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By Joseph M. Driscoll

After 30 years of successfully mining gold, Newmont Gold has temporarily ceased production from the original Carlin Pit. In late 1993, the Carlin East decline was driven and an extensive underground exploration program was started. Today, Newmont Gold produces refractory ore from the Carlin East Underground at the rate of 864 t/d (950 stpd). Annual production is more than 3.1 t (100,000 02). More than 70 underground miners will be employed during Carlin East's estimated six-year mine life. About 70% of the ore at Carlin East is mined by mechanized longhole stoping with delayed, cemented backfill. The remaining ore is mined by underhand drift and cemented fill methods.

Jan 1, 1997

By Linda J. Dahl

The U.S. Department of the Interior, Bureau of Mines is developing a process to selectively extract manganese from oxide ores as part of its in situ leach mining research program. The Bureau is conducting site characterization studies of two manganiferous iron-formation deposits which include: drill core, regional stratigraphic relationships from the existing geologic database, ore body geometry, geologic structure, hydrologic conditions, proximity of ore minerals to the leach fluid paths, surface subsidence potential, and data collected from laboratory leaching experiments. This information is being used to evaluate the technical, environmental, and economic feasibility of in situ leach mining of manganese for these two deposits. This paper will focus on the stratigraphy, mineralogy, ore textures, fractures, permeability, and porosity as they relate to in situ leach mining.

Jan 1, 1992

By Howard M. Wells

Portfolio theory and the Capital Asset Pricing Model (Modigliani and Pogue, 1974) provides an investment decision rationale which takes account of the benefits of diversification in reducing effective risk, but this theory does not consider the financial capability of the firm to survive large losses if they should occur. The LL-curve theory (Wells, 1976) takes the latter consideration into account, but it does not provide for the effects of diversification. This paper pro- poses a general theory to account for both diversification and the financial capacity of the firm to underwrite the investment risks.

Jan 1, 1983

The role of ZnSO4 in activation of sphalerite (ZnS) and deactivation of lead-activated sphalerite has been investigated. Adsorption of metallic ions at the solid-solution interface, electrokinetic results for sphalerite under different chemical conditions, and thermodynamic calculations were used to elucidate the mechanisms involved. It is shown that flotation response of sphalerite in absence of activators is rather weak and that adsorption of ethyl xanthate on the mineral mainly electrostatic in nature. Zinc sulfate is found to activate the mineral but only in a narrow acidic pH range. This is attributed to the increase of zeta potential as well as the possible increase in amount of negatively charged bulk precipitated zinc xanthate. Lead ions activate sphalerite in a wide pH range and the lead activated mineral assumes a flotation behavior similar to that of galena (PbS). However, addition of ZnSO4 depresses the lead-activated sphalerite by replacing lead ions at the mineral/solution interface.

Jan 1, 1999

By J. Kemeny, K. M. Kim

A site-specific blasting model has been developed for the Asarco Mission mine. The main inputs to the model are the in situ block size (F80), the post-blast fragmentation (P80) and the intact tensile strength (To). The output from the model is the specific blast energy (ESE). Modern techniques are being used to obtain the input parameters for the site-specific blast fragmentation model. In particular, image processing software is used to obtain both the in situ block size and the post-blast fragmentation, and the Schmidt hammer is used to obtain the tensile strength at numerous locations throughout the rock mass. An initial model was developed using five test shots in an area of the mine that contains argillite and is relatively homogeneous. This process also included calibrating Schmidt hammer readings against actual Brazilian tensile measurements. The model for argillite will be updated as more tests are conducted, and the model will be extended to the four other primary rock types at the Asarco Mission mine.

Jan 1, 2011

By X. P. Zheng

Barium fluorphlogopites were synthesized in the laboratory in order to investigate the effects of composition and crystal parameters on surface properties and floatability. The negative surface charge of mica is determined by the barium content, the crystal cell volume, the distance between layer structure and the Ba-O bond length. The higher barium content, the larger the cell volume and distance between the layer structure and the longer the Ba-O bond, the more negatively charged the surface is and hence the more easily adsorbed to cationic collectors. When an anionic collector (sodium oleate) is used, barium oleate forms on the mica surface and hence chemical adsorption occurs.

