Search Documents

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 Arthur D. Silber

The economic success and growth of any metropolitan region depends on mobility. Today, mobility between New Jersey and New York is threatened by a transportation system that cannot meet 21st century travel demands. The transportation bottleneck created by the Hudson River threatens the viability of one of the world?s great centers of commerce and culture. Fortunately, there is a solution: The Access to the Region?s Core Mass Transit Tunnel. The US$8.7-billion Mass Tran-sit Tunnel?s (MTT) new two-track line will double commuter rail capacity under the Hudson and create a new, state-of-the-art cavern station in Midtown Manhattan, with wide platforms, high-speed escalators and other features to improve riders? travel experience. The capacity and other benefits of the MTT project will launch a new era of prosperity for the region, just as the Pennsylvania Railroad did almost 100 years ago when it built the existing two, single-track rail tunnels that now form the sole commuter rail link between New Jersey and New York. The existing tunnels run from North Bergen, NJ, under the Hudson River to Pennsylvania Station at 33rd Street in Manhattan. Construction on the MTT, the largest public works project in the United States, is scheduled to start this year and continue through 2017. The MTT is ready to go to construction thanks to a major commitment of financial, engineering, project management and other resources from NJ TRAN-SIT, New Jersey?s statewide mass transit agency, and the Port Authority of New York and New Jersey, a bistate agency that operates the Holland and Lincoln tunnels, the George Washington Bridge and other major transportation facilities in New York and New Jersey. The project is also strongly supported by the state governments of New York and New Jersey, as well as that of New York City. The MTT is New Jersey Governor Jon Corzine?s number one transportation priority.

Jan 1, 2009

By D. Parks, A. Miller, M. McNinch, R. Jacksha

Each year, hundreds of mine workers are involved in machinery-related accidents. Many of these accidents involve inadequate or improper use of lockout/tagout (LOTO) procedures. To mitigate the occurrence of these accidents, new safety methods are needed to monitor access to hazardous areas around operating machinery, improve documentation/monitoring of maintenance that requires shutdown of the machinery, and prevent unexpected startup or movement during machine maintenance activities. The National Institute for Occupational Safety and Health (NIOSH) is currently researching the application of Internet of Things (IoT) technologies to provide intelligent machine monitoring as part of a comprehensive LOTO program. This paper introduces NIOSH’s two phase implementation of an IoT-based intelligent machine monitoring system. Phase one is the installation of a proof-of-concept system at a concrete batch plant, while phase two involves scaling up the system to include additional sensors, more detailed safety/performance metrics, proximity detection, and predictive failure analysis.

By C. Sykes, E. Turner, M. Wyart-Remy

This paper follows that of the Milos Conf, 2002 and examines the collection and reporting of SDIs in the industrial minerals industry in Europe. It compares the characteristics of the GRI Reporting Guidelines, with its Metals and Mining Sector Supplement with those of the EU DG Enterprise Scheme, launched in 2001. The particular issue of SME's and companies which are not publicly traded is examined. The pros and cons of participating in such schemes is a central theme of the paper. The paper concludes that there and many business benefits for these companies in participating and submitting their data. The European Commission Scheme is strongly recommended for companies in the sector which are SME's and not-publicly traded as well as large firms who are listed on European Stock Exchanges.

Jan 1, 2005

Underground mine designs typically try to avoid extraction beneath streams and rivers of any significant size, especially when the overburden rock thickness between the stream bed and the mine is thin. Potential issues with mining beneath streams include excessive groundwater inflow to the mine; weak ground (roof, floor, and pillar) conditions; horizontal stress effects; as well as stream loss and other potential adverse environmental effects. However, there are times when crossing beneath a stream or river is necessary to move into a new area of mineral reserve without creating additional mine access points from the ground surface. Often, stream crossings are completed without thorough assessment, potentially resulting in increased costs, decreased safety, and, in some cases, failure to advance the mine. Selection of the most favorable location(s) to cross the stream must account for numerous factors and the associated assessment often requires a multidisciplinary approach. Stream crossing investigations often require geological, hydrogeological, geotechnical, and geophysical expertise. Phases of stream crossing investigations include desktop evaluation of maps and aerial photography, stream bed observations, drilling, detailed rock core logging, downhole geophysical surveying, hydraulic conductivity testing (packer testing), geotechnical laboratory testing, assessment, and reporting. The deliverables from a stream crossing assessment typically include geological, geotechnical, and hydrogeological characterization of potential stream crossing locations; classification of favorable and unfavorable crossing locations; recommendations for entry design and pillar sizing; and recommendations for if, and how, to conduct pre-grouting activities. Examples of technical aspects of data collection and assessment are provided based on decades of industry experience conducting stream crossing assessments in various underground mining scenarios.

