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By B. N. Conley, K. D. Luxbacher

"The underground coal mining industry in the United States has recently seen the occurrences of several high profile, multi-fatality events. The explosions that occurred at the Sago Mine in 2006, the Darby Mine in 2006, and the Upper Big Branch Mine in 2010 have caused a ripple in an otherwise steadily improving safety record. These events transpired in the midst of an unprecedented level of government regulations and modern safety technologies. The recent increase in fatal events in conjunction with a minimal decline of both fatal and non-fatal injuries over the past decade may signify that current safety practices have reached a level of diminishing returns. Risk management, a safety approach that has been successfully applied in various industries including mining across the world, may provide a means to surpass the safety plateau in the U.S. RISKGATE is an Australian risk management program for mines that shows great potential for application in the U.S. However, fundamental differences between the coal mining industries in Australia and in the U.S. prevent direct implementation. This paper discusses aspects of the RISKGATE body of knowledge that require some adaptation before this program may be applied to the U.S. mining industry. INTRODUCTION The underground coal mining industry in the United States has recently seen the occurrences of several high profile, multi-fatality events. These events transpired in the midst of an unprecedented level of government regulations and modern safety technologies. The recent increase in fatal events in conjunction with a minimal decline of both fatal and non-fatal injuries over the past decade may signify that current safety practices have reach a level of diminishing returns. In order to combat this stagnation in performance, a modification to the manner in which the mining industry approaches worker safety may be warranted. The implementation of a risk management based approach presents a potential method for not only surmounting the current safety plateau but also for achieving the long desired objective of zero harm. RISKGATE a risk management body of knowledge designed for the Australian mining industry that shows great potential for application in the U.S. This paper discusses aspects of the RISKGATE body of knowledge that require adaptation before implementation in the U.S. mining industry. These adaptations are based on differences in operating practices and governmental regulations. This discussion will focus on the three major U.S. risk areas of explosion prevention, ground control, and moving equipment."

Jan 1, 2015

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 Mahmoud Sepehrmanesh, Verya Nasri, Maziar Partovi

"This paper presents an assessment of the impact of tunneling and its associated risks on pile foundations located in the influence zone of tunneling operation. Tunneling in proximity of pile foundations introduces deformations in piles and in turn induces additional axial and bending forces. In modern mechanized tunneling, ground convergence is controlled through balancing the earth pressure at the tunnel face as well as applying pressurized bentonite through the shield. Reducing ground deformation can consequently lower the additional deformations and forces developed in the pile foundation and lessen the associated construction risk. In this paper, comprehensive detailed finite element modeling was performed to quantify the effect of the different parameters on induced forces in piles. Finite element models took into account the nonlinear behavior of soil and pile-soil interface. The modeling results are of practical importance in risk evaluation of tunneling in vicinity of pile foundations. INTRODUCTION Tunneling operation in congested urban areas becomes more frequent as demand for further utilizing underground spaces grows. In urban settings, it is not uncommon for tunnel designers to plan a tunnel route in close proximity to other structures to satisfy other competing objectives like raising the alignment to reduce excavation volume. Setting the alignment close to existing structures increases the risk involved in the project. It is the responsibility of the designer to thoroughly identify, assess, and mitigate all design risks involved. In this paper, we focus on the aspects involved in tunnel construction in proximity to existing pile foundations. Tunnel operations introduce deformation in the soil mass. Consequently, a pile located within deformation zone experiences extra forces as a result of the imposed deformation. The developed forces and bending moments can be in orders comparable with the pile capacity depending on the relative horizontal proximity of the tunnel and the relative depth of tunnel with respect to the pile length."