Jan 1, 1993

By K. V. Godfrey

With the increasing need to exercise better control over mill circuits has come a requirement to develop rapid, accurate means of measuring circuit parameters. One of the most important parameters is the assay of the material in the circuit (or about to be introduced to the circuit). To date, most on-stream analysis has been performed using X-ray fluorescence equipment. Neutron activation offers an alternative method in certain circumstances, and one which has several interesting advantages. Recognizing the need for a simple, safe neutron activation unit suitable for on-stream analysis in the mineral industries, Atomic Energy of Canada Limited has designed, built and tested the SHERLOCK system. One prototype (SHERLOCK I) is located in Ottawa and is now used primarily in research. A second prototype (SHERLOCK III) is located in Vancouver at the laboratories of B.C. Research. This unit is being used for some development research and for evaluating the unit in specific applications. Most of the work completed to date has been aimed at proving the technique and in developing some of the parameters needed to design systems for a milling plant. Funding for the work has been through research grants and through sponsor¬ship by interested companies.

Jan 1, 1971

"In addition to outstanding technical sessions and networking opportunities, the SME Annual Conference and Expo offers attendees a chance to see the latest and greatest technology that the industry has to offer. The 2017 SME Annual Conference and Expo was no exception as 575 companies filled 756 booths from Feb. 19-22 in Denver, CO. The following is a look at some of the vendors that were on hand.AIL MiningThe Edge, featured by AIL Mining at the 2017 SME exhibit, is a four-flange structural liner designed to be an alternative to structural plate’s traditional lapped seams and to help mine operators build more efficiently and safely. It is ideal for creating underground structures, such as mine shafts, ventilation raises and escape ways. The Edge is available on SuperCor structural steel plate — 10 times stiffer and five times stronger than traditional steel liner plate. It facilitates curved structures, both horizontal and vertical, and eliminates the need for ring beams. It is ideal for remote sites. For added safety, structures can be assembled from the inside, and the leak-resistant structures can be dismantled and removed easily. Brackets can be attached to mine shafts or vent raises to support Alimak rails or climbers. Similarly, brackets or hangers can be attached to drifts or tunnels to support mine air, water or electrical utility services.ArcadisMining companies spent nearly $12 billion on water infrastructure worldwide in 2014, reflecting the industry’s heightened concern about environmental issues and social, regulatory and political risks.So, with an increasing focus on water reuse and recycling, mining companies must have effective water management plans that include sustainable solutions. Also, many water quality issues fall under both state and federal regulatory jurisdictions. To solve these problems, Arcadis provides comprehensive ground- and surfacewater technical support in a complex hydrogeologic setting. It can characterize the nature and extent of mine-related constituents in ground water and surface water, as well as the complex interactions between the two waters, and prepare the operational permits needed by mine and tailings facilities. As an example, Arcadis constructed a hydrogeologic and geochemical conceptual site model that improved site understanding for a molybdenum mine in the western United States that spanned several watersheds. It also provided technical support for permitting and compliance issues, allowing the mine to return to active production."

