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By D. L. Johnson

A number of small but rich copper sulfide (chalcocite) ore deposits are located on Michigan's Keweenaw Peninsula. These deposits are considered too small to warrant the capital investment required for conventional mining. However, they are being considered for in-situ solution mining as a way to revitalize the area's once prosperous copper extraction industry. Geology, mineralogy and geohydrology of the deposits have been investigated to determine their suitability for leaching; Three conclusions were drawn from the work. First, the sulfide mineralization is found primarily in fractures (65%) and, therefore, is accessible to injected leach solutions. Second, the ores are shallow, occurring from surface exposure to about 200 meters depth; injection and recovery wells would not have to be excessively deep. Third, the rock was found to have low permeability, in the neighborhood of thirty millidarcys or less. However, preliminary hydraulic fracturing experiments indicate that this will be an effective method for permeability enhancement. In one experiment a permeability increase of 100 times was achieved using a very low injection pressure at shallow depth. Additionally, fracture aperture spacings measured from drill core were correlated with fair success to field permeabilities.

Jan 1, 1989

Operation of a pilot-scale Floatex density separator was studied using a pyrite concentrate slurry feed. Experimental measurements were further utilized in parameterization of a hindered settling simulation model. The model incorporates particle slip velocity calculation and also a separation efficiency function, adjusted to describe the feed material characteristics. The model was used to compute the overflow and underflow compositions when both fluidization bed pressure and teeter water flow rates were varied. In addition, prediction accuracy and the model validity were evaluated. The simulations gave good results when the teeter interstitial velocities were moderate enough to avoid excessive turbulence in the fluidization. Prediction of the cumulative overflow and underflow size distributions in most experiments yielded essentially less than 10% relative error between the sample data and the estimated value of the 50% passing sizes.

Jan 1, 2011

By Nobuharu Isago, Atsushi Kusaka, Kosuke Kawata

"Strong earthquakes occur frequently in Japan, and some rock tunnels have sustained severe damages on their permanent lining. Many road tunnels, which were constructed by conventional steel arch support and timber lagging method, exist in Japan and they need risk mitigation measures against earthquakes as per our empirical knowledge. Many reinforcing measures for deformed tunnels that may be effective against earthquakes are developed; however, behaviors during earthquakes are not fully understood.In this study, static loading tests and numerical analysis, which simulate a loading condition during earthquakes, were carried out to clarify the effect of the countermeasures. The Load-bearing capacity is estimated for the tunnel structures facilitated by the installment of an inverted arch; however, a joint between inverted arch and sidewall become structural weakness. Rock bolts and carbon fiber sheets have a potential able to mitigate the risks of collapse of the lining by the forces from an earthquake.INTRODUCTIONA number of rock tunnels with no apparent unfavorable ground conditions suffered severe damage, including the collapse of their permanent lining, in large seismic events such as the Chuetsu Earthquake in 2004 (e.g., Mashimo 2005). Since these tunnels were considered to exhibit the required structural strength to survive earthquakes, studies are being carried out to clarify the mechanical behavior of tunnels during earthquakes and their damage mechanism (e.g., Kusaka et al. 2009); however, the aseismic design methodology for mountain tunnels has not yet been established.In many cases of earthquake-damaged tunnels, some defects already existed, such as improper construction and deterioration of lining concrete. Although countermeasures are usually implemented against such problems, their earthquake-resistant effect was not fully understood.In this study, static loading tests and numerical analyses to reproduce these tests were carried out assuming that a rock tunnel was affected by the earthquake to clarify the mechanism of the lining damage and the effect of the countermeasures."

Jan 1, 2016

By John Dodd

Corrosion studies in laboratory ball mills and grinding environment simulations produce corrosion rates and total metal removal rates much lower than those recorded in operating production ball mills. The corrosion component of ball metal loss in commercial mills represents less than 10% of the total loss expressed as micrometers/hour of exposure in recent USBM tests. Such small absolute losses are consistent with ball metal loss measured in production ball mill marked ball wear tests to determine effects of corrosion and abrasion resisting properties of alloys in operating mills which indicate that metal hardness and microstructure determine relative metal loss rates of a given situation. The combination of ore characteristics and grinding process dynamics determine metal loss severity. Alloying for corrosion resistance and modification of the milling corrosion environment yield relatively small metal loss reductions. Alloying and heat treatment to produce high hardness and microstructures of high carbon martensite and for cast irons, M7C3 carbides produces the lowest metal losses in typical wet grinding applications.

