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By Theodore S. Jordan

The discovery of a major porphyry-type copper deposit on the Papago Indian Reservation in Pinal County, Arizona was announced by El Paso Natural Gas Company in 1968. The deposit, known as the Lakeshore Property, contained an estimated 470 million tons of sulfides and oxides averaging 0.75 percent copper. History and Geology of the area have been described by Harper and Reynolds (1969). El Paso subsequently&apos; entered into the agreement for joint development of the property with Hecla Mining Company, with Hecla as the operator. The ore body consisted of three types of mineralization: 1) Disseminated Oxide Ore, <1% Cu 2) Disseminated Sulfide Ore, <1% Cu 3) Tactite Ore, >1% Cu

Jan 1, 1985

By Colin C. Brooks

The Ok Tedi gold/copper deposit of almost 800 million tonnes was found in I968 because at that time technology had just developed sufficiently to enable exploration of such an area, world markets and prices for copper encouraged exploration for large deposits of low grade ore, Papua New Guinea law encouraged exploration by groups with men, money, management and expertise necessary for successful prosecution of such a search and such groups were already operating in the country.

Jan 1, 1990

By W. N. Brown

One of the seemingly eternal problems with which we are frequently faced is that of providing adequate and economical warehousing facilities to store large quantities of bulk product. Seasonal consumption, transportation, marketing, and other factors very often dictate extensive product warehousing requirements for an operation geared for steady, year-around production of a material requiring weather protection during storage. Fertilizers such as potash and urea are examples of such products; the consumption of these materials is extremely heavy in the early spring at which time the materials must be placed in the soil, whereas, for obvious operating efficiencies, production is more or less constant for a given operation throughout the year.

Jan 1, 1961

By David E. Nicholas

Design of underground openings is becoming more critical as the mine deposits become lower in grade, initial investments increase, ore depth increases, additional safety regulations come into law, and increased ore recovery is required for conservation of minerals. Stability of these openings is dependent on the strength of the rock mass and the pre-mine stress field. The rock mass is composed of solid blocks of rock (rock sub- stance) and structural features (faults, joints, bedding, etc.). Methods of testing the rock mass strength are improving and be- coming more common, however it is difficult to justify the high cost of large scale testing for an initial mine design. An alternative to testing the rock mass is to measure the rock substance and the structural features separately, and then combine them to estimate the rock mass strength. The rock mass strength will vary depending on the orientation of the opening with respect to the structural features. The other factor affecting the stability of underground open- ings is the pre-mine stress field. Methods are available to measure "directly" the pre-mine stress in competent and relatively massive rock. These methods are costly to employ, therefore, they may not be justified in an initial study. The pre-mine stress field can be estimated based on the structural relationships formed from past tectonic events.

Jan 1, 1976

By M. C. Roberts

The material composition of product is defined as the quantity of metal used per unit of product manufactured during a year. The material composition of product has shown steady and persistent declines over time for most metals and materials. This tendency demonstrates the continued improvements in manufacturing technology resulting from substitutions of other materials and increases in production efficiency. The purpose of this paper is to use the material composition of product to show the impact of advanced materials on the use of traditional metals.

Jan 1, 1992

By Dr. George W. Annadale, Dr. Adrian G. Chantler

Materials which are likely to produce Acid Rock Drainage (ARV) can be identified with a reasonable degree of certainty. However, it is not currently possible to predict the concentrations of future contaminant discharges with similar confidence. One way of overcoming this problem is to model the uncertainty in knowledge related to estimates of future contaminant concentrations, and utilize this information in a decision model to decide on acceptable levels of expenditure on ARV control measures. The paper presents a risk modeling approach and proposes a decision model.

Jan 1, 1992

By Irwan S. Halim

For tunnels in horizontally bedded rock, geologic factors affect the selection and design of the initial supports, including the rock propensity toward parting along bedding and the resulting high potential for rock slabbing during excavation. To evaluate this ground behavior, numerical analyses and results with Mohr-Coulomb, Hoek-Brown, and Ubiquitous Joint constitutive models were used, using the Upper Rouge CSO tunnel in Detroit, Michigan as an example. The different rock models and other geologic considerations are shown to impact the selection of the tunnel initial support and design. This paper emphasizes the appropriate selection of an analytical model based on the site specific geology to achieve an optimum initial support design.

