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By R. C. Hopper, A. A. Mathews, T. A. Lang

DESCRIPTION OF PROJECT The Straight Creek Tunnel site is located approximately sixty (60) miles west of Denver, Colorado, on Interstate Route 70 in the vicinity of Loveland Pass, in the Rocky Mountains. The ultimate project will consist of dual two-lane vehicular tunnels with a building at each portal to house mechanical ventilation equipment and other installations. The tunnels run virtually east-west on an ascending 1.64 percent grade for a distance of approximately 8,900 feet, and will pass beneath the Continental Divide at an elevation of about 11,000 feet above sea level. The maximum cover is 1,450 feet and each tunnel is approximately 48 feet wide by 50 feet high as excavated. The work now under construction consists of the North Tunnel, which initially will have two-way traffic. Ultimately it will be the west bound lanes for Interstate 70. The completion of the North Tunnel will be the fulfillment of a long felt need for better communication through the high Rocky Mountains of central Colorado and is a vital link in Interstate Route 70. The early planning for a vehicular tunnel through the Continental Divide began in the late 1930's and between November, 1941 and May, 1943 an exploratory pioneer tunnel

Jan 1, 1997

By M. J. Friedel

The scale-dependent hydraulic properties in a fractured porphyry copper oxide deposit are investigated for relevance to In Situ Leach Mining (ISLM) design. In most well field designs, mine operators assume that hydraulic properties represent a continuous spatial function, or continuum. The problem, however, is that the representative elemental volume, the volume over which hydraulic properties are described as a continuum, is a domain (if it exists) that occurs between end members representing varying degrees of heterogeneity. At the Cyprus Casa Grande mine, transmissivity fluctuations are spatially correlated. This suggests that, at the scale of ISLM, the hydraulic process is heterogeneous, and a typical continuum representation is inappropriate for design. Alternatively, a conditional stochastic approach using the Simulated Annealing (SA) technique is deemed useful for the imaging of heterogeneous hydraulic properties. Specifically, SA preserves transmissivity extremes and spatial complexity, both necessary for accurate conditioning of a flow simulator. Also, the stochastic continuum approach provides an avenue whereby uncertainty (or risk) may be addressed. Currently, the SA weaknesses are that it is computationally time consuming and that uncertainty may increase when simulating under conditions of statistical isotropy. Recognizing that ISLM exerts a dynamic influence on hydraulic properties with time, the mine design should be re-evaluated at intervals throughout the evolution of the leaching process.

Jan 1, 1994

By J. Pinkley

In June of 2002 Hilti North America received the first MSHA permissible approval for usage of a powder actuated tool device in a gassy mine atmosphere. The purpose of this paper is to discuss the implementation of this commonly utilized tool technology in the construction industry, to the underground gassy mining industry over the course of the last 5 years. Prior to June of 2002, underground gassy mining industry had attached materials such as ventilation curtains, power cables, communication cables, signage, and other materials by either manually driving individual spads or nails into the mine roof or rib or by attachment to existing roof bolt bearing plates. The Hilti DX 460 powder actuated tool is portable, durable, and lightweight (4.5 pounds). The Hilti DX 460 powder actuated tool system is powered by Hilti .27 caliber permissible explosive boosters. The energy force of the Hilti .27 booster?s acts on a captive piston principle in the Hilti DX 460 powder actuated tool, that applies the setting force for the direct fastening to the individual fastener chosen for the application by the end user. Each year Hilti can be called upon by MSHA to provide booster materials for re-testing per our Hilti DX PAD 1/00 approval.