Jan 5, 2017

By H. D. Lelono, M. Walden, G. Johnson

3D modelling can be used throughout the mine lifecycle and has proven to be a powerful tool for consultants and mining companies. One of the most significant benefits of 3D models is their ability to enhance collaboration, communication, and understanding between the mine owner, design engineers, and other relevant stakeholders that have a shared interest in responsible mining and site management. Tailings and mine waste management is an interdisciplinary effort that requires effective coordination and communication between a wide range of consultants, operators, and stakeholders alike. The increased emphasis on Environmental, Social, and Corporate Governance (ESG) highlights the importance for mine operators to engage and communicate with all parties involved in the planning, permitting, operation, and closure of mine sites. 3D models are valuable tools that can be used for development of geotechnical conceptual models, allowing for improved design and monitoring of Tailings Storage Facilities (TSFs). A clear conceptual understanding of a TSFs subsurface geology and foundation characterization is essential for proper tailings management, design, and planning. Visualization with 3D modelling can simplify the interpretation of the, oftentimes intricate, mine sight subsurface settings and allows for quick and effective geotechnical conceptualization. 3D models can be used to identify data gaps, optimize field investigations, and streamline the development of numerical stability or groundwater models. They can help communicate the complex nature of subsurface and TSF interactions in a clear, concise, and accurate manner to both technical and nontechnical stakeholders. This paper discusses some of the benefits of 3D modelling in relation to geotechnical analysis for tailings management and provides methodologies for how to improve upon some methodologies that are considered industry standards.

Feb 1, 2023

By M. Westerstrand

It is known that the water chemistry of the process water during ore refinement can affect product quality, such as iron pellet strength. The main objective of this study was to quantify the amounts of major elements, such as Ca, Mg, Na, S and Cl carried by process water and by magnetite grain surfaces to the end product, iron ore pellets made from magnetite ore from the Kiirunavaara Mine in northern Sweden. In addition, the amount of colloids (0.22µm ? 1kD) in the process water was examined by ultrafiltration. The amounts of various elements sorbed to the magnetite surfaces were estimated by leaching with Milli-Q water, MgCl2, NH4-acetate and Na-acetate. Total dissolved solids were between 1,446 and 1,775 mg/l, dominated by Ca, S, Na and Cl (89%). The colloidal fraction was less than 3% for major ions. For Ca and Mg, sorption to magnetite surfaces was a much more important transport mechanism for the pelletizing process than evaporated process water, but for Na, Cl and S process water was an important carrier.

Jan 1, 2010

By L. J. E. Hofer, L. F. Zeiler, D. A. Giardino

The Jones Trickett Ratio (JTR) is generally used in investigations of fires and explosions for the determination of the composition of the fuel. This paper takes a close look at the JTR and finds it unreliable and ambiguous for the determination of fuel composition. A new index is presented, termed the (H/C) Index which uniquely determines the fuel composition. The (H/C) Index is simple to use requiring only the results of a single gas analysis of the combustion products. Experimental data testing the (H/C) Index for methane, propane, ethylene and coal dust are given, showing that the Index unambiguously determines the composition of the fuel. The (H/C) Index is also applied to the gas analysis data of several mine fires, illustrating how the Index changes with the progression of the mine fire.

Jan 1, 1993

By E. J. Mayhew

Bentonite and newly discovered deposits of sepiolite, saponite, and hectorite are now being processed and marketed from the Amargosa Valley of Nevada. All of these deposits are large. The bentonite has been known for decades and is the whitest known. The only other sepiolite deposit is in Spain. The only other commercial hectorite deposit is at Hector, California. No other saponite deposit is known. All the components except bentonite are hydrous magnesium silicates. The bentonite is mixed layer Na-Ca. All the materials have characteristics unique to their locale and type, such as high yield point for drilling muds and liquid suspending agents. The sepiolite has geothermal stability. Figure 1.

Jan 1, 1979

By Ali Kazmi, Wern-ping N. Chen

A load rating procedure was performed to evaluate safe load capacity of the Port of Miami Tunnel (POMT), FDOT Tunnel No. 871071 SR 887. The rating procedure performed on a total of eleven stations beneath roadways and with fill depth less than the tunnel exterior diameter (42 ft). Calculations on tunnel sections passing beneath roadways were performed to evaluate the structural response of the sections subject to moving vehicular loads, dead load, and earth pressures. Ratings were performed in accordance with AASHTO and FDOT guidelines. The procedure considered two types of vehicles (HL-93 and FL-120) and two rating levels (Design level and Permit level). As part of HL-93 vehicle, Tandem load was also considered for rating, separately. For HL-93 and HL-93 Tandem, inventory and operating level ratings were performed. The results show rating factors are high. The minimum rating factor is 16.8 using Inventory truck HL-93. For Permit level using FDOT FL-120 truck the minimum rating factor is 6.9. As can be seen, rating factors are higher than comparable analysis for bridges. This paper explains how the procedure can be implemented for tunnels and evaluates the rating results.

