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By M. S. Enders

The McDonald deposit is a volcanic-hosted epithermal gold resource that is estimated to contain 251,000 kg of gold in 375 Mt of ore at an average grade of 0.7 g/t gold. Phelps Dodge exploration geologists, working for the Seven-Up Pete Joint Venture, discovered the deposit in 1989. By the end of 1992, 494 drill holes for over 113,000 m of drilling, bulk sampling, soil geochemistry, geophysics, metallurgical testing, engineering, and environmental studies had been completed to support feasibility studies. The discovery of McDonald required vision, persistence, and commitment of everyone from the geologist on the drill rig to the senior management of the company.

Jan 1, 1995

By Christopher Mark

The Analysis of Retreat Mining Pillar Stability (ARMPS) program has been used to evaluate room and pillar retreat mining layouts since it was first released in the mid 1990s. After the Crandall Canyon mine disaster focused attention on the importance of pillar design, ARMPS became an essential component in most Roof Control Plans developed by mine operators. In 2010, NIOSH released ARMPS version 6, which features a ?pressure arch? loading model for deep cover room and pillar mining. NIOSH has also provided general guidance for using ARMPS, including design criteria based on statistical analyses of an extensive case history data base. Many real-world retreat mining scenarios entail mining configurations that ARMPS does not directly address. Some of these situations that the MSHA Roof Control Division (RCD) has encountered in the course of its reviews of more than 100 ?complex and non-typical? plans are ? Unmined pillars are left at the mouth of a retreat panel that function as a ?composite barrier pillar? ? The floor is extracted on retreat, increasing the mining height ? More than one row of bleeder pillars is left in an adjacent, previously mined panel ? A retreat panel is located above or below a gob area in a previously mined seam ? Bleeder pillars are partially extracted on retreat RCD has developed solutions that allow these situations to be fitted into the ARMPS framework, and these are presented in this paper. Also discussed are some of the rules of thumb that have been developed for various input parameters, such as the treatment of inseam rock and slab cuts into solid coal.

Jan 1, 2011

Building block cave operations involves significant commitments to capital and time before arriving at completion or full scale production. The focus of the mine planners is habitually to minimize the upfront capital and achieve target development rates and construction dates. However, management of the construction of block cave projects requires understanding of the strategic/tactical decisions that the project planners can take to increase the value of the project and cope with schedule risks. As block cave projects involve development of vertical and lateral access to the underground footprint and ore body, more attention to uncertainties is required as most of those projects need to confront delays leading to a decrease in value. The standard process of development and construction scheduling is often not planned with provisions to realise uncertainties in the construction phase. Uncertainties and risks such as poor ground conditions and equipment breakdowns are the primary reasons for schedule slippage. As a result most of these projects experience delays. In order to mitigate risk to the project schedule, we centre our attention on increasing the value of the project by spending more money upfront and improving the schedule rather than focus on minimizing the upfront capital. Scenario-based simulations along with project appraisal methods hold great promise to address those challenges and enable mine planners to make better decision and enhancing project value. This paper will present a hybrid simulation based approach to model the process of development and construction based on discrete event (DES) and continuous based simulations (CBS). Such simulations will be conducted for scheduling multiple development headings (Apex, undercut, extraction, and haulage levels). Two scenarios are utilized to investigate the impact of risks on schedule and how flexibility in construction can be incorporated to minimize delays: (1) The bench mark scenario is created based on actual data from an existing case study. (2) The flexible scenario is an alternative way to use primary production infrastructure (Ore Handling System) including conveyer drifts, conveyer belt, and a gyratory crusher in the construction process and that requires the system to be in place before starting lateral development in the footprint. As a result, a truck-load system versus a conveying system will be studied to observe the gain in construction speed and to estimate the premium cost for mucking rock from headings and drawbells and transporting it to surface. Such strategic flexibility would be part of the original budget to make the tactical flexibility available during construction. Continuous cash flow models are used to evaluate and compare the scenarios. This study is an example of how new techniques in planning can be used to support decision-making processes in block cave design.

