geochemical data acquired from drill hole cuttings that are contoured m three-dimensional space, thereby permitting determination of the most metalliferous and sulfur rich zones of a waste pile. This spatial modeling application was developed to be a visually intuitive tool to aid in mine waste reclamation.

Jan 1, 2000

By J. G. Wargo

In situ leaching of disseminate gold deposits has been studied from a theoretical perspective to outline the operating environment for the process. Rock permeability and the relationship of permeability to the site of gold particle deposition are key factors in predicting the efficiency of in situ leaching. Permeability measurements, however, have rarely been made during gold exploration, so that secondary geologic features of the deposit must be used. This paper examines some of the geologic characteristics of disseminated gold deposits and comments on the problems and possibilities of in situ leaching of gold.

Jan 1, 1987