Jul 28, 2020

By G. Coombs, L. Meade, J. Welshimer

Industrial Minerals commodity profiles are continued from May's Annual Review issue. Diatomite G. Coombs, Manville Sales Corp. Growth in US diatomite production continued to lag in 1986. The US Bureau of Mines estimated that 580 kt (640,000 st) were produced last year. This is a 1%0 growth over 1985. The cumulative growth from the 1982 low point is 4.4%. Present production, though, is still only 90% of the high tonnage of 1979. The industry will see increased competitive activity with the start-ups of two new mines and production facilities in California and Oregon. US production has come primarily from Lompoc, CA, Bassalt, Clark Station, and Lovelock, NV, and Quincy, WA. New production, probably with capacities of 45 kt/a (50,000 stpy) each, have started near Burney, CA, and Vale, OR. Eagle Picher's new, full-line filter aid and filler plant at Celatom, Vale, OR, was dedicated in August. The plant uses diatomite from the Celatom mining district in Juntura, OR. Grefco's new filter aid and filler plant near Burney, CA, was ready in July. It produced flux calcined products through a single kiln and can handle both bag and bulk shipments. The operations are in Shata County with the plant and mine at the same site. Manville Specialties Group is moving its Filtration and Minerals Division headquarters and research staffs to Lompoc, CA. The move is intended to strengthen response and performance by locating research, marketing, and production close together. Diatomite is processed in three methods: natural, calcined, and flux calcined. The natural is dried to remove water and is particle size classified. Calcined or straight calcined products have been sintered to modify particle size or permeability. Flux calcination, or flux sintering, has a stronger influence on permeability and also benefits color. The unique structure of diatomite is used in a range of particle sizes from fine paint fillers, to coarser filter aids, to granular aggregates. Dimension stone L. Meade, Geomapping Associates Ltd. 1986 was another good year for dimension stone production. The trend toward using marble, granite, limestone, sandstone, and slate has created an increasing demand. According to US Bureau of Mines 1986 estimates, 1.1 Mt (1.2 million st) of dimension stone, with a value of $173 million, was produced by 200 companies. This is an increase from 1985, where 220 companies produced 1 Mt (1.12 million st) valued at $172 million. The increased production volume and decreased unit value is due to the competition from imports. The net import reliance in 1986 was 68% compared to 62% in 1985. The value of imports was $374 million in 1986 versus $295 million the year before. In an effort to maintain their market share, domestic finishers, particularly in the granite industry, continued to upgrade plants and machinery during 1986. In addition, offshore dollars have financed a number of fabricating facilities in North America that will finish imported rough stock. It is hoped that this increased domestic production capability will capitalize on a devalued US dollar. The trend has been for growth in stone usage and market. This trend is continuing with increased public awareness and desire for natural stone in buildings. The area of greatest market growth is expected to be in residential and interior decorative stone usage. Use of sophisticated, automated equipment has made the cost more affordable. Now lobbies, foyers, and specialty rooms are being clad in stone. Dolomite J. Welshimer, National Lime & Stone Co. About three-quarters of dolomite production is used as construction aggregates and 10% to 20% is sold or used as an industrial mineral. Total limestone and dolomite consumed for chemical and metallurgical purposes is about 136 Mt/a (150 million stpy). Sales of industrial dolomitic products were somewhat stronger in 1986 than levels recorded in the early 1980s. Some of the sales' strength, however, can be attributed to reductions in the number of active mining and processing operations. The industry will probably undergo further consolidation by the end of this decade. This will be due primarily to the continued softening in demand by the steel industry. Dolomitic limestone deposits being mined for raw materials for the steel, glass, and refractory in¬dustries are generally 54% calcium carbonate and 45% magnesium carbonate by weight. Impurities composed of silicon, aluminum, iron, sulfur, and phosphorous, represent less than 1%. The heaviest concentration of high purity, surface mineable dolomite in the US is in northwestern Ohio. Crushed and sized dolomitic limestone is a basic raw material for the iron and steel industry. It is also used as feed stone or lime kilns. Soft-burned lime is a popular raw material for BOF steel production. It is also used extensively in insulating glass fiber manufacturing. A related material, hydrated

