Search Documents

If it had not been for the almost unbelievable adventures that came before and after, the last ten months of 19 15 would have been exciting enough for anyone. As it was they were a cheerful interlude. I spent most of the time on our Warren operations catching up on a lot of underground work and visiting Ajo every few weeks to see if my Chuquicamata visit might help solve the New Cornelia problem. While the difficulties were finally solved, at times they seemed almost hopeless. About all I could do to help was to make sure that the ore sent to the pilot plants represented the average ore that must be treated in the final 5000 tpd mill. Dr. Ricketts and John Greenway worked tirelessly with the best consulting advice they could obtain. Credit for the final success was due chiefly to their efforts. Since our old group had given up its "Merry Widow" home in Warren, a few of us got rooms in the company-built Cole Building over the Warren grocery store. This included Jim Lewis, Roy Mitchell, Steve Landon, Paul Stevens, and Hubert d'Autremont who came from Duluth to join our legal staff. Later we rented a small house two blocks from the Calumet and Arizona office. With the now flourishing country club only a 10-min walk away, and an electric car running to it every half hour or so, we were able to give parties in return for the hospitality of our friends. One of the most pleasant episodes came by luck a few days after I got back from Chile. Chester Congdon, a leading director in Calumet and Arizona, with his wife and their daughters, Elizabeth and Helen, spent a couple of days at the Greenway house before making an auto- mobile trip across the desert from Tucson to Ajo. At the same time I arranged to examine the small but rich Bush and Baxter copper mine a few miles from Tucson. At a party in Warren we found we would all be staying at the Santa Rita Hotel in Tucson, and I took my South

Jan 1, 1976

By Frank H. Madison

The percentage depletion deduction on Federal Income Tax Returns under the provisions of the 1939 Internal Revenue Code and of Sections 611 to Section 615, inclusive, of the revenue act of 1954, have created innumerable administrative difficulties, and a new interpretation of "gross income from the property" in that the Courts have expanded the ideas of what constitutes "gross income from the property" to a degree unheard of and unthought of prior to the enactment of these two codes. Originally, under the Revenue Acts of 1917, 1918, and 1920 depletion was allowable, based upon mine valuations as of March 1, 1913; if the mine was owned prior to March 1, 1913; upon cost, as of the date of acquisition if purchased subsequent to March 1, 1913; and upon a "discovery" basis if the mine was discovered after March 1, 1913, The "jab" for mine valuations as of March 1, 1913 and for discovery valuations and depletion was not as bad as it has been made out to be. Thousands of valuations and estimates of reserves were made and agreed upon between taxpayers and Internal Revenue Service engineers and as the years went on the answers have been found to be "reasonable." However, human nature being what it is each case was a battle of wits - of a sort - and many resulted in severe differences of opinion and litigation. As tax rates increased the situation was not bettered. I could talk for several hours on this phase of depletion but it is all past now andwould not give any real service or better understanding of the matter.

Jan 1, 1958

By J. W. Hawkins, K. B. C. Brady, K. Miller, J. Cuddeback

Remining of abandoned coal mines in Pennsylvania requires the implementation of pollution abatement and mining techniques called Best Management Practices (BMPs). Water-quality data from over 100 remining sites with more than 230 abandoned discharges were analyzed with respect to the types of BMPs employed to abate the pollution loadings of acidity, iron, manganese, aluminum and sulfate. Discharges exhibiting a significant decrease in acidity were most highly associated with sites where large volumes of alkaline materials were encountered (66.7%) or added (63.7%). The best results for iron loading were achieved with large-quantity alkaline addition (54.6%) and water handling systems (47.8%). Water handling systems (47.4%), daylighting (40.7%), and revegetation (40.2%) were associated with significantly lower manganese loadings. The decreases in acidity and sulfate loads associated with increasing the amount of alkaline material in the backfill indicates that the production of acid mine drainage can be retarded by adding large quantities of alkaline materials.

Jan 1, 2002

By R. Heersink, C. H. Wells

Innovations in communications and real-time information systems are providing industry opportunities to improve profitability. Real-time operating data is collected from equipment across a site or even several sites into a central server for secure PC and PDA-based Internet access. This paper includes discussion of how operating staff can use wireless devices to see equipment and processing data from anywhere throughout the mines and concentrators, and how management can view results from multiple mines, all in real time. Additional opportunities enabled through the remote access by equipment vendors or mining consultants is also presented, as well as an overview of typical benefits and current installations.

