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By A. Kaina

The San Luis deposit is one of the few documented gold deposits on a detachment surface. This paper presents mineralogic and geochemical data that was gathered to characterize the mineralization, classify the ore deposit, and provide details of the ore forming process. Included are data on the paragenesis; alteration-mineral assemblages major and trace element geochemistry, and fluid inclusions. The San Luis deposit occurs on the western slope of the Sangre de Cristo Mountains adjacent to the San Luis Basin about 5 miles northeast of the town of San Luis in Costillo County, south-central Colorado. Mineralization was discovered in the district in the early 17th century. Production began in 1890 on lead-silver ores from which the district took the name the old name of "El Plomo". From 1897 through 1934 gold was intermittently produced. Battle Mountain Gold Company took an option on the property in 1987 and proved on ore body comprising an eastern block that has 1,277,300 t ore at a grade of 1.68 g/t and a western block of 9,744,000 t with a grade of 1.34 g/t. Production began in 1990. A companion paper by Benson (1994) describes the San Luis district and the ore body, hence the reader is referred to this or Robert and David (1990) for details of the geology from which the following is summarized.

Jan 1, 1994

By A. L. Coello Velázquez

The subject of this paper is particle population balance models (PBM) that describe mineral impact crushing behavior; it is mainly concerned with the selection and fragmentation distribution function due to their importance in this context. The data obtained by Datta (1999) by applying impact pendulum testing to single limestone particles, used by Austin (2002, 2004a and 2004b) to obtain the principal parity of fragmentation functions, were processed in order to compare them with the results of other authors, such as Nikolov (2002 and 2004) and Vogel and Peukert (2003 and 2005) so as to increase knowledge of impact crushing. From this data it has been possible to obtain the performance models of the principal parameters of fragmentation function, thereby reducing the number of experiments necessary to model the impact crushing process. The authors also propose a simplification of the selection function model posited by Austin (2002).

Jan 1, 2011

By M. J. Friedel

The U.S. Bureau of Mines (USBM) investigated the use of seismic refraction tomography (SRT) for identifying changes in pillar loading at the Foidel Creek coal mine near Steamboat Springs, CO. The inherent three-dimensional problem of directly imaging coal pillar conditions is reduced to a single plane by considering only the load transmitted from the pillar to the adjacent floor rock. Floor strata velocity tomograms (at two pillar locations) illustrate that loading conditions are non-uniform and non-unique. Also, time sequence monitoring, as the longwall face advanced, demonstrated that SRT can be used to image spatial changes in loading conditions. SRT offers the mining engineer a simple and flexible technique for evaluating pillar conditions, and thus, both present and alternative mine designs.

Jan 1, 1994

By C. M. Brinckerhoff

Much has been written in the mining technical magazines about the caving system. Many of these articles were published in the Transactions of the American Institute of Mining Engineers prior to World War II. In recent years little has been written on mining methods or on the detailed planning always required. Block caving had primarily been used to mine deep copper ores in Africa, the United States and in Chile, although other ores had been mined by this same system. Asbestos ore had been caved in Canada, tin ore in Bolivia, molybdenum ore in Colorado, iron ore in Wyoming and Sweden, and limestone in California.

Jan 1, 1984

By D. Spitty

Mining companies often have many disparate systems and repositories of data in their organization for planning and scheduling outbound mining supply chains. To optimize ore quality, throughput, transport logistics scheduling and delivery to contract, planning teams need to model and manage the value chain accurately and achieve a consolidated, enterprise view of operational performance. Planning teams coordinate a complex series of activities to ensure production forecast accuracy. They also negotiate and execute complex contracts often with disconnected and limited visibility of production forecasts, quality, and variability with little ability to accurately market potential product specifications over longer time horizons. This market is becoming increasingly dynamic, with increasing variability and the time for planning teams to react is decreasing. This is driving the need towards using science to generate the necessary scenarios required to support the decisions made by planners on a frequent basis. Resource-to-Market is a highly flexible, user-configurable supply chain management system for the mining and metal processing industries. This provides an integrated view of the supply chain that supports the dynamic nature of planning in a mining company, embraces variability of elements across the supply chain with the ability to optimize across all the functional areas of the operation to enable optimal decision making for often competing objectives such as throughput, quality, cost, revenue and profit.