Aug 1, 2013

From 1886, the first year shipments were recorded, until 1939, the Leadville district produced over 3,500,000 long tons of manganiferous ore. Of this total, metallurgical-type ores comprised 27 percent and manganiferous iron ores suitable for fluxing in lead smelters made up 73 percent. In 1939, the Bureau of Mines, as part of the strategic minerals investigative program being conducted at the time, requested the Mineral Industries Survey Section of the Mining Division to make a comprehensive study of the manganese resources of the Leadville area. This investigation, owing to the caved and flooded condition of the underground mine workings, was necessarily confined to a study of old maps, production records, and geological reports, and the results were published as an Information Circular in July 1940.

Jan 1, 1949

By Donald L. Freed

Design, development, factory test, and in-mine evaluation plans are presented for an Automated Extraction System (AES) that has been designed to fill needs which are present in the Mining Industry. The philosophy of design and proposed operation of the machine, as well as the relationships between these factors, and final machine configuration are reviewed. The AES is designed to overcome production problems resulting from the regulation of roof control, clean-up, ventilation, dust suppression, and operator protection required by the Federal Coal Mine Health and Safety Act of 1969. The design permits more continuous operation and greatly improves operator safety. The machine is a full-face drum-type continuous miner which includes self-advancing, continuous temporary roof support. Onboard self-advancing face ventilation, dust suppression, and air scrubbing equipment are also included in the design. A further improvement over existing equipment is the incorporation of an automatic programmed cutting cycle control system. All mining functions including movements of the roof support system are handled by this automatic system.

Jan 1, 1977

By Raymond T. Moore

The Federal Coal Mine Health and Safety Act of 1969 (FCMHSA) begins with this statement: "Congress declares that the first priority and concern of all in the coal mining industry must be the health and safety of its most precious resource -- the miner; . . ." At the Federal level this responsibility is shared by the Department of the Interior and the Department of HEW. The health research and standard setting activities under the Act are largely the responsibility of the Department of HEW, and with the exception of Title 4, Black Lung Benefits, have been delegated to our Institute, which I will refer to henceforth as NIOSH. In addition, we bear certain joint responsibilities with the Department of the Interior. These include dust sampling and respirator approval. To complete the picture, the Department of Labor has recently assumed Black Lung Benefit respon¬sibilities from the Social Security Administration under Title 4 of the Act.

Jan 1, 1974

By German Zambrana

The solution of the problem of beneficiation of cassiterite from its primary ore deposits is of fundamental importance to Bolivia. The process today involves a gravimetric treatment of the ore followed by sulphide flotation. During the last year, a cassiterite flotation stage has been added in several plants to treat the slime tailings. Although cassiterite flotation is already economical for the slime tailings and the mechanism of the process are understood, it is felt that further research could improve the results. In the past, considerable amount of research and test ark has been performed to select appropriate collectors to improve recovery, to increa¬se the grade of tin in the concentrate, to minimize the effect of metallic ions like Ca+2, Fe+2 and Fe+3 which prevent flotation, and to increase the pH of the pulp which now it can not be higher than 3.0. It has been reported that the halogen salts (1) like NaCl exhibit special surface affinity for cassiterite but none for quartz. These effect seems to be favourable for the selective flotation of cassiterite from silica minerals. In view of these preliminary results it was decided to follow the research accordingly: OBJECTIVES The objectives of the present investigation are: 1. 0 evaluate the influence of NaCl salts in quartz and cassiterite flotation.

Jan 1, 1971

By M. D. Johnson

The San Andres mine, located in the western mountain region of Honduras, Central America, contains epithermal gold mineralization as disseminations, in quartz-chalcedonic veins and stockworks. Host rocks include a thick sequence of Cretaceous to Tertiary conglomerates, sandstones, rhyodacite tuffs and andesites. Mineralization is controlled by northwest and northeast striking, normal faults and fractures which dip steeply east and west. Currently, 500 STPD of 1. 93 Grams/MT gold ore is being open-pit mined from the conglomerate and andesite. The mine is at the west end of a mineralized zone that can be traced over an area of approximately 1.5 square kilometers.

Jan 1, 1993

By R. H. King

Suboleski and King (1990) analyzed the reasons for the dramatic increase in underground coal mine productivity during the last 10 years. This paper examines whether this increase can be extended. The paper forecasts whether the mix of technological, procedural and other factors that produced the increase will change in the future. The forecast is based on the base case and spreadsheet production model described in the previous paper.