Jan 1, 2002

By Y. Luo

In designing and operating underground room-and-pillar coal mines, it is always difficult to achieve a good balance between preventing surface subsidence and achieving high recovery ratio. In this paper, a design methodology applying the pressure arch theory is proposed, and the principles and mathematical models involved are detailed. A computer program was developed to carry out the design optimization process and was applied to the examination of a documented case in which a massive cascading pillar failure had occurred over a large area in a shallow coal mine. The results indicate that the proposed design method can be applied to prevent subsidence while achieving reasonably high recovery ratio for roomand- pillar mining operations.

Jan 1, 2014

By Russel Delmar

Construction of Ontario Power Generation?s 12.8-m diameter, 10.4-km long water diversion tunnel in Niagara Falls, Ontario, is underway. The tunnel is being excavated by means of a 14.44-m diameter open gripper Tunnel Boring Machine. The tunnel lining is constructed as a two-pass system with the initial lining consisting of rock bolts, mesh, steel channels or ribs, and shotcrete, and the final lining consisting of pre-stressed cast-in-place concrete with a waterproof membrane. This paper describes salient design and construction aspects as follows: ? Regional and Site Geology ? Tunnel Layout and Design ? TBM Tunnelling and Cast-in-place Concrete Lining Construction

Jan 1, 2008

By · J. B. Boisvert, O. Leuangthong, T. Acorn

Optimizing final pit limits for stochastic models provides access to geologic and economic uncertainty in the pit optimization stages of a mining project. This paper presents an approach for optimizing final pit limits for a highly variable and geologically complex gold deposit. A heuristic pit optimizer is used to manage the effect of geological uncertainty in the resources within a pit shell with multiple uncertainty rated solutions. The uncertainty rated pit shells follow the meanvariance criterion to approximate the efficient frontier for final pit limits. Stochastic dominance rules are then used in a risk management framework to further eliminate sub-optimal solutions along the efficient frontier. This results in a smaller set of final pit shells that could be further analyzed for production scheduling. Additionally, the original solutions are analyzed for changes in the mining limits and two regions are targeted as potential regions for further exploration.

By · J. B. Boisvert, O. Leuangthong, T. Acorn

Optimizing final pit limits for stochastic models provides access to geologic and economic uncertainty in the pit optimization stages of a mining project. This paper presents an approach for optimizing final pit limits for a highly variable and geologically complex gold deposit. A heuristic pit optimizer is used to manage the effect of geological uncertainty in the resources within a pit shell with multiple uncertainty rated solutions. The uncertainty rated pit shells follow the meanvariance criterion to approximate the efficient frontier for final pit limits. Stochastic dominance rules are then used in a risk management framework to further eliminate sub-optimal solutions along the efficient frontier. This results in a smaller set of final pit shells that could be further analyzed for production scheduling. Additionally, the original solutions are analyzed for changes in the mining limits and two regions are targeted as potential regions for further exploration.

By G. Mike Bernard

The Andacollo gold mine is located near the town of Andacollo (population 14,000 people) in Chile’s region four. It is about 56km (35 miles) by paved road from the coastal city of La Serena. Santiago is about480 km (300 miles) south. Site elevation varies between 1,000 and 1,280 m(3,300 and 4,200 ft). The climate at the Andacollo site is moderate but arid. Average annual rainfall is only 130mm (5 in.). Because there is little rain and the temperature varies only a few degrees (14 to 24 C or 57 to 75F), there are no problems with freezing, solution dilution or pad saturation. The climatic conditions are ideal for heap leaching.

Jan 1, 1996

By Y. Luo

Cuando se diseña y operan minas de carbón subterráneas con el método de cámaras y pilares, es siempre difícil obtener un buen equilibrio entre la prevención de subsidencia de la superficie y la obtención de un alto coeficiente de recuperación. En este trabajo se propone una metodología de diseño aplicando la teoría de arco de presión y se detallan los principios y modelos matemáticos involucrados. Se desarrolló un programa de computadora a fin de realizar el proceso de optimización del diseño y fue aplicado a la examinación de un caso documentado en el que había sucedido una falla masiva de un pilar en cascada sobre un área grande en una mina de carbón poco profunda. Los resultados indican que el método de diseño propuesto puede ser aplicado para prevenir la subsidencia y a la vez obtener un alto coeficiente de recuperación para operaciones mineras de cámara y pilares.