Jan 1, 1984

By William W. Edgerton, Moussa Wone, David H. Corkum, Carlton M. Ray

"The DC Clean Rivers (DCCR) Project is a 25 year, $2.6 Billion court ordered project to reduce combined sewer overflows (CSOs) discharging into the Potomac and Anacostia Rivers and Rock Creek, and also reduce flooding in the northern areas of the District of Columbia. Like all massive infrastructure programs, DCCR faced technical challenges, management challenges, risks of cost and schedule overruns, procurement challenges, and financing challenges. While DC Water is no stranger to large capital improvement projects (CIP), this CSO Program represents a once in a lifetime event for the Owner requiring the assembly of a single purpose team to implement. Some of the DCCR Project team’s most successful accomplishments to date are attributable to its introduction of early contractor involvement (ECI) to thoroughly vet the work from the perspective of the future constructors, development of functional baselines to share risks that are difficult to price and reduce reliance on geotechnical baseline interpretation during tunnel excavation, and attainment of financing through Municipal Century Green Bonds based on using design criteria of a minimum of 100 year life for the structures to establish intergenerational equity and fairness. This paper will discuss these innovations in detail and provide some sets of recommendations for the underground industry on when and how to use different approaches to better manage projects of this magnitude. INTRODUCTION The District of Columbia Water and Sewer Authority (DC Water) is an independent multi-jurisdictional authority that was established in 1996. Its primary mission is to provide water distribution services to more than 640,000 residents in the District of Columbia (District), and sewer treatment and disposal to 1.6 million residents of the District, Montgomery and Prince George’s counties in Maryland and Fairfax and Loudoun counties in Virginia."

Jan 1, 2016

By J. H. Mackey

"Where can I obtain a reclamation bond today?" "Who is writing your bonds?" These questions are common and heard frequently. The fact that the Society of Mining Engineers has determined that two of the five environmental topics reviewed at the 1989 Annual Meeting relate to reclamation bonding indicates to me that those who are involved in the coal industry, no matter what capacity, remain very cognizant of the reclamation bonding dilemma.

Jan 1, 1989

By D. B. Sikka

Porphyry type copper ± molybdenum deposits typically occur in the Phanerozoic rocks and have been well documented. During the past two decades a number of porphyry type Cu ± Mo deposits which range in age from 1055 ± 35 Ma to 2970 Ma have been identified in the Precambrian rocks of Australia, Canada, China, Finland, India, Namibia and Zambia. Kalanjkhand porphyry copper deposit M. P., India which is estimated to contain 789 million tonnes averaging 0. 83 percent Cu (millhead-grade); 0.004 percent Mo; 0.2 gm/t Au; 6 gm/t Ag and a cap of 7.532 million tonnes of oxide are averaging 0.8 percent Cu. The economic potential of the expanded copper mining milling, smelting and refining complex to be built in the future at Kalanjkhand, which is the largest porphyry copper deposit discovered to date in the Precambrian rocks of the world is presented.

Jan 1, 1992

By R. L. Beatty

The Bond International Gold (BIG) Colosseum Gold Mine was discovered in 1865, but no recorded production occurred until the 1930's, with production approximately 19k9 (615 oz) of gold. The mine was closed in 1942 as a non-essential industry during World War II. The property was acquired by Dallhold Resources in mid 1986. Construction of a 1.1 million Mt carbon-in-pulp, cyanide mill started in November, 1986, and was completed in September, 1987. Minable reserves are estimated to be 9,560,831Mt (10,539,000St), with an average grade of 2.1 g/Mt (0.062 oz/st). This paper describes a general view of process flow and plant equipment, as well as a look at the maintenance and operational problems encountered in the fist six months of operation.

Jan 1, 1989

By Carrie Smith

The 2025 Women in Mining USA National Conference, held April 15-18 at the Grand Hyatt Riverwalk in San Antonio, TX, brought together hundreds of professionals for a fourday event focused on empowering women and creating space for all individuals in the industry. Under the theme “Empowering the Future of Mining,” the conference served as a dynamic platform for professional development, knowledge-sharing and cross-sector collaboration. Organized by Women in Mining USA (WIM USA), whose mission is to foster equity, sustainability and leadership in mining, the event featured an extensive agenda including workshops, keynote speeches, panel discussions and networking opportunities. Attendees ranged from industry veterans to emerging professionals and students, united by a shared commitment to progress within one of the world’s most essential and traditionally maledominated sectors.

Jun 1, 2025

By R. Larry Grayson

In an interdisciplinary research effort at West Virginia University, the Mine Management Support System (MMSS) is being developed as a window-based shell that may be used for the integration of a myriad of applications software. A number of integral components that focus on enhancing operational decision making are being developed as well. MMSS includes a flexible and robust work scheduling system that assigns the "best," qualified workers to the highest priority jobs on a shift while considering many practical and dynamic parameters affecting the assignments. A consultation system has been developed to help solve operating problems using management-preferred responses and the latest available information on operations.