Feb 23, 2014

By Dan Ifrim, Andre Solecki

Tunneling could be a major challenge to tunneling contractors as tunneling operations can be seriously affected by the Tunnel Boring Machine (TBM) performance. Specifying the appropriate TBM methodology, selection of systems and features, is critical for managing tunnel risks and contribute to successful tunneling project. The paper analyzes tunneling records from the recently completed City of Toronto’s Ashbridges Bay Treatment Outfall tunnel project and underlines the righteous selection of the TBM type and associated TBM systems in achieving good advance rates during tunnelling and managing project risks. The paper intends to draw attention of a few aspects of TBM technical specification importance and highlight the lessons learned from this process.

Jun 13, 2023

"The 35th Annual American Mining Hall of Fame Awards Banquet and Fundraiser, sponsored by the Mining Foundation of the Southwest (MFSW), will be held at the JW Marriott Tucson Starr Pass Resort & Spa on Saturday, Dec. 2, 2017. This year, the Foundation will honor one living Hall of Fame inductee, two Medal of Merit recipients, four honorees from Mining’s Past and an Industry Partner for their respective contributions to the mining industry.Gary J. Goldberg will be the 2017 Hall of Fame Inductee and will serve as the keynote speaker at the awards banquet. Goldberg was appointed president and chief executive officer and joined the board of directors of Newmont Mining Corp. in March 2013. Prior to this appointment, he served numerous companies in key positions including Rio Tinto Minerals, US Borax and Coal & Allied Industries. At every appointment, he was able to improve safety concerns and reduce injury rates. While serving as chairman of the National Mining Association, Goldberg launched the CORESafety initiative and US Borax was the first mining company to receive the California Governor’s Environmental and Economic Award.The Medal of Merit will be awarded to John C. Lacy, a shareholder of DeConcini McDonald Yetwin & Lacy, P.C. and a director of the Global Law Center at the University of Arizona’s Law School. Lacy’s law practice concentrates on mining and public land law and encompasses transactional and title consideration involving acquisition of mineral rights. He played a crucial role in the revisions to the mining law of the Republic of Bolivia and the English translation of the mining laws and regulations of Mexico. Lacy’s expertise in mining law impelled the University of Arizona James E. Rogers College of Law to approach him to head the new Global Mining Law Center in 2015. The program now partners with the Lowell Institute for Mineral Resources and offers cross-listing of courses"

Jan 10, 2017

By E. C. Westman, F. J. Shreve

This paper presents the design and construction of a multi-channel geophone array that improves tomographic imaging capabilities in both surface and underground mines. Especially important in the design of the array is sensor placement. Three issues related to sensor placement are addressed in this paper: 1) sensor placement in long, horizontal boreholes, 2) development of simple, robust, MSHA-acceptable clamping unit, and 3) orientation of the geophones within the borehole. Improved imaging capabilities will produce energy, environmental, and economic benefits by increasing exploration accuracy and reducing operating costs.

Jan 1, 2002

By S. R. Dismukes

Mining is likely to be targeted by The United States Environmental Protection Agency (“EPA”) as one of its key enforcement targets for fiscal year 2002-2003. Identifying the mining industry as an enforcement target, coupled with an increase in enforcement activity in recent years, places each mining operation at increased risk of receiving enforcement attention. A properly developed and implemented Environmental Management System (“EMS”) tailored for your operation is invaluable in reducing the risk of incurring liability for non-compliance. At the heart of an effective EMS is an audit program that checks the company’s compliance with environmental requirements. In addition, audit privilege (in select states), voluntary self-disclosure, and the attorney-client privilege serve as very effective tools for managing those liabilities that may arise during auditing a well-developed program. Of course, these latter tools are effective only if the auditing program is properly structured and properly managed. EPA and some states also provide varying degrees of immunity for environmental violations that are voluntarily disclosed in writing by the company. However, self-disclosure laws and policies typically prescribe stringent requirements for parties seeking to take advantage of them. For example: U.S. EPA has recently extended the time period in which to provide full written self-disclosure to 21 days. However, U.S. EPA’s revised Self-Disclosure guidance also addresses when a company obtains knowledge of a violation for purposes of triggering the 21-day clock and specifically extends the knowledge requirement to include the company’s agents and consultants. This expansion increases the difficulty companies may have in clearly defining and managing when they obtained knowledge. This difficulty increases the importance of managing factual development and the strategic use of other