Jan 1, 2008

By Robin J. Hickson

The Grasberg copper-gold deposit was discovered in the spring of 1988, one year before the planned closure of Freeport Indonesia&apos;s original Ertsberg openpit copper mine. In spite of Grasberg&apos;s remote location, 600 m (1968 ft) above the Ertsberg, atop a hitherto inaccessible mountain, Freeport-McMoRan brought its latest open-pit mine into production in the last week of 1989, less than two years after discovery. Freeport Indonesia&apos;s (FI) copper-gold mining operations are located in Irian Jaya, the easternmost province of Indonesia on the western side of the island of New Guinea. Fl&apos;s six ore deposits are all located within a 10- x 10-km&apos; (3.9- x 3.9-sq mile) Contract of Work area. They are all between the elevations of 2900 and 4300 m (9515 and 14,100 ft) above sea level, some 96 km (60 miles) from the island&apos;s southern coast. A 118-km (74-mile) access route connects FT&apos;s port site of Amamapare on the Arafura Sea to the project area. The first section is an 18-km (11-mile) barge waterway. The final 100-km (63mile) is a two-lane gravel highway. The highway terminates 9 km (5.5 miles) beyond the FI townsite at the project&apos;s central mill, some 2850 m (9250 ft) above sea level. The mining areas are separated from the mill by a 780-m (2560-ft) sheer cliff face. The world&apos;s longest free span tramway system, with a total length of more than 1.6 km (1 mile), is the only means of access for men and materials between the mill and the surface mines. Weight restrictions for the tramway for equipment considered for the project are 15.4 t (17 st). The minimum clear width dimension of two tunnels along the portsite access road is 5.6 m (18.4 ft).

Jan 1, 1991

By J. K. Ahlness

The US Bureau of Mines investigated technologies for determining the integrity of in situ leach mining wells. A self-contained trailer-mounted well integrity testing system (WITS) was designed and built to enable rapid testing of well casings for leaks as required by environmental regulations. The WITS utilizes two inflatable packers to seal off the entire casing length or any portion thereof. Water pressure is built between the packers to the desired test pressure, and the presence or absence of casing leaks is determined by monitoring the pressure drop between the packers. A winch and steel cable are used to run the packers in and out of the well. The WITS underwent an industry field test at the Irigaray in situ uranium leaching mine near Buffalo, WY. A total of 37 wells with an average depth of 69 m (225 ft) were tested at an average rate of four wells per eight-hour shift with a two-person operating crew. This represents a 75% time savings and an 83% labor savings compared to the rigid-pipe method previously used at the mine, with which a three-person crew tested an average of one well per shift.

Jan 1, 1988

By D. Duvris

Health and safety issues are a very important aspect of mining activities. Although the application of scientific research and current technology shields workers from many dangerous aspects of mining, accidents do happen. Many companies and institutions worldwide have committed to a continuous effort to minimize such occurrences. In this study, the health and safety data pertaining to the Greek mining and quarrying industry for the last 3 decades are presented and critically evaluated with respect to number of workers, annual production, etc. Appropriate indices are also calculated regarding the incidence and frequency of accidents. Health and safety issues specific to mining in Greek are also discussed.

Jan 1, 2000

By F. E. Heuze, R. N. Nilson, R. J. Shaffer, R. P. Swif

As part of the Unconventional Gas Program at the Lawrence Livermore National Laboratory, we are developing a model that allows for time-dependent tracking of the fluid front and flow pressures during the quasi-static or dynamic fracturing of jointed rocks. Application of the model is directed towards both short fast fractures (as in tailored pulse loading) and long hydraulically induced fractures (massive hydraulic fracturing). The thrust of this research is to determine crack extension characteristics due to specific joint systems and fluid properties and to correlate pumping records with crack behavior in jointed systems.

Jan 1, 1986

By W. E. Horst

Historically, research organizations have made significant contributions to the development and commercialization of new chemical products for the mining industry and examples of commercial results are cited With the recent demise of research organizations within the mining industry and dynamic changes in the industry, the supporting role of R&D groups has become limited or non-existent. Cat- reduction requirements and new raw-material sources offer future opportunities for R&D organizations to continue their effective participation in the commerical development of new chemical products. Potential areas of interest for future process applications are reviewed.

Jan 1, 1986

By C. G. Treworgy

Geologists at the Illinois State Geological Survey are evaluating geologic and land use conditions that affect the minability of coal to determine how much coal is available for development using current technology and mining practices. Coal resources are being evaluated for selected 7.5-minute quadrangle study areas. In a central Illinois study area, more than 25% of the deep-minable resources were limited from development by unstable roof conditions resulting from thick unconsolidated sediments overlying thin bedrock overburden. In some southern and southeastern Illinois study areas, geologic conditions associated with a paleo-channel limit the minability of significant resources of low-to medium-sulfur coal. Some features which were thought to limit mining, such as areas of closely-spaced oil wells, have been found to have minimal impact on the amount of coal recovered.

Jan 1, 1995

By D. Nutakor

Rock joint stiffness is not only a poorly known parameter, but also has no established laboratory measurement procedure. This paper presents methods used to determine the normal and shear stiffnesses of healed joints filled with vapor-altered minerals obtained from the Yucca Mountain site in Nevada. Results show that these joints behave linearly up to 85% of their loading history and are stiff with strengths very close to the strength of the intact rock. Factors that might have contributed to the linear behavior of these joints are discussed and areas requiring further investigation are provided. Joint normal stiffness ranges from 7.16 to 64.77 GPa/mm with an average value of 26.93 GPa/mm, while joint shear stiffness averages 11.41 GPa/mm and ranges from 3.09 to 28.41 GPa/mm. Young?s modulus of the vapor-altered joint infilling was calculated from the stiffness of the healed joint. Young?s modulus of the vapor-altered joint filling material averages 7.89 GPa and ranges from 2.15 to 19.43 GPa. Given the pervasive presence of such altered rock, usually in the form of sub-spheroidal 3-D pockets, this property should be of value in any numerical modeling attempting to describe the mechanical behavior of these tuff formations at the level of detail where inclusions might be a factor.