Jan 1, 2016

By Ehsan Alavi, Sanjeer Yogendran, Savreet Singh

The Don River & Central Waterfront Coxwell Sanitary Bypass Tunnel Project in Toronto extends approximately 10.5 km from Ashbridges Bay Treatment Plant west under Lake Shore Boulevard, north under Bayview Avenue and east through the Don River park area to the Coxwell Ravine Park. This project includes the installation of five intake shafts connected by 10.5 km of 6.3 m internal diameter tunnel and eleven drop shafts and vent shafts, connected to the tunnel by a series of adits. During the excavation of one of five intake shafts (20 m in diameter and 52 m deep), significant volumes of free phase oil and hydrocarbons were encountered. Due to the heavy inflows of the contaminants, excavation was stopped at the transition depth. The initial support of excavation needed to be redesigned, shaft had to be backfilled with CDF and installation of deeper secant piles are in progress to cut off contaminants. This paper outlines the initial plan for excavation as well as the design changes to the plan. The current status of the shaft excavation and lessons learned will be discussed.

Jun 13, 2021

By Glenn Mongillo

Discrete Element Method (DEM) software has been successfully used to simulate various machine/soil interactions and provide insight for industries such as mining and bulk material processing. This paper will investigate typical calibration techniques used in particle models for DEM simulation and physical calibration experiments with soft ground TBM cutting tools to incorporate parameters such as tool drag forces that contribute to required TBM torque. With a well calibrated DEM model, it is expected that TBM simulation results will be more meaningful and provide better insight into TBM performance, power requirements, cutting tool placement, and overall cutter head design.

Jun 13, 2021

By Stephen R. Brown

Current conditions in the gold market demand that mine and plant operators make budgeted production targets at the lowest possible unit costs. For those companies bringing new gold pro­duction capacity on-line, achieving budgeted production levels as quickly as possible after start-up is vitally important to mini­mize unit costs and to begin a positive cash flow. Whether the objective is to simply improve unit costs or successfully start-up a new, complex plant, success will be strongly influenced by the skill levels of the operators and supervisors. The only way to assure return on plant investment, and to survive during depressed metal prices, is to ensure that plant operators have the knowledge to effectively run the plant. Technology available in computer-based, multimedia training systems, including: inter­active animation, videos, voice-overs, schematics, and text can now be used to train operators at their own pace using plant-spe­cific information. Additionally, it has been shown that learning through multimedia provides a higher degree of long term reten­tion than more traditional learning methods.

Jan 1, 1998

By Daniel T. Brian, O&apos

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summary. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition, and development planning are presented in this paper.

Jan 1, 1969

By Peter G. Sechiari

The Rio Tinto-Zinc Corporation Limited (RTZ), through it exploration company Riofinex, commenced exploration for bauxite in the Amazonia region of Brazil during 1970. Following' encouraging indications, exploration licences were taken out and an exploration programme was initiated In February 1975, a preliminary 'feasibility report indicated that a project, based on the Miltonia plateau located close to the town of Paragominas in the State of Para, was viable and that barging might offer an economic solution to getting the product to an ocean-going port. A, decision was taken in April 1975 to proceed with a full feasibility study. In the latter stages of the study, an engineering consortium of Mendes Junior and Bechtel do Brasil was employed to review, and modify if necessary, the concepts that RTZ had developed for the project's operation. With these concepts agreed, the consortium was requested to make capital and operating cost estimates, and these became available during February 1978. The deposit is being developed by a Brazilian company Mineracao Vera Cruz S.A. (MVC) in which the present share-holding is owned 64 percent by RTZ and 36 percent by Companhia Vale do Rio Doce (CVRD). RTZ is a British based international group of mining and industrial companies with interests in almost every major metal and fuel. CVRD is a Brazilian mining company, 85 percent owned by the Brazilian Government, with a major interest in iron ore and also other non-ferrous metals. It is intended, in due course, that the company will become majority owned by Brazilian interests.

Jan 1, 1979

By S. E. Sankey

High anionic functionality acrylamide co-polymers and poly(sodium acrylate) are used as red mud flocculants in bauxite processing operations. These synthetic polymers are effectively displacing starch as the dominant polymer in red mud settling. The performance of these polymers is primarily dependent on the bauxite mineralogy, the alkalinity of the red mud slurry, and the anionic functionality and molecular size (viscosity) of the polymer. In this paper, the physical and chemical properties of the synthetic watersoluble polymers will be reviewed. The relationship between polymer structure and red mud slurry properties as they control polymer performance in settling red muds common to digester and washer circuits will be illustrated. The availability of polymers of varying functionality and viscosity will permit bauxite processors to make significant improvements in the economics of red mud disposal and valuable reagent recovery.