Jan 6, 1987

By Glen Church, Don W. Deere, Christoph M. Goss

The Standley Lake Dam Rehabilitation Project in Colorado included the complete replacement of the outlet works. This required two 1.8m (6 ft) diameter microtunneled wet lake taps, 380m and 186m (1246 ft and 636 ft) long, a permanent valve shaft 12.2m(40 ft) wide and 32m (105 ft) deep, and a 3.5m (11.5 ft) diameter (962 foot long) outlet tunnel driven with a roadheader. The tunnels were driven in low-strength, expansive, and slickensided claystone. The paper addresses the site investigation, shaft construction, roadheader performance, shotcrete placement, tunnel convergence, long distance microtunneling, and wet lake taps.

Jan 1, 2005

By S. K. Gilman

Zircon (ZrSiO4) sand production of about 1.1 Mt/a(1.2 million stpy) predominates the global supply of zirconium minerals. Baddeleyite (ZrO2) contributes less than 1 percent of supply. Zircon is almost exclusively produced as a co-product from the mining of titanium minerals, mainly from mineralized beach sands. In 2004, there were a number of new projects under consideration that were more dependent on zircon revenue than for titanium minerals. This reflected sustained higher zircon prices and forecast ongoing supply shortages in the absence of major new discoveries.

Jan 1, 2005

By Paul D. Klipfel

Introduction Mineral exploration interest, principally for gold, in the south-western Pacific has surged to new proportions. This is primarily due to the application of epithermal exploration concepts in the Australian-Oceana region. Other factors that have contributed to the high level of exploration interest include governmental policies supportive of mineral exploration, along with relative ease of tenure access and a relatively short bureaucratic process. This paper highlights exploration and development activities in the North Island of New Zealand, Fiji, Vanuatu, the Solomon Islands, and Papua New Guinea (Fig. 1). It provides a framework to understand the overall recent enthusiasm that has been brought to the south Pacific by explorationists. Through these recent developments, it is clear that the south Pacific region will become a significant gold producing area and thereby worthy of attention and study. Papua New Guinea alone is the free world's seventh largest producer (Table 1). And, with the addition of production from deposits presently being developed, this status is likely to be raised. History Gold was first noted on various Pacific islands in the late 1500s by Spanish explorers. They thought they had reached the legendary King Solomon mines. Since then, the history of prospecting in the southwest Pacific has coincided with the colonization of the region. Settlers in New Zealand extensively mined alluvial and lode gold deposits starting in the 1850s. The spread of European colonization to the more remote Pacific islands from 1880-1940 was accompanied by varying degrees of prospecting activity by planters, traders, and settlers. Some were successful, others may have been successful, but never returned due to hostile indigenous peoples or disease. In general, records of such prospecting activity are meager and exploration leads are, in some cases, gained through local village folk memory. Most early discoveries were alluvial finds. These led to placer operations, particularly in New Zealand, the Solomon Islands, and Papua New Guinea. Continued prospecting located lode deposits such as the Morobe Gold-field of Papua New Guinea, the Coromandel Peninsula of New Zealand, and the Emperor of Fiji. Some areas were prospected thoroughly. Yet others, such as Vanuatu, remained relatively unexplored until the present exploration surge began. During World War II, interest in minerals was diverted. It was renewed significantly until the middle 1960s and early 1970s when regional porphyry copper exploration was conducted.

