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By B. McNulty

The Niblack polymetallic volcanogenic massive sulfide deposits are located on Prince of Wales Island in southeast Alaska, approximately 50 km southwest of Ketchikan. The property hosts a number of polymetallic volcanogenic sulfide occurrences within the folded Lookout rhyolite volcanic succession. The Lookout deposit is the primary focus of current resource delineation and contains an indicated resource of 4,136,000 tonnes at 1.13% Cu, 2.32 g/t Au, 2.27% Zn, 38.70 g/t Ag and an inferred resource of 1,736,000 tonnes at 1.09% Cu, 1.77 g/t Au, 2.02% Zn, and 25.52 g/t Ag as of March 2011. Sulfide mineralization is interpreted to have formed sub-seafloor, within permeable felsic fragmental volcanic rocks. Sulfide minerals of economic interest include chalcopyrite and Fe-poor, Zn-rich sphalerite. Of considerable importance, the Lookout deposit contains elevated gold that occurs as inclusions within the base metal sulfides.

Jan 1, 2012

By John A. Breslin

The year 2010 will mark the 100th anniversary of the beginning of the research efforts by the U.S. government to improve the health and safety of miners working in the United States. This research began in 1910 with the establishment of the U.S. Bureau of Mines (the Bureau) and it has continued during the past 10 decades, even after the closure of the Bureau in 1996. The research on safer mining technology, formerly done by the Bureau, has now been combined with National Institute for Occupational Safety and Health (NIOSH) studies of miners? health to form a unified federal research program to improve the health and safety of miners. This article describes this research and places some of the accomplishments into perspective with other activities in the U.S. Mine Safety and Health Time Line (insert).

Jan 1, 2010

By C. Bazin

Grinding circuits are operated in the presence of disturbances due to ore changes and equipment malfunctions. One of the challenges faced by the operators is the detection of a disturbance, the identification of its origin and of the action to correct the problem. Hydrocyclones overloading, worn or partly plugged apexes of the units of a nest, surging and internal liner detachment may cause a loss of classification capacity and quality leading to a less efficient grinding operation. A dynamic simulator is used to assess rules for the diagnosis of hydrocyclone faults from the trends produced by sensors.

Jan 1, 2009

By Steve Kral

MINExpo INTERNATIONL 2000 was a good place for companies to introduce new products, technologies and services to the mining industry. Caterpillar took that a step further. The company hosted a one-day preview of its mining products at its Tinaja Hills Training and Demonstration Center near Tucson, AZ. About 30 members of the trade press spent the day at Tinaja Hills before heading on to Las Vegas for MINExpo INTERNATIONAL 2000. Dozens of Caterpillar professionals provided the editors with a first-hand look at Caterpillar’s mining trucks, loaders, excavators, road graders, water trucks and engines. In addition, these Cat experts explained the intricacies of each piece of equipment, the latest technology that led their improvement and their value to the company’s mining customers.

Jan 1, 2000

By Keith Schaeffer

This paper presents a history of the planning, engineering and construction completed for the railroad tunnel crossing part of the West Elizabeth Avenue Storm Drainage Project, undertaken to relieve flooding within the West Elizabeth Avenue area in Linden, NJ. The Railroad Crossing Contract is part of the larger Linden Drainage Improvements Project consisting of a new gravity storm sewer system. The improvements are required to provide additional storm drainage for the City of Linden and the Merck Pharmaceuticals manufacturing facilities in the City of Linden.

Jan 1, 2008

By V. L. Franzen, Z. J. Hladysz, C. A. Kliche

The Wharf Resources mine, located in the Bald Mountain Mining District approximately 6.4 km (4miles) west of Lead, South Dakota, has operated a surface gold and silver mine and heap leaching processing facility since 1983. Wharf Resources intends to mine and process gold and silver ore from the Wharf Expansion area which is located on the eastern flank of the currently permitted Foley Ridge Mine. The Trojan Pit for the Wharf Expansion area was initially designed with an overall highwall slope angle of 45o. During mine permit presubmission meetings with personnel from the SD Department of Environment and Natural Resources (SD DENR), the question arose as to whether a detailed slope stability analysis of the proposed Trojan Pit highwalls was completed to justify the 45o slope. Wharf’s response was that the highwall design was based, in part, upon studies completed in1987 on the Annie Creek and Foley Ridge Mines; and, in part, upon subsequent slope stability analyses conducted by Wharf mine personnel through 1996. It was suggested by the SD DENR that the stability study be updated to reflect structural geological conditions in the Wharf Expansion area.