Jan 1, 1982

By C. D. Litton

When methods to prevent the occurrence of fire in underground mines fail, the next line of defense is to rapidly and reliably detect the developing fire, so that subsequent evacuation and control procedures can be safely and successfully implemented. To provide this capability requires an understanding of the operational principles of different types of fire sensors, their merits as well as their limitations, and performance characteristics of the monitoring systems that control and process sensor data; an understanding of how fires develop and the different types of fires that can occur, along with their characteristics and the hazards they present; an understanding of the impact of the mine environment and routine mining activities, not only in terms of these effects on fire sensors but also in terms of the impact of mine ventilation and mine geometry on fire growth, fire characteristics and the detection process. All of these factors are components of the technology of fire detection, and when insufficient knowledge of any of these components exists, the ability to implement adequate mine fire detection systems is diminished. Within the last decade, significant advances have been made in fire detection technology applicable to underground mines. These advances include not only the development of improved sensors and better monitoring systems, but also an expanded understanding of how to deploy sensors, set sensor alert/alarm levels, account for ventilation effects, etc. In addition, there has been an increase in our knowledge of the types of fires that occur, the types of combustibles involved, characteristic times for fire growth and development, the levels of heat, smoke and gas that are produced and the hazards that result. It is the intent of this paper to provide not an overview of current mine fire detection technology and, also, to present data obtained for some smoke sensors that have potential for use in underground mines. The paper will also discuss the data, information and resources that are currently available and seek to identify those areas most in need of further research and development.

Jan 1, 2011

By D. M. Hausen

Carbonaceous gold ores are ubiquitous to virtually all of the Carlin-type gold deposits along the Carlin gold belt in north central Nevada, representing the unoxidized "zones" of presumably extinct thermal spring systems of mostly Tertiary age. A period of subtropical weathering resulted in deep sub-lateritic zones in most deposits to several hundred feet below surface. Carbonaceous ores below this supergene profile of weathering have been investigated by various methods, including petrographic study, standard geochemical and organic carbon analyses, carbon and hydrogen isotopic ratios, electron-spin resonance spectra, infrared spectra, and DTA techniques. Results have been integrated with recent findings by other investigators utilizing fluid inclusion and thermal brine data to indicate a first phase hydrothermal solution temperatures and pressures at a minimum depth of 6 km under normal geothermal gradient. This phase resulted in the quartz-barite-calcite vein filling of the host rocks. Gold mineralization took place later at shallower depths. Primary organic material in carbonaceous ores from the Carlin and other mines appears to be a pyrobitumen residue derived from an old oil pool that had been heated by the thermal solutions, and from which the light hydrocarbon fractions were removed. Some of the bitumen was remobilized along silicified veinlets in the ore, but its role in the emplacement of the gold, itself, is not clear. The gold was localized submicroscopically in fine pyrite, mostly in framboids, and as fine metallic particles, but does not appear to be concentrated within the carbonaceous matter per se. However, reducing conditions associated with bituminous residues are believed to have been favorable for gold deposition.

Jan 1, 2013

By Muhammad I. Kabir

A new minitest of in situ uranium leaching processes at reservoir conditions is proposed. The test which consists of a single observation/ production well and two observation wells is designed to permit the evaluation of both restoration and leaching parameters. It is shown that by using a straight forward history matching procedure, sometimes called a type curve analysis, both the rate of leaching and the ultimate uranium recovery can be evaluated based on the results of the test. Type curves are presented for the case in which the reaction rate is kinetically controlled and there are no other minerals competing for oxidant. Other situations can be approached using the same techniques as those presented here.