Jan 1, 1991

By N. Saeidi

"For a mine section comprising 100 different stoping activities, there are ~10158 different possible stoping sequences to explore in the mine schedule optimization search and this figure is indicative of the challenge posed in maximising profitability through mine schedule optimization. Any viable excavation timetable must satisfy all conditions that will constrain feasible sequences. In general, consideration of additional constraint will tend to reduce profitability. Geomechanical constraints on mine schedules, introduced with the aim of avoiding excavation instabilities, can be established for underground mine schedule optimization processes but, currently, this is done only rather crudely; precedence relations between excavation activities (stoping or development) are encoded to produce particular stope sequence patterns (e.g. ‘chevron’ or pyramidal sequences).The work reported aimed to investigate automated processes for formulation of such geomechanical constraints. The timetable optimization approach to the problem precipitated a fresh look at time dependent, and excavation sequence dependent, deformation. Abundant evidence emerged that supported the notion that any methodology developed that failed to account for such time and sequence dependencies was itself bound to failure. Yet, it was also recognised that any deviation at all from an assumption of linear elasticity for geomechanical numerical modeling, adopted to inform geomechanical constraint formulation, would rapidly lead to impractical levels of computational effort.Thus the approach presented here represents a compromise: the elastic stress fields induced by individual mining activities are computed for each activity, independently considered within a computational domain identical to that of all other activities. These are stored in a database. Instability risk for a specific sequence of mine activities can be assessed through superimposition of stress fields drawn from the pre-computed database. Time stamps allocated to events corresponding to the excavation processes permit the conversion of the sequence of elastic stress fields into a time table of stress fields. For specific locations within the computational domain, the aggregate effect of the sequence of mine activities leads to stress-time histories having a castellated appearance, a result of the near instantaneous response of an elastic medium to the excavation perturbations. Time dependent deformation responses are crudely allowed for through the re-profiling these castellated histories through graphical construction of curved responses, where the curve gradients are related to a viscous parameter. Such curves form the basis for a geomechanical constraint formulation to be adopted for mine schedule optimization."

Jan 1, 2015

By L. Sandbak

The Turquoise Ridge Joint Venture (TRJV) is located in northern central Nevada, and is situated within the Basin and Range province, near the northeast end of the Osgood Mountains (see Figure 1). The TRJV mine consists of typical Carlin type- gold mineralization characterized by low strength rock of altered limestones, siltstones, and mudstones. The weak nature of the ground facilitates the underhand cut and fill mining methods. TRJV has been working to optimize ground support and mechanize top cut drift sizes and eliminate operating hazards associated with jackleg drilling. Safety Factor analysis based on bolt strengths has allowed us to pursue larger sized top cut drifts and to evaluate bolt length sizes and spacing. Switching from jackleg sized drifts of 10?W x 10?H to a mechanized 12?H x12?W top cut drift design has the potential to decrease overbreak, provide more uniform drift design sizes and bolt patterns, and increase ore production by at least 38%.

Feb 23, 2014

By Eltefat Ahmadi

Iron-free titanium oxycarbonitride (TiOxCyNz) is a promising feedstock for production of titanium tetrachloride (TiCl4) at low temperatures. In this study, the effects of leaching variables such as temperature, time, particle size of staring material and concentration of the leaching solutions were evaluated on iron removal from nitrided Malaysian ilmenite by Becher process. The nitrided ilmenite was prepared by isothermal reduction with graphite at 1200 °C for 3 h in H2-N2 atmosphere. The aerated leaching experiments were conducted at 50–90 °C with addition of 0.3–2.0 wt% of NH4Cl catalyst. The highest extent of iron removal (XFe) was obtained at about 96.2% for the sample leached at 90 °C for 7 h with 2.0 wt% NH4Cl. The iron concentrate and titanium oxycarbonitride product were characterized by ICP-OES, XRD, XRF and SEM-EDX analyses. The results indicated that the aeration leaching process was a successful route to prepare low-iron titanium oxycarbonitride.