Jan 10, 1987

Two miners were fatally injured when a pillar bump occurred during retreat mining in a southern West Virginia coal mine. The mine was operating in the Eagle seam with overmining in the No. 2 Gas and Powellton seams. A coal bump is defined as a sudden and violent failure of coal caused by the release of stored strain energy in the pillar. While significant strides have been made by academia, industry, and regulatory agencies to better understand bump conditions and mitigation techniques, coal bumps represent a long standing, highly site-specific engineering problem in which the exact failure mechanism(s) is not clearly understood.

Jan 7, 2020

By Martin Herrenknecht

The world?s growing population and rapidly proceeding urbanization are boosting an enormous demand for new and high-capacity infrastructures to secure the mobility of goods and people. Densely populated areas face the challenge to provide efficient traffic infrastructure, such as a modern public transportation system. At the same time, the maintenance and modernization of supply and disposal structures for water, sewage, energy and communication are also essential. Additionally, supra-regional transportation routes such as long distance water diversion schemes are the challenges for the future. All these projects are as demanding as they are characterized by a tight time schedule.

Jan 1, 2010

By B. Farshadi, B. Asi, M. J. Habibian

"Dare-Zereshk deposit is one of the deposits supplies ore for Taft copper Complex in Iran Yazd province. This deposit is situated underneath a village the same name. Prior to mining activities, the village and its agricultural lands should be dislocated and deserted. This paper discusses about sustainability factors in this area including: Social and environmental effects of mining, dislocation and substitution of communities, created and lost jobs, financial and economic factors, quality of life index, infrastructures and post-mining land use. Studies have been performed by coupling Geographical Information System (GIS) with decision support tools such as Multi Attribute Decision Making (MADM), Through these studies revealed that considering the infrastructures developed for mine and plants, earned incomes and changing the community, mining activity in this area not only increases the social and regional sustainability but also improves it to a higher level."

Jan 1, 2011

By J. Bleeck, G. Mahrt

INTRODUCTION Many excellent papers have been written and presented regarding agricultural lime and the subject has been covered extensively in books concerning soil science, fertilizing, limestone, etc. We felt challenged to construct a paper that wouldn’t merely be a repetition of past presentations. Therefore, we chose to begin with factors having the most impact on plant growth realizing that the audience is likely to be relatively unfamiliar with this subject. So, we decided to dig deep into the roots of soil and plant growth science in order to better understand the significant role of limestone in this important area. The soil with the higher plants growing upon it forms an open and dynamic ecosystem in which there is flux of energy and material (heat, light, water, nutrients, mineral and organic matter, organisms). Plants root in the soil and then take up oxygen for root respiration, yielding energy for nutrient uptake, water for turgescence and transpiration and use in photosynthesis and the mineral nutrients needed for the synthesis of organic matter. Above the ground the plant takes in light energy and heat using them in photosynthesis to assimilate atmospheric CO2. Photosynthesis is the basic life process of creation. However, we will look at the root room where soil, water, air, and heat economy and the supply of nutrients determine soil fertility and the important role lime plays here. Location is the primary point to be considered when discussing agriculture (climate and soil); secondly, the dynamic and mobility of the minerals (plant nutrients) in the soil; and thirdly the conversion of organic substances into humus. And then there is a great deal of water involved in the growing process. In order to produce 1 kg of dry plant substance, 300 to 800 kg of water must be pumped through the plant and is then lost by transpiration. Cereals, vegetables, and sugar beets consume between 400 to 500 kg of water during the growing process and long-growing crops, such as alfalfa and clover, can consume 600 to 800 kg of water per kg of finished product. Without water, a plant cannot grow. (Reference 1)

Jan 1, 2006

By M. Rice, M. Stanley, J. Marlow

Arizona construction aggregate industry remains in the crosshairs of public debate, caught between the need for aggregate-based building materials and alternative, high-value land-uses. To better manage lands and improve land-use decisions, the Arizona State Land Department has need for a system to assess potential aggregate resources on State Trust lands, and assign dollar values accordingly. Thereafter aggregate values can be compared to residential, commercial, agricultural, recreational, and habitat values -- in a determination of highest and best land-use.