Jan 1, 1981

By Andrew Cho, Changsoo (Kevin) Moon, Richard Flanagan, Brian Larsen

"INTRODUCTION Project Background The U.S. Army Corps of Engineers (USACE)/Port Authority of New York & New Jersey (PANYNJ), as part of their New York and New Jersey Harbor Deepening Project, will dredge this shipping channel to a depth of 16.5 m below mean low water (MLW). By deepening the channel, the new generation of larger, “post-panamax” container ships coming to U.S. waters as a result of the expansion of Panama Canal can be accommodated in local marine terminals, helping to retain the nearly 300,000 jobs and $12 billion in annual wages the PANYNJ provides to the region. The existing siphons are situated at a depth that could be compromised by the planned dredging of the channel (nycedc.com). The purpose of this project is to build a new 1.83 m diameter water main inside a 3.66m diameter tunnel replacing the two existing siphons in order to provide the necessary backup water supply to Staten Island across the Anchorage Channel within the Upper New York Bay from Brooklyn. The proposed tunnel is approximately 2.9 km long and at a depth of at least 26 m below MLW. The project is funded jointly by New York City’s Department of Environmental Protection (NYCDEP) and PANYNJ and is managed by New York City Economic Development Corporation (NYCEDC). The contractor of the project is Tully/OHL JV, the designer is CDM/HMM JV, and the CM is LiRo/PB JV. History of New York City’s Soft Ground Tunneling The New York City area has a relatively long history of soft ground tunneling, commencing in the late 19th century. Construction of the first Hudson River tunnel crossings was begun (but not completed) in 1874 for the Hudson & Manhattan Railroad using compressed air supplying a shield. The work continued intermittently until the project finally opened for service in 1907. These 1.72km long tunnels (maximum depths of 29 m) are still in operation and now operated as the PATH Tunnels. They are approximately 5.5m diameter utilizing cast iron segments. The river bed consisted of primarily silt with shallow rock near the New York side. Air “leaks” occurred during the compressed air excavations resulting in some serious “blows” with water and soil entering the tunnel, including one incident with 20 deaths."

Jan 1, 2016

By M. Sears, W. H. Su, J. Wickline, M. A. Van Dyke, G. Esterhuizen, Z. Khademian

It is commonly recognized that seismicity can be induced by rock failures or slip along geologic structures around mining excavations. The unpredictable nature of these events and their proximity to the working area may raise safety concerns in underground mining operations. Modeling can be a useful tool for estimating seismic potential for a given mine layout, but the challenge is to detect a seismic event and estimate its intensity in the model. One well-documented approach is to monitor the variation in the energy content of the model and record potentially damaging seismic events when there is a significant release of energy. Researchers from the National Institute for Occupational Safety and Health (NIOSH) employed this approach using 3DEC modeling software to simulate the anomalous seismic events that occurred in a deep longwall mine in Virginia in 2005. A four-panel model of the mine was constructed utilizing a 2D cross section at the location of the mining face at the time of the event. Seismic potentials associated with the development of each panel are evaluated by recording the seismic energy released during the simulation. The results demonstrate the occurrence of two relatively significant events during the mining of the last panel, which are consistent with the historical observations at the mine.

Apr 26, 2022

By F. Ikumapayi

In order to predict and minimize detrimental production problems due to the recycling of process water in sulfide ore processing, the influence of major species, calcium and sulfate in process water on sphalerite flotation was investigated through Hallimond tube flotation, zeta potential, diffuse reflectance Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) measurements using sphalerite mineral sample. Assessment of process water species in flotation was done using deionized water, process water and simulated water containing calcium and sulfate ions in experiments. Hallimond flotation shows increased sphalerite float-ability in process water compared to deionized water, but no significant effect on the presence of calcium and sulfate ions in deionized water using isobutyl xanthate as a collector. The presence of calcium ions reduced the sphalerite?s negative zeta potential, while at higher concentrations, a charge reversal occurred, at about pH 11. FTIR and XPS studies revealed the presence of surface-oxidized sulfoxy and carbonate species on sphalerite at pH 11.5 in deionized water, process water and water containing calcium and sulfate ions. These surface species do not influence xanthate adsorption.

By R. Ramesh

Understanding the nature of coal surface heterogeneity is a prerequisite to accurate characterization and efficient control of coal surfaces. New techniques based on the centrifugal immersion of particles from the liquid/ vapor interface and film flotation have led to independent estimation of surface energy distributions in individual coal particles. Changes in the distribution of surface sites due to oxidation and polyacrylamide adsorption on coal are studied here using the above techniques. New information on -possible conformations of adsorbed polymers is also obtained.