Jan 1, 2000

By B. A. Ridolfi, S. M. Alvarez

The Moon Creek Reclamation Project provides a case study in the development of creative cleanup solutions for an abandoned lead and zinc mine and mill site located in northern Idaho. Innovative design features include construction of a 88,000cubic yard combined waste containment facility on soft in-situ tailings, water-balance cap, limestone gravel drains, a geocell mattress for stability, and a below-grade scour protection berm. The stream, including a wetlands buffer, will be relocated within an existing road alignment and rehabilitated to provide trout habitat. These elements allow for the integration of reclamation and stabilization measures into an effective site design.

Jan 1, 1999

By F. -J. Wodopia

Sustainability of energy supplies has been an issue of general interest for a long time. Whilst in the past the continuous productive use of natural commodities was in the fore, its compatibility with the environment and climate and ultimately also social aspects have recently gained more and more attention. Today many discussions focus on the climate compatibility of individual options to act. Fossil fuels, in particular coal and lignite, are generally challenged because coal use makes a significant contribution to global man-made CO2 emissions. The drastic increase in the consumption of fossil fuels is not explained by the fact that coal utilisation technologies are not or cannot be sustainable but rather by the growing world population and the endeavours numerous national economies trying to catch up economically. Coal is the world’s No. 1 fuel and, in the view of many experts, will keep this position also in the foreseeable future. The access to its deposits plays a significant role for the economies of the emerging countries. Consequently the aspects of energy security and economic efficiency need to be considered at eye level with climate compatibility. In Germany, however, the public acceptance of fossil fuels and of large industrial projects is in the focus of attention.

Jan 1, 2011

By M. K. Larson, R. G. Wade

Researchers at the National Institute for Occupational Safety and Health (NIOSH) are studying the time-dependent response of rock stressed along weakness planes. The objective is to improve mine safety by reducing the number of roof falls that cause injuries and fatalities to miners. Researchers conducted direct-shear tests on mud-stoneovercored from a coal mine roof. Results showed frictional strength weakens with displacement along the shearing planes. Results of direct-shear creep tests also showed time-dependent deformation. Test measurements were compared to classical analytical models. Results suggest that risk of roof collapse may be decreased through layout and support design to reduce creep rates and thus slow progression toward failure.

Jan 1, 2000

By O. Konovalov, M. Zhuravkov

In report the results of performance of research works on building up of the connected geoecological and geomechanical monitoring system for modelling and study of a state of mining massif in a region with large-scale underground mining works are discussed. The connected geoecological monitoring requires radical change of methodology of carried out works. To carry out modelling and researches it is impossible without construction of the integrated connected information model of region. Basis of construction of information systems and databases for all sections of Earth Sciences is the set of the approaches, among which, for example, methods of remote sounding, GIS- and GPS-technology etc. Computer technologies are basis on the "supercomputer" technology. The results of performance of some researches for regions of excavation of deposits of potash salts in Russia and Belarus are presented.

Jan 1, 2005

By Charlie Watts, Ken Smales, Ron Fleming

The Manapouri Power Station is an underground hydro-electric station located in the South Island of New Zealand, and was constructed in the 1960s. Between 1997and 2002, a second 10m diameter tailrace tunnel was constructed to increase the out-put and to improve the overall hydraulic efficiency and output of the station. A critical economic and project approval consideration for the second tunnel was the outage time required for the breakthrough into the power station. The power station is in part dedicated to providing power to an aluminum smelter with the balance to the National Grid, and apart from the physical problems associated with providing an alter-native power supply to the smelter, the loss of generation revenue and supply risk were significant issues. Innovative planning reduced the planned outage time from several months to21 days, and the breakthrough was eventually achieved in 11 days as a result of additional value engineering measures implemented during construction. This paper describes the engineering optimization that took place during the planning stages of the project and later during construction, as well as describing the construction methodology used.