Dec 1, 2022

Software exhibitors at MINExpo will feature the newest, the best, the most comprehensive computer-based tools available to get minerals from the ground to the market. From the ?cloud? to the pit, the variety that will be featured is almost limitless ? a digital tool for every phase of the mining lifecycle. Blue Sky Network SkyRouter brings the Blue Sky Network to the cloud. Using its interactive Web portal, SkyRouter, with detailed mapping and integration with Google Earth, the Blue Sky Network links enterprises to personnel and assets anywhere on earth through Iridium satellites. The cloud-based solution is designed to support connectivity with remotely dispersed mobile assets, including Blue Sky?s dual-mode GSM and Iridium tracking and communications services. This enables seamless connectivity with assets in problematic cellular reception areas, where only 10 percent of the Earth is covered, and in remote locations.

Jan 1, 2012

By William X. Chavez

The Mantos Blancos copper-silver district is located in northern Chile about 45 kilometers northeast of Antofagasta, as shown in Figure 1. Disseminated and veinlet copper and copper-iron sulfides containing economically significant silver values are hosted by andesitic to rhyolitic volcanic rocks of probable Jurassic age (Chavez, 1983). Field, mineralogical, textural and lithochemical evidence show that three major alteration types may be recognized within the district: (1) district-wide sodium metasomatism, manifested as albitization of feldspars and development of albite veinlets and pore-fillings, (2) local to widespread, incipient to intense addition (chloritization) or removal (bleaching) of magnesium and iron and (3) local to widespread, moderate to intense hematitization, usually spatially associated with bornite-digenite-covellite (as specularite) or digenite-covellite-chalcocite (as red hematite staining with or without specularite) mineralization. Carbonatization, occurring as veins, veinlets, vesicle fillings and irregular patches of calcite, varies in magnitude of development but is widespread. Sericitization of feldspars and groundmass is only locally intense yet is generally present as incipient alteration throughout the district. The district-wide albitization of the Mantos Blancos volcanic sequence has altered what were originally more potassic and calcic, less sodic, rocks to what are now more properly referred to as keratophyres (Battey, 1955; Gilluly, 1935, Hughes, 1975). The petrographic and lithochemical characteristics of the three major alteration types noted above are summarized below.

Jan 1, 1984

By Brian Ulrich

The majority of individuals involved in the mining industry can appreciate and under-stand that mining is an activity that is necessary to satisfy the very basic needs of society, and to assist in accommodating our ever-changing world. As the expression goes, ?if it can?t be grown, it has to be mined.? And at this point in time, society has granted the mining industry the right to go about the business of mining, with the general anticipation that the work will be carried out without causing undue harm to the environment or populations in and around the mining operation. The term ?sustainable development? is gaining momentum as a popular concept, and indeed it has become something of a catch-all phrase, but it is important that the idea behind the term is not cast aside as a nonsense buzz word, as it simply is an indication that development (e.g. mining) can be satisfactorily carried out with an eye toward stewardship of the environment and society. On Feb. 19, 2010, a round-table discussion (Roundtable 2010) on ?Strides Toward Sustainability in Mining? was hosted by Knight Piésold and Co. (Knight Piésold) at the Red Lion Inn and Casino in Elko, NV. Knight Piésold had local representatives (Bryan Ulrich and Steve Boyce), as well as representatives from other office locations (Cynthia Parnow and Rick Damiani from Denver, CO, and Rick Frechette from Tucson, AZ) to help facilitate the discussion. The meeting played host to 30 attendees from five states. Attendees included personnel from nine mining properties and various corporate offices. The majority of participants were people who are directly involved with environmental work on a day-to-day basis. Others were project managers whose jobs involve some level of environmental focus.