Jan 1, 2008

By Gregory M. Rumbaugh, Todd Kostecki, Christopher Mark

From 2015 to 2021, five massive pillar collapses occurred at four underground stone mines in the eastern United States. These events resulted in powerful airblasts that damaged mine infrastructure and mobile equipment, seriously injured miners, and disrupted underground travelways. Each of these pillar collapses propagated through the overlying strata, causing a subsidence basin on the surface. Pillar collapses are particularly hazardous for miners because they can occur with little warning and can affect miners that are far from the pillar collapse area. The following case studies show that certain factors may increase the likelihood of a pillar collapse. For instance, each of the five events involved the collapse of at least twelve benched pillars with width-to-height ratios (w/h) of 0.8 or less. This study elaborates on

By C. L. Pillar

In many cases, substantial time may elapse between the exploration stage and a serious detailed planning stage which has the objective of putting a mineral property into production. This is always true where properties change ownership and new partners are brought in for joint venture situations. Such conditions make it imperative that the recording of complete and accurate geological data for the property is done during the active part of the exploration phase and accomplished by competent geologists and engineers. This work should not be left to helpers and technicians. Furthermore, it should not have to be redone years after the actual drilling was accomplished, when either those involved have parted company or those present have lost the touch and feel of their part of the exploration program and must rely on a memory sketchy in detail, at the best. All of this emphasizes the importance of thorough geological evaluation and reporting during the exploration program. To evaluate and comment on the application of geological data by a mine planning department, we must assume (1) that sufficient diamond drill holes have outlined the existence of a potentially economic ore deposit, and (2) that the next step is to obtain the required information to allow a detailed feasibility study. This paper will comment on: 1. what types of geological information are required, 2. how it can be obtained, and 3. comments on the application of this information by the mine planners.

Jan 1, 1973

By J. G. Pippenger

The mining industry has been Australia?s major economic driver over the past decade, contributing 8% to Australia?s Gross Domestic Product and 26% of Australian Stock Exchange Market capitalisation. Australia is the world&apos;s leading exporter in coal, iron ore, alumina, lead and zinc; and second largest in gold and uranium. While driving the economy, this resource boom has also created a demand for professional and operating talent that has far outstripped the capacity of Australia?s 21 million residents. I moved to Australia some 10 years ago and have not looked back. This unique island continent with its mix of Indigenous and diverse immigrants ? many still proud of their convict ancestry ? has offered life long memories both professionally and personally.

Jan 1, 2011

By SAMUEL A. LOLON, ADITYA JUGANDA, JURGEN F. BRUNE, JR. GREGORY E. BOGIN

Historically, there have been many events of mine fires and explosions recorded in the United States and other countries that have demonstrated the existence of explosive methane-air mixtures, herein referred to as explosive gas zones (EGZs) [1]. The risk of mine explosions can increase if these EGZs migrate out from the gob into the surrounding mine entries — a phenomenon known as gob breathing. A number of 3D computational fluid dynamics (CFD) simulations using various magnitudes and periods of barometric pressure variation have indicated that the EGZ outgassing potentially occurs due to lags in pressure, which are strongly influenced by mine conditions and ventilation systems. Early-warning systems with real-time pressure monitoring and the application of gob ventilation boreholes are recommended to detect and mitigate explosion hazards from gob outgassing.

A portable electronic instrument was developed which will measure change of longitudinal wave velocity with change of uniaxial stress in rock columns. The instrument is a solid-state device powered by nickel-cadmium batteries. It uses a probe of two piezo-electric crystals spaced inches apart to send and receive a pulse through a stressed rock. A one-inch cathode ray oscilloscope visually displays the longitudinal wave. A reference chart is used to find the stress. Laboratory results have indicated that the average stress on a sandstone column can be found to within 35 psi. The feasibility of using this instrument to determine stresses in mine pillars is to be studied. The instrument may be used to investigate physical properties of rock.

Jan 1, 1970

By Ronald S. Tanaka

In the planning stages for a dozen years, the 9.11 mile long Mount Macdonald Tunnel is the focal point of the $600 million dollar Rogers Pass Project. The paper will discuss the construction of the tunnel that is being carried out from both ends. The eastern portion contractor has used a tunnel boring machine to excavate the upper part of the tunnel and at the west end contractor selected the conventional drill and blast method. A ventilation shaft located near the mid point is the main part of a ventilation system unique in the Western Hemisphere.

Jan 1, 1987