Jan 1, 2007

By S. Rupprecht

"This article addresses the prevalence of poor public reporting practices of coal exploration results, coal resources and coal reserves in southern Africa. Currently, the reporting of coal tonnage without supporting coal qualities or saleable tonnes and quality is a poor reporting practice that occurs far too often. Not all coal is equal — therefore it is extremely important that investors or potential investors are provided with the full details of both run-of-mine (ROM) and saleable coal tonnage, their associated qualities and other material and relevant information.Competent or qualified persons should note that publicly reported information should be sufficient to enable an informed reader to make a reasonable and balanced assessment of the significance of the information provided. “Companies are encouraged to provide information in their public reports, which is as comprehensive as possible (CRIRSCO, 2013).” However, too often this isn’t the case, and material matters are either not reported or inadequately disclosed.According to the South African National Standard (SANS) 10320:2014 draft document, “tonnage and coal quality that will be available for sale, either in the raw ROM state (raw saleable) at a specified moisture content, or after beneficiation of the ROM coal by processing operations to produce materials at specified qualities, size ranges and moisture contents. The assessments must demonstrate that at the time of reporting, the marketing of the products is reasonably justified. The basis of the predicted practical product yield to achieve the saleable coal reserve must be stated. The moisture basis of reporting shall be stated.” An example as to why coal qualities are so important to the public, the requirements of South Africa’s electric public utility (Eskom) power stations are detailed in the followint paragraphs. The Kendal power station, commissioned in 1988, operates at a calorific value (CV) range of 19 to 20 MJ/ kg, an ash content between 29 and 34 percent and volatiles between 20 to 21 percent. Other power stations, such as Kriel or Hendrina, may require different qualities, such as a CV range of 22 to 23 MJ/kg, an ash content between 20 and 28 percent and volatiles between 22 to 23 percent. Thus, in terms of domestic saleable coal, it is not just about reporting the coal qualities but also informing the investor as to which power station the coal is intended to be sold as “boilers are designed to burn particular qualities of coal” and “it is not always possible to transfer coal between stations because of different quality requirements at each station (Chetty, 2010).” Sulfur content is another important quality with the ideal coal content having a quality of less than 1 percent sulfur."

Jul 1, 2019

By Jai Ghosh, Aprad E. Torma, Roger Guay

The catalytic effect of ferrous ion in the industrial biohydrometallurgical heap and dump leaching processes is explained. During the bacterial leaching of metal sulfides, ferric ion will partly be hydrolyzed and a variety of sols, gels, amorphous and/ or crystalline mono- and polynuc- lear hydroxo- and sulfato complex species formed, especially by olation and aggregation reactions. There are many problems associated with these iron precipitates especially in the purification of leach solutions. The present study will discuss the iron precipitation reactions; gives kinetic and thermodynamic evaluations of the effect of temperature on pyrite and ferrous iron oxidation; and reports on the tolerance of heavy metal ion concentrations by Thiobacillus ferrooxidans.

Jan 1, 1989

By M. Moagabo

CO2 emissions from carbonate laden reclaimed mine spoil has been shown to pose a hazard to residents in homes built on or adjacent to such land. The objective of this project was to develop a soil CO2 flux survey protocol for assessing reclaimed mine land. The research involved CO2 chamber accumulation flux surveys; stable carbon isotope ratio analysis; statistical hypothesis testing to examine correlation between CO2 flux and soil temperature and moisture as well as spatial dependence; and geostatistics to map CO2 and delineate high flux zones. Soil temperature was observed to have a positive correlation with fluxes while soil moisture was observed to be negatively correlated. Spatial dependence of CO2 fluxes on reclaimed mine land was observed on one of the two study sites. The research suggests that macro-porosity and gas permeability may be important factors that explain CO2 migration in mine spoil. A flux survey protocol has been developed, based on these results, for reclaimed mine lands. The work demonstrates the capability of geostatistical methods to delineate high flux fields. Further research will be required to determine suitable thresholds for such analysis.