Jan 1, 2014

By Raymond W. Henn, Kent A. Pease, Glen J. Rorison

The paper focuses on construction of a 2.55-km (8,365-ft) long, 2.4-m (8-ft)diameter storm drain tunnel in Evansville, Indiana. The tunnel was driven through saturated soft ground varying from clay to fine sand. The paper presents: an overview of design and design rational including specific EPB machine requirements; the contractor’s proposed and accepted alternative construction methods and TBM design; and construction issues and performance. Some of the key points discussed are the use of the TBM in different operational modes for alternative ground conditions, the effectiveness of dewatering systems, production rates, and issues such as surface settlements and gas.

Jan 1, 2001

By E. McCullough, S. Gaillard

"Diesel particulate matter (DPM) has been regulated by the U.S. Mine Safety and Health Administration since 2002 in underground metal and nonmetal mines. To demonstrate regulatory compliance, DPM samples must be collected and later analyzed by the U.S. National Institute for Occupational Safety and Health (NIOSH) 5040 standard method, but the FLIR Airtec DPM monitor can serve as a complementary engineering tool. The monitor is a handheld instrument that offers near-real-time measurements of elemental carbon (EC), which is a primary constituent of DPM. As part of an ongoing field study, the monitor was used to survey EC in an underground stone mine. This effort was aimed at determining spatial and temporal DPM variations in several key locations. The results of prolonged area monitoring—that is, lasting several hours — revealed that DPM concentrations were diluted substantially as air moved away from the primary production zone, but that concentrations could vary quite a bit in a single location from day to day and between seasons. DPM concentrations were generally lower in winter than in summer, which is consistent with increased natural ventilation airflows during winter. Using a modified sampling cassette, an attempt was also made to sensitize the Airtec monitor to allow for “spot-checking” of EC concentrations — that is, measurements made in several minutes. Preliminary field data showed that the sensitive cassette performed well in terms of providing accurate data that could be useful for rapid assessment of DPM. IntroductionDiesel particulate matter (DPM) is the solid fraction of the exhaust emissions from a diesel engine. It largely consists of elemental carbon (EC) and organic carbon (OC) (Birch, 2003). The World Health Organization International Agency for Research on Cancer classified diesel exhaust, including DPM, as a carcinogen (World Health Organization, 2012). It is believed to cause and/or exacerbate respiratory illness upon inhalation, deposition and retention in lung tissue. Because DPM exists in both the micro- and nanoparticulate ranges, it can bypass typical autoimmune defense mechanisms that keep larger particles out of the respiratory system (Ristovski et al., 2012)."

Dec 1, 2016

By M. SIDDARAJU, Rameshwar Sah, Satendra Kumar, Arvind Jaiswal

The study explores a novel process to sinter porous iron ore with improved productivity and quality. The iron ore is pre-processed with calcined lime to temporarily close pores, preventing water absorption during granulation. This enhances reaction kinetics and early slag formation during sintering, resulting in significant improvements in sinter productivity, product yield, and cold strength property.

Feb 28, 2022

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

Energy dissipation and fragmentation of rock is of interest for mine-to-mill operations in order to understand breakage and to minimize energy consumption during blasting at the mine site, and comminution at the processing plant. In this regard, high velocity impact breakage of long granite cores, called bars, has been studied with instrumented strain gages to follow the energy dissipation gradient along the bar length resulting from the strain waves generated by impact. As a result of high velocity impact, three zones have been identified (fragmentation, fracture, and elastic) and these three zones have been characterized in 3D using X-ray tomography. The fragmentation zones of the granite bars were studied in detail to describe the particle size distribution and the particle shape characteristics. Finally, the experimental energy dissipation for the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work equation, if the anisotropic granite particles are defined by length rather than by sieve size.