Jan 1, 2008

By K. L. Johnson

Networks of monitoring wells were established prior to mining at four longwall mine sites in the Appalachians to monitor the effect of mining on water levels, water quality and well yield. Two of the sites were located in stream valleys and the other two sites were located on hilltops. The depth to the mined seam ranged from 500-850 feet with the deeper cover being associated with the hilltop sites. Maximum declines in groundwater levels during and after mining were an order of magnitude less in the stream valley aquifers than in the hilltop aquifers. However, water levels in hilltop wells located outside the area immediately above the panel were unaffected. Water quality changes in wells as a result of longwall mining were negligible at all four sites. Increases in aquifer transmissivity and well yield were much more pronounced in the stream valley aquifers than in the hilltop aquifers. The significantly larger recharge area for the stream valley aquifers than that for the hilltop aquifers may partially account for the differing responses of these two classes of aquifers to longwall mining. These observations appear to be consistent with the stress-relief fracture model for Appalachian Plateau groundwater hydrology proposed by Wyrick and Borchers in 1981.

Jan 1, 1986

By Katherine Hynard, Colin Eustace

Development quarterly mine plans is generally time-consuming and requires consideration for many operational constraints and competing objectives. With lengthy turnaround times, there is often limited opportunity to adjust the quarterly plan details to account for differences between actual state of the mine operation at the time of execution and expected state at the time that the plan was developed. Actual mining task completion times can vary significantly from the expected task completion times, due to many factors. In the absence of revision to account for differences between the planned and actual state, resource allocations and mining sequences, embodied in the quarterly mine plan may no longer be the best approach at the time of execution to achieve an efficient mining operation. Simulation and optimisation tools can be used to support rapid refinements for development and execution of weekly mine plans. When initialized with an operations data feed to establish the actual state of the mine operation, optimisation models can be used to facilitate both automation and revision of the quarterly plan to produce a weekly or daily plan for execution. This approach can remove much of the manual burden of revision if the existing quarterly plan no longer represents the best approach to meeting production objectives. Following initialisation with mining actuals, simulation models can provide a representation of the range of likely mine operations outcomes. The models can be used to accelerate the planning process by providing visibility of future performance and identifying likely operational issues. They can also be used to test the robustness of the plan with respect to performance variability and response to disturbances. Following identification of issues, simulation models can also be used for evaluating mitigation measures, through automated testing of alternative plans. Integration of mine data feeds with simulation and optimisation tools enables automated optimal responses to variations between the quarterly mine plan and actuals to be tested prior to release of and execution plan and implementation. The use of simulation and optimisation in weekly mine planning will be discussed in this paper with reference to surface mining examples.

Jun 25, 2023

By Van E. Housman, Stephan Hoffman

Introduction Based upon the 1980 Bevill Amendment to the Resource Conservation and Recovery Act (RCRA), a 1986 Regulatory Determination decision, and subsequent rulemakings, the Environmental Protection Agency (EPA) exempted all extraction and beneficiation wastes and twenty mineral processing wastes from regulation under RCRA Subtitle C (hazardous waste) regulations. These twenty mineral processing waste streams were studied in a 1990 Mineral Processing Report to Congress. For purposes of regulatory classification, EPA made special distinctions between extraction/beneficiation and mineral processing. Wastes determined by EPA to be from the extraction/beneficiation of ores and minerals retain the exemption, while wastes found to be mineral processing, except for the “special" twenty mineral processing wastes, fall within RCRA Subtitle C jurisdiction. For those wastes that are subject to RCRA Subtitle C, § 3004(m) of RCRA requires EPA to set levels or methods of treatment, of any, which would substantially diminish the toxicity of the waste or substantially reduce the likelihood of migration of hazardous constituents from the waste so that short- term and long-term threats to human health and the environment are minimized. These treatment standards are developed by EPA under the Land Disposal Restrictions (LDR) program. Under § 3004(g) (4) of RCRA, EPA is required to promulgate treatment standards for any waste that is newly identified or listed as hazardous. As part of the settlement agreement in Environmental Defense Fund (EDF) v. Reilly and Chemical Waste Management, Inc. v. EPA (1992), EPA has agreed to propose a rule by June 30, 1995 and promulgate a final rule by June 30, 1996. This rule is commonly referred to as the "Phase IV" LDR rule and will address newly identified mineral processing wastes. Other wastes that will be addressed in this rule include newly listed dyes and pigments and wood preserving wastes. Therefore, in the Phase IV rule EPA will develop treatment standards for all mineral processing wastes that have lost their Bevill exclusion. EPA is currently collecting information on the waste characterization, treatment alternatives, and disposal capacity data currently available on these wastes. EPA is also soliciting data and information on opportunities for