Jan 1, 2012

By Douglas B. Silver

Super Cycle future The final topic is mining?s future. The most important questions are ?How much longer is the Super Cycle going to last? What should we expect to see going forward? How will the Super Cycle end?? Three possible scenarios follow. Scenario one: Super Cycle has peaked Kathy Casey-Kirschling is officially the first Baby Boomer. She was born Jan. 1st, 1946. If you google ?first baby boomer,? she?s the one that shows up. A Baby Boomer is anybody born between 1946 and 1964. In the United States, it represents about a quarter of the population ? approximately 76 million people. The Baby Boomer generation is going to change the economics of the world because there are so many in the generation. A review of spending patterns indicates that the largest amount of discretionary spending occurs between the ages of 49 and 52. Retired people tend to live on fixed incomes so they have less discretionary income. They also tend to downsize their house, which may contribute to the housing glut and the need for a lot less metal. Therefore, the upcoming retirement of the Baby Boomer generation could result in a massive shift in economic spending resulting in the peaking of the Super Cycle. Figure 1 is an index graph from the Toronto Stock Exchange (TSX). The index has recently peaked. A lot of people see that as a sign that bad things coming our way. A careful review of different commodity prices also suggest that the peak has occurred and it does not seem to matter which commodity prices are considered. Copper prices have seen a peak as have nickel prices. Nickel and molybdenum displayed the same trend with a peak in 2005 as did zinc. Uranium, which has single-handedly tried to behave like the dot com craze, has also peaked.

Jan 1, 2008

By Kevin Andrews, Terry Hamric, Scott Nelson

"Mining conditions in underground coal mines are dictated by the environment in which the coal seams were geologically deposited. Depositional features can change rapidly, significantly affecting mining conditions. Mine geologists understand factors affecting mining conditions, predict future conditions, and provide guidance to mine management. A case study demonstrates how a mine in Appalachia merged an understanding of depositional environments with mining conditions and drilling data to make informed decisions as the mine encountered geologic anomalies. The assessment included drilling, mapping of geologic hazards and mine productivity, and creation of a conceptual depositional model. Metallurgical coal quality and clean tons per foot served as incentives for continued advance. Mining in the south was historically favorable, with good production and advance rates. As mining advanced north, changing geologic conditions caused the upper seam split to abruptly disappear. The mine ramped down into the lower seam split. Mining in the north area encountered unfavorable conditions, including transition roof, “horsebacks,” sandstone intrusions, roof rolls, and bony floor, resulting in low rates of mining advance. The mine geologist characterized the features and created a predictive model for future mining. Most of the adverse conditions were attributed to the coal in the north being part of an incised, transgressive valley fill environment, as compared to the favorable conditions in the south resulting from a floodplain depositional environment. Geologic conditions, low productivity, and unfavorable future predicted conditions in the north ultimately resulted in mine closure and reallocation of resources to a new mine with better forecasted conditions.INTRODUCTIONThe role of a geologist in assisting coal mining operations to understand and predict the impact of varying geological factors on mining productivity is a critical one, especially when management decisions must be made about the future prospects of a mine operating in difficult conditions. Chase, Newman, and Rusnak (2006) provide a very thorough discussion of the evolution of the role of the coal mine geologist and emphasizes the importance of understanding geology with regard to mine management decisions. Using actual mining performance data to determine which geologic factors are the most critical for mining is a powerful tool for making informed mine management decisions. For example, Nelson, Mullennex, and Miller (1988) provide a case study of analyzing the geologic factors impacting productivity of a Kentucky longwall mine to predict future mining conditions for the operation. In that case, the difficult geologic factors for longwall mining were prevalent across much of the remaining permit area and, in response, mine management converted the operation from a longwall operation to a continuous miner (CM) operation to better adapt to the geology. In another example, Keim and Miller (1999) evaluated geologic conditions impacting a West Virginia longwall mine. In both examples, significant geotechnical and geological information was available, including the opportunity to compare predicted mining conditions against actual conditions as mining progressed. Numerous examples of advanced Geologic Hazard Mapping (GHM) methodologies have come from government agencies and academia. For example, development of the Coal Mine Roof Rating (CMRR) system (Molinda and Mark, 1994) provided a standard means for geologists and engineers to communicate quantitatively with regard to mine roof conditions, and the introduction of the Stability Mapping System (SMS) provided an efficient means for analyzing numerous factors affecting coal mine stability (Wang and Heasley, 2005)."

