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By S. Hamm

Elevated total dissolved solids (TDS) content in waters downstream from surface coal mines in Central Appalachia is an increasing concern, as unnaturally high TDS and/or associated specific conductivity (SC) may contribute to deteriorated stream ecosystem health. The aim of this preliminary study was to explore the efficacy of accelerated leaching as a means of minimizing long-term TDS/SC generation by problematic overburden materials. Five spoil samples were collected and leached using simulated rainwater solutions under ambient and acidified pH conditions. SC and pH were monitored during each leach cycle, and ICP-MS was used to determine how leaching conditions affected release of specific ions. This paper highlights the results of both jar and column leaching tests. Among the most significant findings was that, for certain spoil materials, SC in leach column effluent was effectively reduced when spoil was leached first with acidic rainwater followed by ambient rainwater (vs. ambient rainwater leaching alone). This suggests that accelerated leaching might aid in long-term stabilization of some materials.

Feb 23, 2014

By S. A. Smith-Hamm, E. A. Sarver, A. S. Cox

Appalachia is an increasing concern, as unnaturally high TDS and/or associated specific conductivity (SC) may contribute to deteriorated stream ecosystem health. The aim of this preliminary study was to explore the efficacy of accelerated leaching as a means of minimizing long-term TDS/SC generation by problematic overburden materials. Five spoil samples were collected and leached using simulated rainwater solutions under ambient and acidified pH conditions. SC and pH were monitored during each leach cycle, and inductively coupled plasma-mass spectroscopy (ICP-MS) was used to determine how leaching conditions affected the release of specific ions. This paper highlights the results of both jar and column leaching tests. Among the most significant findings was that for certain spoil materials, the SC in the leach column effluent was effectively reduced when the spoil was first leached with acidic rainwater followed by ambient rainwater, as opposed to leaching with ambient rainwater alone. This suggests that accelerated leaching might aid in the long-term stabilization of some materials.

Jan 1, 2015

By W. H. Langer

Large amounts of limestone fines coproduced during the processing of crushed limestone may be useful in the sequestration of carbon dioxide (CO2). Accelerated weathering of limestone (AWL) is proposed as a low-tech method to capture and sequester CO2 from fossil fuel-fired power plants and other point-sources such as cement manufacturing. AWL reactants are readily available, inexpensive, and environmentally benign. Waste CO2 is hydrated with water to produce carbonic acid, which then reacts with and is neutralized by limestone fines, thus converting CO2 gas to dissolved calcium bicarbonate. AWL waste products can be disposed of in the ocean. Feasibility requires access to an inexpensive source of limestone and to seawater, thus limiting AWL facilities within about 10 km of the coastline. The majority of U.S. coastal power generating facilities are within economical transport distance of limestone resources. AWL presents opportunities for collaborative efforts among the crushed stone industry, electrical utilities, cement manufactures, and research scientists.

Jan 1, 2009

By William H. Langer

Large amounts of limestone fines co-produced during the processing of crushed lime-stone may be useful in the sequestration of carbon dioxide (CO2). Accelerated weathering of limestone (AWL) is proposed as a low-tech method to capture and sequester CO2 from fossil fuel-fired power plants and other point sources such as cement manufacturing. AWL reactants are readily available, inexpensive and environmentally benign. Waste CO2 is hydrated with water to produce carbonic acid. This reacts with and is neutralized by limestone fines, thus converting CO2 gas to dissolved calcium bicarbonate. AWL waste products can be disposed of in the ocean. Feasibility requires access to an inexpensive source of limestone and to seawater, thus limiting AWL facilities to within about 10 km (6 miles) of the coastline. The majority of U.S. coastal power-generating facilities are within economical transport distance of limestone resources. AWL presents opportunities for collaborative efforts among the crushed stone industry, electrical utilities, cement manufacturers and research scientists. There is a concern that CO2 generated from human activities is contributing to climatic and environmental changes. Approximately one-third of anthropogenic CO2 emissions come from burning fossil fuels to generate electricity. Each power plant is capable of emitting several million tons of CO2 annually. A variety of other industrial processes, such as cement manufacture, oil refining, and iron and steel production, also emit large amounts of CO2. The level of atmospheric CO2 can be reduced by capturing CO2 from point-source emissions and storing or sequestering it in isolation from the atmosphere (U.S. Department of Energy, 2003). In 1999, G.H. Rau and K. Caldeira proposed a geochemistry-based method that is referred to as accelerated weathering of limestone (AWL) in a paper titled ?Accelerating carbonate dissolution to sequester carbon dioxide in the ocean ? geochemical implications.?