Jan 1, 1995

By Ray E. Harris

All of the major raw materials (silica, soda ash, limestone, and feldspar) needed to manufacture most grades of glass are found in Wyoming. Additional advantages for the manufacture of glass include the state's geographic location, a well-developed transportation network, a favorable tax structure (no corporate or personal-income tax), and low energy costs. Inadequate local markets and prohibitive transportation costs to other markets have been the major obstacles to developing a glass industry in Wyoming, the least- populated state in the nation. The Rocky Mountain region only recently became a major market for glass, especially for the Colorado Front Range and Utah's Wasatch Front. Currently, changing costs of the production of glass, an increased market for con- tainer glass in the Colorado Front Range, and innovative production and transportation ideas (e.g., production of selected types of glass and bulk shipments of specification-glass pellets) favor developing a glass plant in Wyoming. Thus, the Wyoming State Geological Survey (WSGS) and other state agencies have been conducting studies and contacting investors in an effort to attract a glass-manufacturing plant to the state. Between 1987 and 1993, three locations of silica-sand and -rock deposits were studied in Wyoming (Cassa, Plumbago Creek, and John Blue). Funding was provided by the WSGS operating budget and local and state Department of Commerce economic- development grants. The reports on these areas were released between 1988 and 1993. In 1988-89, a California-based company conducted additional drilling and feasibility studies and prepared to construct a glass plant in Cheyenne, using the Cassa silica source. However, due to losses incurred by some of their other investments, the company did not proceed. In 1997, the Wyoming Science, Technology, and Energy Administration (STEA) contracted a market study for glass manufactured in Wyoming, using information provided by the WSGS. The STEA contacted several major glass producers, and a major glass-producing company began feasibility studies in January 1998, for the construction of a glass plant. In June 1998, bids to supply brown beer bottles to the Budweiser brewery northeast of Fort Collins, Colorado, were submitted by at least two companies that were considering glass-plant sites in Wyoming.

Jan 1, 1999

By Ed Ramsay

The Hill is a cyanidation plant with flotation and roasting. The grinding and treatment have at the present time a capacity of 1400 tons of ore per day and the precipitation has a capacity of 6000 tons per day. The ore is delivered by a 36" conveyor belt and tripper to 8 mill bins having a capacity of 6000 tons. The ore from these bins is discharged onto 20" gathering conveyor belts which are regulated with p.i.v. speed changers to control the belt weight. A weightometer determines the tonnage milled. The feed enters the 8' x 12' rod mill through a rubber lined chute and the product is discharged through a launder to a 7' rake classifier in closed circuit with 10' by 6' hardinge ball mill. Lime slurry is added at the rake classifier to give a strength of .30#/ton. The classifier sand is fed into the ball mill with a scoop feeder and the mill discharge flows in a launder back to the classifier. The classifier overflow is pumped to a 24' by 12' bowl classifier in closed circuit with a 8' by 15' regrind mill. The bowl classifier sands are fed to this mill and the mill discharge is pumped back to the bowl. The bowl overflow at 8% - 200 mesh is the final product from the grinding circuit.

Jan 1, 1975

By Arthur F. Moss

Smallbore tunnels in urban environments often present more technical and managerial problems than major large diameter schemes carried out for transportion, water supply and hydro-electric facilities. The 1.8 km Bath scheme was designed for construction in tunnel using the pipe jacking system. Unforeseen ground conditions meant other techniques were needed during construction. The paper describes the problems encountered and how they were overcome.