Jan 1, 2019

By J. O. Marsden

Parts I and II in this series of papers presented the chemistry of medium-temperature pressure leaching of copper sulfide concentrates and reviewed the metallurgical development of a process to effectively recover copper using medium-temperature pressure leaching and direct electrowinning (DEW). Key features of the process were the use of superfine grinding of the concentrate (to a P98 of 12 to 15 µm and P80 of 6 to 7 µm), pressure leaching at 160ºC and 1,380 kPa (200 psi) oxygen overpressure, DEW to produce LME Grade A cathode, recycling of the lean electrolyte to the pressure leaching step and treatment of a lean electrolyte bleed by solution extraction (SX). Recycling of the lean electrolyte provided all of the acid required to effectively dissolve copper and convert approximately 65% to 70% of the sulfide sulfur to elemental sulfur, resulting in an ?acid-autogenous? process referred to as the ?MT-DEW-SX? process. This paper (Part III) discusses the steps taken to develop and complete a large-scale demonstration of the process at Bagdad, Arizona, in 2005.

Jan 1, 2007

By M. van Elp, R. Saitua Nistal, P. J. M. Groot

Demand for construction raw materials depends on investment in housing, other buildings and infrastructure. The provision of these materials requires early knowledge of future trends in construction investment. By using scenarios possible future developments and bandwidths can be explored. Policy makers in government organisations as well as in the private sector can base their policy decisions upon these insights. In this paper we discuss the case of sand and gravel in the Netherlands. We will show that, depending on the future role of government and the degree of internationalisation, the long term demand for construction raw materials will strongly diverge. Nevertheless there are some common developments such as a decreasing population growth, a smaller share of the labour force in total population and a growing wealth. In different scenarios we will encounter different conditions for minerals provision and for sustainable development.

Jan 1, 2011

By J. D. Potts

Dust surveys were conducted at six underground coal mines to determine if deep-cutting practices expose face workers to higher levels of respirable dust. The surveyed mines were able to successfully mine deep cuts without significantly increasing the dust exposures of face workers. For exhausting face ventilation, field data indicate that scrubber airflow is the most important factor for controlling dust. Data collected for this study indicate that 20-mesh screens should be cleaned for every 40 ft of advance because 22% of the deep cuts surveyed for this study experienced a 20% to 35% decrease in scrubber airflow over the course of the cut. For blowing face ventilation, field data and past research indicate that dust control is aided by maintaining a proper curtain-to-scrubber airflow ratio of 1.0 (measured before scrubber activation) as well as a curtain setback distance that allows the miner operator to stand at the mouth of the curtain for the entire cut. Dust levels on the bolting faces did not appear to be affected by the longer cycles associated with deep-cut mining when good ventilation practices were used.

Jan 1, 2011

By B. Asbury, M. Cigla, C. Balci

The Western Mining Resource Center (WMRC) at the Colorado School of Mines (CSM) received a grant from the National Institute for Occupational Safety and Health (NIOSH) to perform a study that will help reduce the amount of respirable dust generated from the cutting of coal. The study is based upon laboratory testing and field experience. This information is being used to develop a new cutterhead design in conjunction with Joy Mining Machinery. The new cutterhead design is being evaluated with existing computer models developed at CSM. The new continuous miner cutterhead will be tested at the Twenty Mile Coal Company’s Foidal Creek Mine. Baseline testing with the current cutterhead will also be performed. This paper presents laboratory test results, design methodology, and test results performed to date.

Jan 1, 2002