Jan 1, 1992

By D. K. Denton, M. J. Friedel, D. F. Scott, T. J. Williams

Spokane Research Center personnel have been investigating the use of seismic tomography to monitor the behavior of a rock mass, detect hazardous ground conditions, and assess the mechanical integrity of a rock mass affected by mining. Seismic tomography can be a valuable tool for determining relative stress in deep ( > 1220 m) underground pillars. If high-stress areas are detected, they can be destressed prior to development or avoided. High-stress areas can be monitored with successive seismic surveys to determine if stress decreases to a level where development can be initiated safely. There are several benefits to using seismic tomography to identify high stress in deep underground pillars. The technique is reliable, cost-effective, efficient, and non-invasive. Also, investigators can monitor large rock masses, as well as monitor pillars during the mining cycle. By identifying areas of high stress, engineers will be able to assure that miners are working in a safer environment.

Feb 24, 1997

By J. J. Antony

As the first wave of precious metal heap leach closures and reclamation projects occur, a number of companies are being hit with costly surprises. While this paper refers specifically to U.S precious metal projects, it could be conceptually directed at copper leach operations and acid rock drainage (ARD) problems on an international basis. ARD is Mother Nature's version of heap leaching, only with different products and timing. Although many precious metal deposits tend to be small in comparison with some base metals systems (porphyry copper deposits), adjacent or nearby discoveries have extended the operating lives of numerous precious metal mines. Now, depleted reserves, several years of relatively depressed precious metals prices and some properties with technical difficulties have resulted in numerous mine closures. As a result, our industry is getting a diverse and comprehensive initial look at mine closure and final reclamation. The situation has been further complicated by the evolutionary trend in regulations and their enforcement and increasing public and political awareness of all environmental issues. Concurrent (proactive) vs. deferred (reactive) reclamation and a realistic early appraisal of ultimate reclamation and closure requirements, not just regulatory compliance, need to be a part of project design. The U.S. and Canada are the current fertile testing grounds and have set the design, regulation and closure standards for the next wave of operations in Latin America, the CIS (?), etc.

Jan 1, 1994

By John E. Kinnison

The Mission mine, located in southern Arizona near Tucson, is a recently developed open pit which produces 15,000 tons per day of copper ore. The mine lies on a wide and gently sloping bajada sweeping northeasterly from the Sierrita mountains. It derives its name from the nearby Mission San Xavier del Bac, built circa 1700. The ore body is everywhere covered by about 200 feet of alluvium, as are the adjacent Pima and Palo Verde mines. The geology of the Mission deposit is known principally through the study of diamond drill holes spaced 150 to 300 feet apart. The open pit is in an infant stage and has not yet revealed much of the deposit, although information obtained there by the operating staff, and from a few thousand feet of exploratory underground workings, has added significantly to the general fund of knowledge. Permission to publish was granted by the American Smelting and Refining Company. I am indebted to Kenyon Richard and J. H. Courtright for criticism of this paper and for their direction during the several years in which I studied the Mission deposit. Acknowledgment is given to consultant in petrography, Robert L. DuBois of the University of Arizona. The only previous publication pertaining directly to the geology of file Mission deposit appeared in 1959 (Richard and Courtright), and may not be everywhere readily available. Cooper (1960) has published a short paper on the district

Jan 1, 1963

By Edward C. Dowling

The advance of science and technology influences the modern economy in countless ways. Older industries must adapt to changes in the marketplace, while new industries are born by applying new technology to meet consumer needs. In light of declining head grades and increased unit costs in the US minerals industry, new technological developments in the production environment are paramount to maintaining a competitive footing in the international marketplace. Micro-engineering research provides the transition between the knowledge base and the application of new technology on the production level. Economic considerations The primary goal of technical development in the production environment is to reduce unit operating costs. Simply stated, this is accomplished by improving operating efficiencies and productivities on the production level. The goal of micro-engineering research in the production environment is to evaluate promising technologies and develop the criteria necessary to apply them in operations. As such, this process is the first step toward innovation and discovery. Generally, the micro-engineering research is followed by macro-engineering development. In the production environment, there are generally more development projects than can be accomplished in a timely manner. Usually, this is the result of financial and human resource limitations. Consequently, it is necessary to prioritize the work such that the most beneficial projects are accomplished first. By performing a discounted cash flow analysis and using benefit-cost ratios (for non-mutually exclusive alter¬natives) or net present value criteria (for mutually exclusive alternatives), the projects can be rated from best to worst. In this way, the financial and human resources can be best allocated to first complete those projects giving the highest returns before moving on to other activities. Moreover, this information is a prerequisite for management to justify additional financial or human resources.