Jan 1, 2010

By Kathleen Lagnese, Srikanth Muddasani, Kashi Banerjee, Carla Robinson

"Mine water generated from underground coal mining operations contains both dissolved and particulate solids. Dissolved solids primarily consist of sodium, calcium, magnesium, potassium, chlorides and sulfates. When discharged to a receiving stream without treatment, these constituents create a potentially toxic environment for aquatic life.A case study is presented to discuss how a centralized treatment plant treats mine water from six locations to meet discharge limitations for chlorides. Located in West Virginia, this facility consistently achieves less than the National Pollutant Discharge Elemenation System (NPDES) permit limitation of 218 mg/L chlorides in the discharge while generating almost zero liquid waste. The dissolved solids concentration in the influent ranges between 5,000 and 10,000 mg/L, with chloride concentrations of 1,000 to 2,000 mg/L and sulfate concentrations of 2,000 to 6,000 mg/L.The mine water is treated using advanced treatment technology to produce clean water for discharge or reuse. The treatment process comprises aeration, softening, filtration, reverse osmosis (RO) reject softening, evaporation, crystallization, final effluent remineralization and sludge dewatering. The solid waste generated in the treatment process is landfilled on site. The leachate is sent back to the facility’s thermal treatment process. Because no liquid waste leaves the property, this plant is termed a zero liquid waste (ZLW) facility.The advanced water treatment system was built to meet a new 218 mg/L regulatory limitation imposed by the West Virginia Department of Environmental Protection for chlorides discharged to surface waters. The system is designed to treat a maximum flow of approximately 795 m3/h (5 million gpd) of mine water. The treatment process utilizes RO membrane treatment to achieve the effluent criteria, and evaporation and crystallization technology to manage the RO concentrate from the water treatment process. As a result, the system produces clean water for discharge while generating zero liquid waste. The effluent water can be used for industrial purposes or discharged to a receiving stream. A water impact index (WIIx) study indicated that discharge of this high-quality water into the Monongahela River watershed may improve the water quality for downstream water users. The waste produced in the treatment process, including softening sludge and salt, is disposed of in an onsite landfill. Currently, the plant is treating at an average flow of 490 m3/h (3.1 million gpd) of mine water with an average influent chloride concentration of 1,530 mg/L and an average effluent chloride concentration of 11 mg/L."

Jan 1, 2014

By James J. Gusek

The Atlantic City iron mine is located in Fremont County in central Wyoming, near the historic gold mining camps of Atlantic City and South Pass City. The mine lies on the southeast flank of the Wind River Mountains at an elevation of about 2,470 m (8,100 ft) above sea level (Fig. 1). An 81-h M2 (200-acre) tailings impoundment at the Atlantic City taconite operation has been a source of blowing dust. The site qualified for reclamation under Wyoming&apos;s Abandoned Mine Land (AML) reclamation program. The ultimate reclamation construction incorporated commercially available organic amendments and fertilizers into a 300-mm- (12-in.-) thick cap of a sterile clay loam cover material. The water level was lowered in an adjacent flooded mine pit that was feeding uncontrolled seeps into the tailings basin. A wide tailings pond spillway was built that allows flood control while minimizing seasonal water-level fluctuations in the pond. Rock berms and rock snow fences were built for wind-erosion control and soil-moisture preservation. Future work includes tree planting in the protective wind/ snow shadows of rock berms and rock snow fences and plugging a decant pipe. US Steel opened the Atlantic City iron mine in August 1962. It closed in 1983. Taconite iron ore was mined by surface methods. The ore was magnetically separated from the waste. The magnetic concentrate was mixed with bentonite, formed into pellets and roasted to produce a blast furnace feed stock for US Steel&apos;s blast furnaces in Geneva, UT. The pellets were hauled by rail to the Geneva Iron Works. The Atlantic City Mine produced three types of wastes. These included waste rock overburden from mining, a coarse-grained (sand to small-gravel sized), nonmagnetic reject rock termed "cobbs" and fine-grained tailings ranging from 600 to 75 µm (28 to <200 mesh). The waste rock has been used as an aggregate/rip rap source by a local contractor and the Wyoming Department of Transportation (WYDOT). WYDOT also