By R. J. Rotzinger

The Gibraltar Mine and Mill facility were commissioned in 1972 by Gibraltar Mines Ltd utilizing a flowsheet consisting of two stages of crushing followed by a rod mill / ball mill grinding circuit. During operations a number of opportunities were evaluated to expand the mill capacity; however, the economics of the day did not allow any of these projects to proceed. The mine continued to operate until late 1998 when it was shutdown and put on care and maintenance due to low commodity prices. Taseko Mines acquired Gibraltar in 1999 and in 2004, with the improvement in the metal markets, made the decision to restart operations. During the restart planning a number of opportunities for mill improvements and upgrades were identified and, after operations were successfully restarted, the decision was made to once again review expansion opportunities for Gibraltar. Taseko evaluated various expansion alternatives eventually deciding to install a SAG Mill, convert the existing rod mills to ball mills and distribute the SAG discharge to the resultant six 6 parallel ball mills. This paper discusses the design, implementation and commissioning of the SAG mill grinding circuit.

Jan 1, 2012

By G. J. S. Govett

Dwindling near-surface mineral reserves emphasize the need for the development of exploration techniques capable of greater depth penetration; geochemical techniques tradition- ally have been restricted to the search for deposits having at least a sub-outcrop expression. Rock geochemical techniques developed in Cyprus in 1967-1968 recognized anomalous conditions in volcanic rocks up to one mile from an ore de- posit. Research by the Exploration Geochemistry Group at the University of New Brunswick has shown that some massive sulphide deposits in New Brunswick have well-defined halos of major, minor, and trace elements in the host rocks extending up to 1,200 metres (4,000 feet) laterally along the same stratigraphic horizon, and up to 450 metres (1,500 feet) vertically in hanging wall rocks which apparently post-date mineralization; well-defined halos have also been found in foot- wall rocks. Some of these halos are readily identified as individual elements or as element pairs; others are so subtle as to be recognizable only through computer-calculated multivariate analysis. Research continues to extend the dimension of rock geochemical halos for regional exploration and for identification of more restrictive anomalous conditions which may closely define the location and extent of buried sulphide deposits.

Jan 1, 1975

By Yuliy Rubinstein

"The paper presents a analysis of the history and the trends of development of flotation apparatus. The laws of their evolution are stated and the place and role of column flotation are indicated. It is demonstrate development and different design of column apparatus. The major parameters of column cell such as diameter and height are discussed. Options are proposed on optimization of hydrodynamic characteristics of columns with large-capacity cells. High efficiency of columns with cell height of 4-6 m is shown on examples of coal preparation. A new generation of multi sectional column cells has been developed. In the cells are zones with different aerohydrodynamic parameters: combined in the machine are co-and counter- counter flows of phases. The transition from single-chamber column to multi-sectional apparatus makes it possible to create favourable hydrodynamic and aeration regimes in each section of the column dependent on the pattern of material distribution by floatability. Efficiency of application different designs column apparatus uses shown on the example of enrichment of various non-ferrous metals ores and coal. The principles of mathematical simulation of the flotation process are developed. A scaling-up procedure for column cells was based on flotation macro- and micro- dynamics simulation.INTRODUCTIONColumn flotation is considered to be one of the most significant achievement in the field of mineral processing in the end of last century. We cannot but agree with this statement but would like to understand what underlies this success. History of the flotation column can not be considered in isolation from the development of flotation apparatus on the whole. It can be argued that the first attempt to switch from oil flotation to the use of bubbles during flotation was performed Bessel brothers in 1877 (Berlin patent 42 class 22, July 2) and in 1886 (Berlin patent 39,369 May 12). According to these patents, the crushed ore was mixed with oils , hydrocarbons and water. Then the pulp received in this way was heated up to boiling . Air bubbles and steam formed during boiling facilitate the flotation of ore particles coated with oil (first patent) or bubbles been generated by the reaction of lime with acid (second patent). The evolution in the design of the flotation apparatus incorporates the following key stages. Further development is connected with the Francis Elmore’s idea to use gas bubbles received at water electrolysis (UK, 13578; 1904). This method was not introduced then, but much later, in our time and on the essentially new technical basis it found a use for sewage treatment (electroflotation). Gas bubbling under vacuum patented also by Elmore (UK, 17816; 1904) obtained a practical use. It should be noted that the method did not lose its importance till now. The design of the camera has been surely optimized (Glembotskii etal, 1963). A year later A. Macquisten (UK, 26712) developed pressure (compression) flotation. Thus, the H.Sulman, H.Picard, D. Bell’s (US, 853120, May 29, 1905) basic patent and the adjoining T. Goover’s patent 1910 (US, 953746) formed the basis of the first and most important element of modern flotation: flotation with air bubbles sucked in from the environment. In 1914, J.Callow received a patent for on an apparatus where air was sparged through the porous false bottom of the cell ( US, 1104755). Woolen fabric folded four times was fixed on a perforated metal frame to be used for air sparging (Gaudin, 1932). The following year Durrel created the prototype of the injection (ejector) apparatus. The jet aerator made it possible to significantly reduce the size of the bubbles, in comparison with the filter cloth. An apparatus with slurry pre-aeration in an airlift prior to feeding into separation cell was developed Wagner in 1917 (US, 1235083). And finally, the first column apparatus with a counter-current of slurry and air was developed by M. Towne and S. Flynn in 1919(US, 1,295,817). ("