Jan 1, 2001

Introduction The US mineral industry in 1983 participated in the recovery from the recent recession. Compared with 1982, the value of raw nonfuel mineral output rose 8% to $21.2 billion. The $218 billion worth of goods processed from this crude mineral output represented a 9% increase over 1982. Even in real terms, these figures reflect growth. Demand for nonfuel mineral materials, of course, depends on the overall state of the economy, which steadily improved each quarter in 1983. Of particular importance to the mineral industry were surges in key mineral-consuming sectors such as construction and automobile manufacturing. New housing starts rose one-third, to 1.7 million units, while automakers turned out about 35% more cars (6.8 million) and 25% more trucks (2.4 million) than in 1982. These are significant increases, even considering recent trends toward smaller, lighter vehicles, and multiple-unit housing. A comeback for the mineral industry, however, is bound to proceed unevenly, particularly at the beginning. Traditionally, the industry lags behind the rest of the economy during a recovery, and some mineral products respond to overall economic improvement more quickly than others. This pattern has been repeated many times and the industry is used to it. Mineral executives know it is best to be patient and cautious during the first stages of an economic upturn. Many experts say that it may take extraordinary toughness, patience, and caution this time around. Steel Improves Raw steel production - a major indicator of both material use and mineral production - rose 14% to 77 Mt (85 million st), stimulating a 7% rise in domestic iron ore production to 39 Mt (38 million It). Still, the iron ore industry operated at less than half capacity, with most major mines remaining closed for part of the year. Iron ore imports dropped 24% to 10 Mt (11 million st), so demand was partly met by withdrawals from stocks. Despite the increase in steel production for 1983, output remained far below levels of just a few years ago. For example, 1983 production was still 29% less than in 1981. Raw steelmaking capacity actually declined about 10% during the year to 122 Mt (135 million st). The industry continued to cite steel imports, especially those from developing nations, as a major cause of domestic capacity loss. As long as steel production remains weak, steelmaking metals suffer. Domestic producers of bulk ferroalloys of chromium, manganese, and silicon operated at about one-third capacity in 1983, with six of the 19 companies involved being closed all year. The US mined no manganese or chromium, and very little nickel, although the country's only nickel mine did resume production in November. Molybdenum production, at 13.6 t (15 st), was only about one-third as much as in 1982. The major molybdenum mines, Climax and Henderson in Colorado, remained closed all year. To meet demand, molybdenum stocks were halved to 19 t (21 st). Mine shipments of tungsten, another mineral tied to steel production, dropped 30% to 1.1 kt (1,200 st) of contained metal. One of the most positive responses to the general economic recovery came from the aluminum smelting industry. By the end of the year, it was operating at about 79% capacity, compared to 59% in January. Nevertheless, the 3.3 Mt (3.64 million st) of primary aluminum produced represented only a slight increase over 1982. Total bauxite imports were about 27% below 1982 levels. Production of magnesium metal rose 11% to 100 kt (110,000 st). But titanium was more typical of other

Jan 5, 1984

By George H. K. Schenck

The North American-based mining engineer needs to understand the differences that exist between mechanical mining or boring machines built on this continent and those built in Europe. The differences Ere most clearly seen when machines for large-sized openings--about 15 feet high-are considered. This report will focus on the innovations of European origin. The rock-breaking tool, drag bit, or roller cone that is efficient for a particular project is related directly to the strength of the rock involved. This strength is generally stated in reference to the rock's unconfined compressivee strength in pounds per square inch (psi) although it is well recognized that a rock's shear strength is also important. Compressive strength has been adopted because it is simple to test for and provides a convenient comparison. Table 1 relates cutter type to compressive strength and indicates the general nature of the machine innovation devel¬oped in Europe.