Jan 1, 2009

By Timothy W. Ellis, John A. Howes

The production of lead-acid batteries is defined by a closed-loop product life-cycle. Active material and grid alloys converge on an adaptable specification that improves both performance and recyclability. This mapping of product requirements for lead-acid batteries has taken over 80 years to develop. But, as the use of batteries made with other chemistries continues to grow, the need for a comparable life-cycle management process becomes increasingly apparent given societal needs to manage raw materials, e.g. the European Union Battery Directive recycling targets. What has taken more than 80 years for lead-acid to evolve in a closed-loop paradigm must now be accomplished in less time for batteries using other chemistries and technologies. End-of-life costs are embedded in the product cost of lead-acid batteries. However, end-of-life costs are not reflected in the product cost of batteries made with other chemistries. Those costs are borne by other constituencies with often inefficient and environmentally damaging results. Lead-acid is a materials technology management model for other products.

Mar 1, 2017

By Steven A. Mathe, Seokbin Lim

Current analytical models can accurately predict the final velocity of explosively driven flyers and can somewhat predict the acceleration profile, but do little to address the deformation of the flyers. Explosive systems such as linear shaped charges and explosively formed projectiles, which can be described as multiple interacting explosively driven flyers, often involve interactions between the flyers that occur much before the flyers reach their predicted final velocity. In this regime, it is important to accurately understand both the acceleration profile and the deformation profile of the flyers, as both significantly affect the functioning of the explosive systems. Previous work proposed an analytical model to meet this need. As the expanding gas cloud of detonation products drives the flyers, rarefactions impinge upon the gas cloud from around the flyer edges, which produces a pressure difference across the back face of the flyer leading to deformation of the flyer. Previous research condensed the effects of the rarefactions into a single term, the pressure release ratio, ?, which was calculated based on hydrocode simulations of a block of explosive only and an assumption of isentropic expansion. This work intends to determine the value of ? for different explosive compounds. The results of this analysis were compared to hydrocode simulations of an open-faced sandwich configuration explosive/flyer system with an average accuracy of 15% across the tested compounds.

Jan 1, 2015

By J. Walden, J. Rhoades, R. E. Miller, R. Gibbs, P. Boman

Accelerometers and pressure transducers, mounted in suspension components, can be used to monitor the ride of haulage trucks. Presently, it is difficult to tell what caused a jolt to the truck using either pressure or acceleration data alone. When information from a global positioning system (GPS) is recorded at the same time as shock pressures or acceleration data, the exact location of an event can be determined. Mine management can then determine what caused the jolt to the truck. This research is part of a National Institute for Occupational Safety and Health (NIOSH) project called "Engineering controls for reduction of jolting/jarring injuries in surface mines." NIOSH is investigating how the work environment of haulage truck drivers can be improved. The US Mine Safety and Health Administration (MSHA) notes that, between 1986 and 1995, 60% of the back injuries were to haulage truck drivers in metal/nonmetal surface mining. Personnel from Phelps Dodge suggested that combining acceleration data with information obtained from a GPS could generate results with a variety of uses. Therefore, researchers at the Spokane Research Laboratory (SRL) began investigating how to tie acceleration and GPS data together. It was originally thought that this tool would be used primarily for road and truck maintenance. However, as research progressed, it became apparent that it would also be useful in providing feedback about equipment operations and identifying unusual causes of jolting. Experimental approach Available components that function well by themselves were linked for the purpose of proof of concept. Using a Modular Mining Systems (MMS) product called Vital Signs, SRL researchers took an Aero-Marine Products (AMP) acceleration recorder and hardwired it to MMS Dispatch equipment already installed on a truck. AMP is one of several manufacturers of acceleration recorders frequently used to monitor freight during shipping. MMS Dispatch is used for production accounting and truck dispatching and uses GPS tracking. Through Vital Signs, an analog or digital alarm signal can be recorded. Steve Rhoades, of MMS, wrote unique code that links the Vitals Signs data and GPS location and stores this data in an ASCII log file. SRL researchers installed the equipment in a Caterpillar 793 haul truck. The result was a working prototype. Figures 1 and 2 show the instrument installation in the truck. Discussion From 8:30 pm on Sept. 14, 1998 until 6:50 am on Sept. 15 1998, 899 jolts above a threshold of 2 g (1 g is the acceleration of gravity. It is either 9.81 m/s2 or 32.17 ft/ s2.) were measured on the test truck. Some sections of the haulage road produced most of the events, while