Jan 1, 1989

By Vernon N. Cox

From comments and questions concerning the meaning of USNR, and "why is the Navy in the mining business?" I believe it is worth while to establish the background and purpose of our company. We are a stock company formed by the purchase and reorganization of a company known as the U. S. Natural Gas Corporation. In May 1969, a group of investors with Mr. Robert L. Katz as president and chief executive officer, created United States Natural Resources, Inc., to develop and purposively use our Natural Resources in four areas: 1. Mines and Minerals 2. Forest Products 3. oil and Gas 4. Recreational Lands As final proof that we are not a government organization, I simply state. "We pay taxes." The mining division was formed in October 1969, with the completion of the merger of USNR and Vibration Measurement Engineers, Inc., Of Evanston, Illinois. Throughout the industry we were known as "VME," our company supplied consulting service in the field of seismic energy control, mining consulting and. we operated drilling, blasting and, contracting organizations in several areas of the country. Since that time we have developed and acquired producing properties in Quarrying, Coal Mining and Cement Copper Production.

Jan 1, 1971

By I. E. Odom

The rare magnesium-lithium clay mineral hectorite occurs at many places in the McDermitt caldera of Nevada-Oregon. Commercial development of several high purity deposits began in 1986. The hectorite was precipitated in a lake environment formed after collapse of the McDermitt caldera. Hectorite beds and lenses are associated with volcaniclastic sediments, limestones, dolomites, zeolites and locally sandy bentonites. The high purity deposits appear to be associated with hydrothermal areas. The hectorite consists of extremely small flake-shaped crystals, and Ca is the predominant exchangeable ion. Its color ranges from white to light green. Commercial uses developed to date include high brightness magnesium aluminum silicate products, organophilic clays, pulp retention, and ceramics. The MAS is used as a suspending agent, binder, stabilizer and thixotrope in aqueous solutions for cosmetics, household cleaners, pharmaceuticals and miscellaneous industrial applications. Organoclays are used in printing inks and paints.

Jan 1, 1992

By A. L. de Vegt

Hydrogen sulfide is an expensive chemical used in nickel, zinc and copper mining and metallurgical operations for selective recovery and concentration of metals from leach water streams, acid plant blow down streams, refinery electrolyte bleeds and precious metal plant bleeds. Hydrogen sulfide is either produced on site by catalytic reduction of elemental sulfur or transported to the site as liquefied hydrogen sulfide (H2S) or as a sodium sulfide solution (NaHS). Biologically produced hydrogen sulfide has economically very interesting application possibilities in the mining and metallurgical industry. Converting sulfates from waste streams into usable hydrogen sulfide by biological reduction results in operational cost savings in existing lime treatment systems. H2S can be produced biologically for less than $500/ton S. For the past ten years Paques has been engaged in the development and installation of treatment systems based on biotechnological processes to remove sulfur compounds from water, air and gaseous streams. Paques has designed and installed a groundwater treatment system for the Budelco zinc refinery in the Netherlands to remove sulfate and heavy metals. The hydrogen sulfide produced is used for recovery of metals, mainly zinc, from the ground water stream. The system has been operating since May 1992 treating a flow of 5000 m3/d. At Kennecott's Bingham Canyon Utah copper mine a pilot plant started operation in November 1995 to develop the process for selective recovery of copper from leach water using biologically produced hydrogen sulfide from sulfate containing groundwater. Other pilot plants are operated at DOE's Pittsburgh Research Center and at Cominco Research focusing on selective recovery of metals.

Jan 1, 1998

By S. C. Tadolini

The use of resin-grouted cable supports to control large ground movements in several types of underground mines has increased substantially since being introduced in 1991. Cables offer several advantages over traditional support systems, having large support capacities coupled with the flexibility to be used in low openings. Cable slings have been designed to be installed on-cycle using no-spin technology or a two-piece unit that can be placed with hand-held drilling equipment. Additionally, yielding cable supports have been developed and are being used to control large amounts of movement in coal and evaporite deposits.

Jan 1, 1998