Jan 1, 2002

By P. H. S. W. Kulatilake

To exploit an underground mine effectively and safely, it is important to have a good understanding of the geotechnical behavior around underground excavations made in the mine. The aim of this study was to investigate the geotechnical behavior around a tunnel excavated in a metal mine in China at the three-dimensional level. Using the information available on lithology, geological structures, in-situ stress measurements, physical and mechanical properties of intact rock, discontinuities and interfaces between different rocks, a three-dimensional numerical model was built by using the 3DEC software to simulate a tunnel excavation under a high in-situ stress condition. Effect of the discontinuity network, possible intact rock and discontinuity parameter variability, representation of rock masses as discontinuum or continuum material and rock support system on the deformation, stress, failure zone and stability around the tunnel was investigated. A very good agreement was obtained between the collected field deformation monitoring results and the results of the conducted numerical stress analyses.

Jan 1, 2012

By Timothy M. Bruner, William J. Maloney

Faced with rapid growth that strained their current water supply capabilities, the Somerset Water Service in Somerset, KY decided to construct a new intake structure on the shore of Lake Cumberland. With an existing intake structure within 200', very hard limestone geology with calcite geodes, and lake level fluctuations as high as 50 ' ,this project posed many challenges. The following paper discusses how mechanical excavation techniques were used to overcome these obstacles.

Jan 1, 2001

Ceremonies for the induction of five mining industry pioneers into the National Mining Hall of Fame will be on Sept. 12, 2009 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. The five inductees are: Paul A. Bailey, 82, Richard T. Moolick, 89, William Braden and Alonzo Pawling and Henry Harnischfeger. Paul A. Bailly was president of Bear Creek Mining Co., the U.S. exploration subsidiary of Kennecott Copper, from 1961 to 1967. In 1968, he joined Occidental Petroleum Corp. and was tasked with creating the company?s international mining division, Oxymin, which he led as president through 1983. During his distinguished career, Bailly participated in numerous significant mineral discoveries, developed a new exploration philosophy and made important additions to the mineral exploration literature. William Braden was the first to recognize the immense potential of the El Teniente orebody in Chile. He founded Braden Copper Co. and developed the El Teniente Mine which now, 100 years later, remains the world?s largest underground copper mine. Braden?s endeavor survives to-day as the El Teniente division of the Chilean state copper company, CODELCO. T. (Dick) Moolick established a lasting legacy in the mining industry, first during a 35 year career with Phelps Dodge Corp. and then as the driving force in establishing the National Mining Hall of Fame and Museum in Leadville. The Hall of Fame and Museum ? a monument to the memory of the men and women who pioneered the discovery and development of the United States? natural resources ? has become one of the fi nest museums in the western United States.

Jan 1, 2009

By J. T. Hollow

The Fort Knox Mine is located in Alaska?s interior, where the average ambient air temperatures range from -24°C (-11°F) in January to 16°C (61°F) in July. The mill processes a free-milling gold ore utilizing both a gravity recovery circuit and conventional cyanide leach/carbon-in-pulp circuits. Mathematical models have been developed to accurately predict the impact of leach circuit slurry temperature on gold leaching, carbon adsorption and cyanide destruction kinetics. Additionally, an energy-balance approach has been used to model the seasonal variations in slurry temperatures throughout the Fort Knox mill. The energy-balance model, combined with the kinetics models previously developed to predict plant performance, was used to justify a tailing thickener installation at the Fort Knox Mine. This paper describes the development of the energy-balance model and its prediction of plant performance assuming a tailings wash thickener to reduce heat loss from the mill. Also presented is an analysis of the post-project plant performance that validates the model and shows that the mine produced an additional 596 kg (19,155 oz) of gold while reducing mill reagent costs by $6,302,000 during the first 38 months of operation.

Jan 1, 2007

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