Jan 1, 1998

By Fred Pena

Cyprus Pima Mining Company is located in the Mineral Hill District of southern Arizona, approximately 22 miles south-southeast of Tucson. Cyprus Pima Mining Company is owned 50.01% by Cyprus Mines Corporation, 24.99% by Utah International Incorporated, and 25% by Union Oil Company of California, with Cyprus having the management responsibility. Cyprus Pima&apos;s history has been one of continued expansion from an initial plant of 3,000 TPD in 1957; 6,000 TPD in 1963; 18,000 TPD in 1966; 36,000 TPD in 1967; and 53,500 TPD in 1972. The major reason for Expansion IV was that a large volume of low-grade ore had to be moved to get at a higher grade ore in the course of proper pit development. With mining costs already defrayed, this relatively hard, low-grade material became economically profitable for subsequent milling and concentrating treatment. Similar material previously stockpiled was available for ore treatment. In an effort to meet the continuing search for lower unit costs, the largest milling and concentrating equipment had to be examined. The management of Cyprus Pima Mining Company began investigating autogenous, and semi-autogenous milling in 1964 when two carloads of ore selected from the Cyprus Pima pit were sent to the Koppers--Hardinge Operation at York, Pennsylvania for testing. One car contained approximately 40 tons of hard arkosite and the other contained approximately 40 tons of ore classified as soft Hornfels. The purpose of the testing was to determine the amenability of both ore types to autogenous or semi-autogenous grinding.

Jan 1, 1974

By C. Sampaio, C. Petter, M. Veras

"INTRODUCTION Use of sensor technology applied to the gravimetric beneficiation is intended for the selective preconcentration or separation of various minerals. Sensor Based Sorting (SBS) uses sensors to identify the particles and separate them by a mechanical process (flap) or pneumatic ejection valves (Wotruba et al. 2014). The principle of the SBS technology to separate mineral particles consists of three phases which cover feed,detection and separation. (killmann, 2009 Apud nienhaus et al. 2014). The applicability of the technique in an early stage of beneficiation enables free particles and poor grade to be a part of the process. The mass of tailings to be processed can be removed at the initial stage to save energy, water and equipment maintenance (Wotruba et al. 2014). Lindner (2010) suggested that the use of SBS technology would only will be possible if there exsists an electromagnetic interaction in all the wave spectra interacting with the solid ore. The interaction of electromagnetic waves depends directly on the characteristics of the material. The material receives a spectrum of electromagnetic waves by irradiation and this results in a reduced wavelength with differing types radiation such as fluorescence, reflection, remission, absorption, transmission and transmission. The frequency of the wave spectrum varies between 1000 and 1020Hz, illustrated by the data in Figure 1, which shows that each type of sensor emits a wavelength inversely proportional to the frequency ranging from 10-11pm to 104km, and the frequency that varies between EHz 103 and 1020kHz. The difference between the electromagnetic spectrum variations can only be visible to the human eye at wavelengths with intervals between 380nm and 780nm (Wotruba et al. 2014). One of the main advantages of operating with imaging sensors is the versatility of the images which can take on zero, one, two or three dimensions shown below as a point, a line, an area or a spatial image, as illustrated in Figure 2. According to Schubert (1988), to separate a mineral particle it is necessary to follow the characteristics of mineralogy, physics and chemistry with or without use of water. The use of new technologies can help reduce operating costs and improve utilization of mineral resources."

Jan 1, 2016