Jan 1, 1970

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Red mud has been reported as a potential resource for lithium. To investigate the leaching behavior of lithium, a lithium-rich red mud was neutralized with hydrochloric or oxalic acid and then leached with acetic acid. When red mud was neutralized using dilute hydrochloric acid, about 58 to 60 percent of lithium was leached with 25 percent acetic acid at 95 °C for 60 min, while more than 95 percent of sodium and 85 percent of calcium were dissolved in the leachate solution. When oxalic acid was used to neutralize red mud prior to acetic acid leaching, lower lithium leaching efficiencies of about 42 to 47 percent were observed. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the same conditions. In this study, 25 percent (v/v) of acetic acid at 85 °C for 60 min was demonstrated to be the optimum conditions for lithium extraction from oxalic acid-neutralized red mud using acetic acid. The results are useful and of interest for lithium recovery and purification from red mud.

By David Chastka, Isidro Rivera, Shawna Von Stockhausen, Idit Zarchi

The City of Santa Cruz Water Department is replacing the existing Newell Creek Dam inlet/outlet works at Loch Lomond Reservoir in the San Lorenzo Valley. The project will improve the City’s overall operational efficiency, improve system performance, and improve the safety and reliability of storage for the City’s drinking water supply. The project comprises new inlet works* (three new inlets that control and convey flows into and out of the reservoir, and an intake control building), an inlet/outlet tunnel with a 48-inch conduit to convey flows into and out of the reservoir, and a new outlet structure at the toe of the dam. The outlet structure includes a release point for energy dissipation of emergency drawdown flows, a connection to Newell Creek Pipeline, and beneficial releases into Newell Creek. The project also includes a new dam seepage collection and monitoring system and appurtenant structures such as a culvert bridge over the spillway plunge pool to improve access to the new outlet. Notable complex project components include in-water work to connect the new intake shaft pipes to the three new inlets. The project includes one major milestone with a work window regulated by environmental permits that could only be amended/ extended with approvals from those agencies. If not met, the milestone work would have caused significant delays (potentially up to one year) to the project.

Jun 13, 2021

By John Murray, Daniel Ebin, Robert Gould

The Atlanta Plane Train project at Hartsfield-Jackson Atlanta International Airport employed the progressive design-build approach. This provided opportunities for collaboration between the design-builder, design engineer, and owner and the implementation of innovative design and construction approaches. The innovations have reduced risks, allowed for adjustments during design to accommodate new challenges, and provided open-book cost and schedule evaluations. The progressive design-build approach has also allowed for pricing of work to occur in phases—capturing the design/construction challenges as the project evolves and when they are more clearly defined. While this has allowed for pricing to be performed with better project understanding and therefore less contingency, the associated time frame for approvals has required careful consideration to avoid impacts to the schedule. This paper discusses the benefits and challenges of the progressive design-build approach.

Dec 1, 2022

By Kevin Lofftus

The rest potentials of molybdenite electrodes are measured as a function of pH in absence and presence of flotation reagents. The chemicals used include sodium ethyl xanthate, kerosene, dextrin,sodium hydrosulfide, hydrated sodium molybdate, sodium sulfate, and hydrated sodium thiosulfate. The effect of dissolved oxygen is also noted. The obtained data are correlated with the results of micro-flotation tests obtained under similar chemical conditions.