Jan 1, 2018

By Jerry Tien

Mine regulators are normally used for proper air distribution in underground mines. They are deliberately introduced resistance in the regulated airway, and by altering sizes, they can distribute specific air quantities to regulated splits and free splits (4, 5). The enactment of the Federal Coal Mine Health and Safety Act of 1969, the Federal Mine Safety and Health Amendments Act of 1977, and the regulations adopted by the Mining Enforcement and Safety Administration (now called the Mining Safety and Health ministration) prompted greater discussions of optimal mine regulator locations because of the Act's stringent ventilation requirements (2, 3). For example, by requiring the separation of the air used in the belt haulage entries from the intake and return airways, the regulations required the creation of a third type of airway---the neutral airway, as opposed to the intake and return airways, adding to the complexity of a mine's ventilation network. It is the intent of this report to show that panel regulators should be located in intake airways at the neck of a panel for a blowing fan system and in return airways at the neck of a panel for an exhausting fan system in order to achieve optimal air control. A computer simulation model is used to determine optimal mine regulator location.

Jan 1, 1983

By Richard W. Patton

With the advent of the Clean Air Act and the installation of flue gas desulfurization (FGD) equipment (scrubbers) on coal fired power plants, the management of solid wastes has taken on added importance. Aside from the large amounts of fly ash and bottom ash usually generated, large quantities of liquids in the form of scrubber sludge are also produced. These wastes must be disposed of within the constraints of land and water quality regulations. This paper describes the practices adopted by the electric utility industry in denting with this problem, including methods of generation and treatment, quantities and characteristics of the materials, and transportation and disposal practices. The paper also briefly describes final product characteristics and several applications for commercial utilization and land reclamation.

Jan 1, 1983

By Mike Fontaine

The success of a project is defined by meeting the financial performance objectives of the business case within a stipulated timeframe. Early in design, little information is normally available; the uncertainty introduces risk to the project outcome. Using a range of risk management tools and techniques, a project can be developed from front end loading phases 1 through 3 (FEL1–FEL3), and project implementation (FEL4) and then into operations with an optimized probability of success. For every project element, the risk management framework embodies: establishing a context; assessing risk (identify, analyze, and evaluate); and treating risk. Embedded within design activities, this process mitigates or eliminates risks. Monitoring and control, as well as extensive communication and consultation with stakeholders, is integral to the risk management process.

Jan 1, 2015

By D. E. Wolfson

As part of its overall program of coal-carbonization research, the Bureau of Mines is studying the coking properties of coals from various fields of this country. Few of the coals included in this survey are used for the manufacture of metallurgical coke, although some well-known coking coals necessarily are tested to provide comparative data, particularly on blending properties. The overall objectives of the study were given in detail in a previous report.3/ The inherent suitability of coal for metallurgical purposes, as distinguished from economic considerations, depends primarily on (1) the available reserves, (2) chemical composition, (3) preparation characteristics, and (4) carbonization behavior. These items are considered in selecting coal for carbonization tests.

Jan 1, 1956

By John Furness Park

This paper, which describes the mining methods and practices at the Jarbidge mines of the Elkoro Mines Co., is one of a series of papers being issued by the United States Bureau of Mines on mining methods and costs in various districts throughout the United States. LOCATION AND HISTORY The Elkoro Mines Co.'s property is located at Jarbidge in the northeast corner of the State of Nevada (fig. 1). The camp is 9 miles south of the Idaho line; the nearest railroad point is 70 miles to the northeast at Rogerson, Idaho. A road leading to the south and connecting with Deeth, Nev., is passable during the summer months; the heavy snowfall which generally takes place early in the winter usually closes the road until the first of July.

Jan 1, 1931