Jan 1, 1992

By William Laird

In the process of mining coal today, our greatest asset, the coal miner, is faced with the indirect and direct consequence of underground mining operations. The indirect considerations may be the rank of the coal seam, the amount of overburden, geological factors, seam permeability and cracks. The introduction of newer, bigger and faster coal-producing face equipment having the capability to cut or rip through the bedding planes, cleats and micropores of the coal seam brings about rapid liberation of gas accompanied by greater concentrations of coal dust, has exerted a direct consideration and greater demand upon mine ventilation systems and dust control. The purpose of mine ventilation is to provide sufficient pure air to the miners working underground and to dilute, render harmless, and carry away all the dangerous and noxious gases. The mining operations which create coal dust are cod cutting, drilling, blasting, loading, hauling, dumping and movement of face equipment. The created fine dust causes the propagation of explosions. When quantities of coal dust with no methane present are raked in a sufficiently dense cloud in the presence of a source of ignition, an explosion is possible.

Jan 1, 1980

By M. Nichols

Where am I? Where are they? Where is it? These are the fundamental questions that need to be answered in managing people and resources. This paper explains how GPS positioning technologies answer those fundamental questions and provide better information management from initial exploration work through daily mine operations to reclamation work and environmental monitoring.

Jan 1, 1998

By R. J. Sweigard

Productive and beneficial use of reclaimed surface-mined land is a concern of industry, government, and the general public. An investigation was conducted of current mined-land planning practices to aid in the development of a procedure for evaluating postmining land use potentials. This investigation considered both the industry and public planning approach to mined-land planning and was based primarily upon three case studies conducted in various regions of the United States. The site planning process that was developed during the investigation is iterative in nature and has been designed specifically for the mining industry. It centers around preliminary studies and data collection, development of land use alternatives, and the evaluation of alternatives. Use of this process facilitates the evaluation of economic, environ- mental, and social impacts of postmining land use alternatives. In this paper, the process is presented along with a description of its development, application, and significance.

Jan 1, 1984

By T. R. Ellis

Australia’s mineral valuation code continues to evolve, while mineral valuation standards are also being written for Canada and Southern Africa. The author is leading a task force for writing the extractive industries addition to the International Valuation Standards. Meanwhile, the International Accounting Standards Board is continuing the development of an extractive industries addition to its International Financial Reporting Standards, with an emphasis on valuation reporting. This paper analyzes the need, content and ownership for a U.S. minerals appraisal standard in the context of both these developing international standards and also existing U.S. regulations and appraisal standards. The author provides many questions for research and debate.

Jan 1, 2003

By C. M. Sliepcevich

This paper is a brief status summary of investigations by the authors over the past decade to develop a continuous process for recovering' high purity metal powder from pregnant solutions by gaseous reduction at elevated temperatures and pressures. Although these studies included extraction of other metals such as nickel, silver, and gold, this presentation will be confined to the hydrogen reduction of acidic and ammoniacal solutions of copper. The continuous hydrogen reduction process (CHR) described herein enjoys the environmental advantages of other hydrometallurgical processes but, in addition, provides a substantial benefit in fuel economy over competing processes. As was recognized by Schaufelberger in 1956, for a given amount of fuel a continuous hydrogen reduction process has the potential for producing four to six times as much metal as an electrolysis process (1). Although hydrogen reduction of metal salt solutions has been known for more than a century, extensive development work leading to commercialization was not initiated until the 1950's. Since then, commercial applications relative to other extractive techniques have been minor and have been confined to batch or to continuous, completely-mixed autoclaves. By contrast, the process described herein utilizes a continuous, tubular reactor which is operated in modified plug flow so that only limited and localized backmixing occurs. Thus, gradients in concentration, temperature, and pressure exist over the length of the reactor, the presence of which can be utilized to advantage for achieving high conversions and product quality (2, 3).

Jan 1, 1975

By B. J. Timmons

Depending upon which of two letters describing the theme of the session I chose to honor, the subject choices because either one or three. They were: "Applied Research and Exploration and Discovery" or "Applied Research in Exploration and Discovery." The final choice; to partially ignore both of them. That minor difference in meaning may be appropriate here, inasmuch as very minor research/exploration differences may also have profound impacts on discovery. To further set the stage, I consider myself an Industrial Minerals geologist, and more specifically primarily associated with basic construction materials crushed stone and sand & gravel. My remarks will apply primarily to those materials. Therefore, when the discussion instructions included emphasis on beneficial aspects (to name a few): "drill target definition; elimination of ore potential; ore forming environments; alteration studies, and isotope analysis," problems became apparent. Evidently, and although this was a form letter, the drafters of that letter had no idea what was involved in research for a construction materials source. My task may be great.

Jan 1, 1995