Jan 1, 1984

By Christine E. Turner-Peterson

Pore-filling organic material concentrated uranium to form sandstone-hosted primary uranium deposits in the Jurassic Morrison Formation of the Grants uranium region, New Mexico. Petrographic observations and radiometric ages for primary ore in the Westwater Canyon Member require that the organic material was emplaced early in the diagenetic history of the host sandstone; in fact, organic material was emplaced before major compaction. This inferred early emplacement constrains models concerning the nature and origin of the organic material and thus also constrains models of ore genesis. Reconstruction of the burial history of the basin indicates that Late Jurassic-Early Cretaceous time, the interval of inferred emplacement of the organic material, was probably not a time of hydrocarbon generation and migration. Nuclear magnetic resonance analyses, elemental abundances, and isotopic studies provide further constraints on the nature of the organic material, and data from these studies are consistent with a humic acid rather than an oil origin. In addition, the overall tabular shape of primary uranium orebodies and the way these orebodies are suspended in the host sandstone mimics Recent deposits of humate, the precipitated form of humic acids. The critical clue that favors a humic acid origin for ore-related organic material is provided by the nature and patterns of postdepositional alterations that are spatially and temporally related to primary ore, specifically destruction of detrital magnetite and ilmenite (iron-titanium oxide) grains. Humic acids are implicated in the destruction of iron-titanium oxide grains because these organic acids are one of the most effective natural agents in leaching of Iron from these grains. Thus, timing constraints, chemical evidence, orebody geometry, and the nature and patterns of ore-related alterations favor a humic acid origin and suggest that an oil origin is highly unlikely. Because alteration of iron-titanium oxide grains tracks the pathways of humic-bearing solutions through the host sandstones, it is possible to trace these solutions back to their source. Alteration patterns in the Westwater Canyon Member suggest that the humic-bearing solutions originated as pore fluids in the mudflat facies of the overlying Brushy Basin Member and moved into adjacent sandstones during early dewatering of the mudstones. The humic acids precipitated, by the process of cation loading, in tabular layers. Uranium was concentrated within these tabular layers by complexation with the humic acids to form primary uranium orebodies.

Jan 1, 2013

By H. Sevim

Three transportation and handling alternatives for delivering dry coal combustion residues from power plants to underground coal mines were evaluated technically and economically. The objective was to transport, handle, and inject the residues into the old workings of the mine at a minimum cost. This objective was accomplished in two steps: I) Simulation models were developed and utilized in identifying technically feasible designs in each alternative, 2) Technically feasible designs were economically evaluated to obtain the cost-per-ton of material transported. The designs that provided the minimum cost-per-ton were declared optimal An analysis was conducted for varying distances and tonnages to reveal favorable operating ranges of each alternative.

Jan 1, 1996

By R. Lai

This paper describes the application of a cyclonic flotation column (CFC) for coal cleaning. A CFC makes use of centrifugal force to create a density gradient in a column to augment the froth flotation process. In a CFC, a series of angular helical inserts is attached to the wall of a conventional column and coal slurry is mixed with a series of impellers attached to a central shaft. The hydrophobic froth concentrates near the center shaft and moves upward, while the relatively heavy hydrophilic particles concentrate near the wall and are guided downward by the helical inserts. Results of pyritic sulfur removal from an Upper Freeport coal during CFC flotation are discussed in this paper.

Jan 1, 2000

By C. B. Henderson

The development of slurries of coal and water as a boiler fuel replacing No. 6 fuel oil has been actively pursued at the Atlantic Research Corporation since 1976. Funding for this effort has been provided by the U.S. Department of Energy, the Electric Power Research Institute, and by corporate funds. The name ARC-COALTM has been selected for these slurries. Stable coal-water slurries with bone-dry coal loadings between 62% and 77% have been prepared, evaluated rheologically, and successfully burned in an experimental furnace without the assistance of other fuels. The advantages and properties of these slurries, including combustion results, are reviewed. Also discussed is the pilot line used for processing barrel quantities of fuel and a pilot plant capable of processing 600 bbl/day, currently being designed.

Jan 1, 1982

By T. Emery, D. Sweet, J. Bourgeois, B. Seymour, D. Porter

Cemented rockfill (CRF) is being used to backfill primary and secondary stopes at the Eagle Mine, an underground nickel and copper mine operated by Lundin Mining. National Institute for Occupational Safety and Health (NIOSH) researchers from the Spokane Mining Research Division (SMRD) are conducting cooperative research with the mine staff to determine if the size of a CRF sample affects its measured strength properties. Based on previous research by NIOSH, cylindrical samples of CRF ranging in size from six to eighteen inches in diameter were cast at the mine and cured underground. The samples were later transported to the SMRD laboratory and the Michigan Technological University where tests were conducted to determine the strength and elastic properties of the CRF. To further analyze the relationship between backfill density and compressive strength, different ASTM International compaction techniques were used to cast the samples. For comparison, tests were also conducted on in-situ core samples that were drilled from a stope which had been backfilled with the same CRF mix. The data collected from this study not only improves our understanding of CRF in-situ properties but also helps optimize Quality Assurance/Quality Control (QA/QC) methods for backfill preparation and testing.

Feb 1, 2023