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

Energy dissipation and fragmentation of rock is of interest for mine-to-mill operations in order to understand breakage and to minimize energy consumption during blasting at the mine site, and comminution at the processing plant. In this regard, high velocity impact breakage of long granite cores, called bars, has been studied with instrumented strain gages to follow the energy dissipation gradient along the bar length resulting from the strain waves generated by impact. As a result of high velocity impact, three zones have been identified (fragmentation, fracture, and elastic) and these three zones have been characterized in 3D using X-ray tomography. The fragmentation zones of the granite bars were studied in detail to describe the particle size distribution and the particle shape characteristics. Finally, the experimental energy dissipation for the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work equation, if the anisotropic granite particles are defined by length rather than by sieve size.

By W. G. Pariseau

This contribution describes rock mechanics features of the Davis Cavern at the former Homestake Mine in Lead, South Dakota, U.S.A. The mine is located in the northern Black Hills of South Dakota. In 2003 and again in 2008, the mine site was recommended for development as a national Deep Underground Science and Engineering Laboratory (DUSEL) in cooperation with the Sanford Underground Science and Engineering Laboratory under the South Dakota Science and Technology Authority (SDSTA). The original Davis Cavern was excavated about 9.1x16.8x9.7 m high (30x55x32 ft high) in 1965 (Mitchell 2009) at a depth of 1,478 m (4850 ft). The purpose of the cavern was to house apparatus for detecting solar neutrinos. The experiment ultimately proved successful and earned R. Davis a share of the 2002 Nobel Prize in physics. Recently, a new experiment (LUX=Large Underground Xenon detector for dark matter particles and WIMP's=weakly interacting massive particles) was proposed for the Davis Cavern that required an increase in height of 2.4 m (8 ft). For many years, the Homestake gold mine was the deepest operating mine in North America. Development extended to the 8000 Level (2,438 m). The mine closed in 2003. Pumps were shut off and the water level rose to the 4350 Level, about 150 m (500 ft) above the Davis Cavern. Some six years later after selection for DUSEL proposal development by the National Science Foundation (NSF), access to the 4850 Level and the Davis Cavern was regained. Pumping has lowered the water level to well below the cavern floor. Figure 1 shows the layout and location of the Davis Cavern (Cavity). Detector tank, supporting steel, and so forth were subsequently removed. The cavern was re-supported and new access was developed. By August, 2010, 13,000 ft3 had been removed during enlargement and renovation of the Davis Cavern. Figure 2 shows the detector tank under construction in 1965.

Jan 1, 2012

By R. J. Hickson

The Grasberg copper-gold deposit was discovered in Spring 1988, just one year prior to the planned closure of Freeport Indonesia's original Ertsberg open pit copper mine. In spite of Grasberg's remote location, 600m above the Ertsberg, atop a hitherto inaccessible mountain, Freeport-McMoRan brought their latest open pit mine into production in the last week of 1989, less than two years after discovery. This paper describes the start-up of the operation, highlighting synergies drawn from both the original Ertsberg experiences and the current Freeport Indonesia underground mines.

Jan 1, 1991

By John D. Morton, J. H. LaVerne Palmer, Douglas J. Belshaw

An extensive programme of ground instrumentation and observation was carried out for the West Duff in Outfall Sewer tunnel project prior to and during construction, to establish the performance characteristics of the rock through which the tunnel and appurtenant openings were dug and to examine the nature of the lining-to-ground interaction. The existence of high horizontal residual ground stresses was confirmed, and values established by overcoring. Rock deformations and stress changes were monitored during tunnelling. Permanent stress and strain monitoring devices were set into the final lining and these are continuing to operate. INTRODUCTION The site is located on the north shore of Lake Ontario at Pickering, some 20 miles (32 kilometres) east of Toronto, Canada where a variable thickness of glacial or interglacial sediments overlies bituminous shale bedrock of. the Collingwood Formation which is lower Ordovician age. Approximately 50 feet (15 metres) of glacial cover exists at the shaft, though this thins abruptly at the regressing cliffed shoreline such that several small areas of exposed bedrock exist in the lakebed. The general location, overall geological section and detailed site plan and profile are illustrated in Figs.1,2 and 3 respectively. General properties of the rock as established during an extensive test drilling and site investigation programme are listed in Table 1, while stress determination by USER overcoring stress meter device are given in Table ll. These data formed the basis of analyses which were done to examine the intended outfall design, and to detail the construction procedure and the observational instrumentation programme.

Jan 1, 1979

By Paloma Lazaro, Moe Momayez

Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body’s response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body’s response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.

By Paloma Lazaro, Moe Momayez

Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body’s response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body’s response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.