Jan 1, 1981

Iron ores may be upgraded by flotation of iron oxides or siliceous gangue using either cationic or anionic collectors. The electrostatic mechanism of adsorption can account for the complex chemistry involved. In industrial practice, only cationic silica flotation is used at present in North America. Some of the seemingly paradoxical phenomena of cationic silica flotation behaviors in meeting the demand for low silica concentrates are reviewed.

Jan 1, 1989

By Michael Mccorkle

The Turnkey Project contracting approach is a very viable project delivery system for many mine and mill owners. Generally speaking, the Turnkey Project approach makes sense when the owner knows what it wants, is willing to accept the contractors judgement on process elements and maintenance standards, and early construction completion/facility stmt-up are of primmy importance. Projects with unclear process and project objectives make poor candidates for true Turnkey applications. If the objectives are unclear, under development or significant refinement, the owner's effort should go into a good schedule "A" package allowing Engineering, Procurement, and Construction (EPC) contractors to develop cost and schedule proposals for the final design ( engi­neering), procurement and construction of the facility. Figure 1 and 2 graphically depict (in general terms) the stan­dard Design-Bid-Build, Construction Management (CM) Fasttrack, EPC, and Turnkey Approach.

Jan 1, 1998

By Leslie M. Burnside, Gene E. McClelland, Roy R. Cellan

Revegetation of neutralized heap leach material in the arid environment of the Great Basin represents a challenge of avail­able technology. The chemical and physical environment of spent and neutralized ore is inhospitable for germination and establishment of desirable long term vegetation. Common soil amendments were tested to dete1mine if the heap material could be made more conducive to plant growth. Decommissioned heap material profile samples were collected and reconstructed in columns at bench scale. The column profiles were amended and subjected to three leaching regimes, and representative meteoric conditions. The soil amendments provided positive results for ameliorating the heap material limitations and providing a medi­um conducive to plant growth. The bench scale study also pro­vided insight for the future of heap leach planning and design with successful reclamation in mind at the forefront.

Jan 1, 1998

By Peter J. Tarkoy

The use of personal computers (PCs) is increasing in underground construction applications, specifically, for estimating, record keeping, construction performance analysis, project cost reporting, and the effective application of construction experience for estimating and aggressive bidding. Applications particularly suited to the PC are analyses of construction performance and differing site condition claims. The advantages of using a PC in the analysis of differing site conditions claims is that the PC: requires quantitative and factual data, allows vast data manipulations, calculations, and sorting, and provides a simple graphic representation of complex data and issues. The restrictions imposed by a PC are conducive to the focus on essential facts, issues, quantitative analyses, and inherently, the truth. As computer thinking is established, a clearer, more precise and accurate focus on the elements of a differing site condition is essential for successful evaluation and presentation.

Jan 1, 1987

By A. Pavlidis

This paper investigates variations of lignite quality attributes with geostatistical methods. The study focuses on lignite from the Southern Field in the Greek province of West Macedonia. The targeted quality variable is the ash water-free content (AWF). A geostatistical model is constructed based on data from 480 drillholes (approximate drill hole spacing of 250m). For each drillhole, the vertical average of the AWF is calculated. The coarse-grained AWF is then modeled as the superposition of a trend surface and fluctuations. The spatial dependence of the fluctuations is modeled by means of the experimental variogram. Kriging estimators are used to determine the AWF values on a rectangular grid, and the uncertainty of the estimates is calculated. Implications of the analysis for the variability of the produced lignite are discussed, and recommendations for additional drilling are proposed.

Jan 1, 2006

ICMM’s vision is ‘a viable mining, minerals and metals industry that is widely recognised as essential for modern living and a key contributor to sustainable development’. The ICMM Sustainable Development Framework provides the basis for achieving this vision by assisting the industry to improve its performance. Two years on from the first SDIMI conference, significant progress has been made in further developing and implementing the Framework. To fulfill their commitment to implement and report performance against the ten sustainable development principles in the Framework, ICMM’s corporate members have committed to report ‘in accordance’ with the GRI 2002 Sustainability Reporting Guidelines and the Mining and Metals Sector Supplement, developed by the GRI and ICMM. While much remains to be done, development of the Supplement and the commitment to reporting mark an important milestone for ICMM and the sector.

Jan 1, 2005

By Y. C. Kim, M. Preston, F. Martino

Because of the high cost of obtaining coal washability samples, it has been difficult in the past to obtain washability variograms. As a result, it could not be determined if the geostatistical prediction tool known as kriging can be applied to predict in situ coal washability characteristics. This paper presents the obtained variogram models for the Upper Freeport coal seam in western Pennsylvania. Variogram model parameters are presented for a total of 27 models. They are for four different variables: float- weight, ash, sulfur, and Btu, at seven different specific gravities: 1.275, 1.300, 1.325, 1.400, 1.600, 1.800, and 1.80,Sink. Based on the obtained variogram results, it can be con¬cluded that all attributes of coal washability show definite spatial correlation structures, and, consequently, geostatistics can be used to predict the in situ coal washability characteristics.

Jan 1, 1990

By Y. J. Wang

The use of controlled recirculation began in the early 1930s. Although this method has been applied in many mines since then, a generalized comprehensive network analysis is still lacking. This paper presents a unique approach in which the ventilation network with a controlled district recirculation is divided into two subsystems: a main subsystem and a recirculation subsystem. The subsystems are analyzed individually, and the results and their relationships are then integrated into discussions of the total ventilation system. The analysis of the recirculation subsystem is facilitated by introducing a nondimensional parameter (A), which represents the ratio of the air quantity for the working face to that for the subsystem. As a result, far and regulator pressures and air power for various recirculation arrangements can be effectively expressed as a function of and the subsystem air quantity. Numerical examples are included.

Jan 1, 1997

By T. E. Garnar

Heavy mineral mining has been a small, but important Florida industry over the past sixty years. Early geologic history of each deposit is similar up to point of deposition in alluvium, deltaic sediments, or along shorelines. Later geological development through reworking and concentration is different for each deposit. The Trail Ridge deposit was formed by reworking Citronelle sediments of the Lake Wales ridge. Post depositional leaching of iron from ilmenite makes Trail Ridge an important source of titanium minerals for TiO2 pigment manufacture. Research leading to the separation and sale of by-product heavy minerals from Florida deposits has been important in maximizing profitability. Advances in mineral dressing technology will lead to future mining of lower grade reserves. Future needs for heavy minerals seem certain to expand, with increased activity in exploration and development of mining operations.

Jan 1, 1972

By Michael J. Rinker, R. V. Nicholson

Waste rock and tailings from a proposed nickel-copper mine were evaluated extensively for potential on-land and under water disposal. Standard humidity cell and column tests were conducted over a two year period and underwater tests were conducted for more than one year. Nickel concentrations or release rates from the waste were consistent with nickel to sulphur ratios in the solids. This relationship provided a tool to assess the risk of metal leaching in wastes using nickel and sulphide assays. Nickel release and mobilization was found to occur for both oxidizing leach tests and under water tests even when pH values exceeded 7.0. Geochemical model calculations showed that iron oxyhydroxide solids can scavenge nickel from leachate and that the nickel inventory can be released from solids at relatively lower, but neutral pH values.

Jan 1, 2000

By Pradip

The development of highly selective mineral processing reagents, which are not merely metal-ion specific, but specific to the particular mineral surface structure, is essential for the exploitation of relatively more difficult-to-process ore deposits, in particular for the separation amongst minerals having the same constituent ion. Both the choice of the functional group as well as the molecular architecture of the reagent determine its selectivity. Several examples are presented in this paper to illustrate the concepts of structure specificity and molecular recognition at mineral surfaces - the concepts crucial to the advancement of the emerging science of reagents design. Recent advances made in the understanding of molecular interactions involved in the synthesis of biomineralized materials are discussed so as to delineate the utility of this approach in the design of selective reagents for mineral separation.

Jan 1, 1994