By E Kasai, D Maruoka, Y Konno, T Murakami

The iron ore sintering process produces approximately three per cent of carbon dioxide emission in Japan because a large amount of coke breeze is used as the main agglomeration agent. Therefore, its suppression has been required. A promising method is to replace the coke breeze with biomass char and iron-bearing materials. In this study, the effect of the utilisation of metallic iron with coke or palm kernel shell char (PKS char) as an agglomeration agent on its oxidation behaviour was examined by a series of experiments using a sintering simulator. The use of PKS char leads to a larger decrease in the pressure drop difference of the sintering bed compared to the case using coke. Furthermore, the oxidation rate of metallic iron was larger in the case using PKS char together than that using coke. It was considered that the oxidation of metallic iron was promoted because the bed-temperature increased at a faster rate and achieved a higher temperature.

Nov 8, 2021

By Chu E. Ho

This paper describes a case history involving the use of the Equivalent Driving Energy concept for evaluating timber piles that failed to achieve the termination criterion traditionally based on final driving resistance and minimum pile depth. It was assumed that a pile would be acceptable if the overall energy delivered during pile driving was at least equal to that of an ideal pile that achieved the design pile capacity established during an initial load test. The equivalent driving energy was determined by integrating the cumulative driving resistance profile over the embedded length of the pile within the founding soil strata. The required equivalent driving energy was calibrated using representative restrike PDA capacities of production piles as piling progressed. This approach enabled piles that failed to meet the original acceptance criterion to be re-evaluated, resulting in a significant reduction in the number of rejected piles that would otherwise have to be replaced.

Mineral exploration and mining in New Zealand has had almost five years of new legislation. The requirement for different consents is a challenging, time consuming, expensive exercise but in most cases the new procedure is working, although the matter of obtaining access to land is still a major issue. Priority is critical. After lodgment of an application for a minerals permit there are many other matters to address such as identifying land owners, occupiers and administrators, preparation of access applications, consultation and preparation of various resource consent applications.

Jan 1, 1996

By D A. Vogel

"Sampling may be mandatory for safety or environmental reasons. It may be because the value of a sale needs to be determined or to provide important data for investments. Whatever the reason, an incorrect sample will come at a risk. Only the person that relies on sampling data can imagine what the potential cost of such risk is.Sampling itself has a cost too; the direct cost of a quality control department and indirect cost for interrupting a process, such as stopping a conveyor belt during loading. If all material is the same then only one small sample is enough. But if all the material is different, then a very large sample must be tested; in the conveyor belt scenario it must be stopped very frequently and the associated cost will be high.A good sampling plan finds the proper balance between risk and cost. A good sample must be small enough to handle yet large enough to be representative for what information is required. All good samples have three things in common: there was proper access to the material the sampling tool allowed equal probability of particles being selected nothing was disregarded, everything was included.This too is the core of Gy’s ideal sampling scenario, where all particles have the same probability of being selected and included in the sample. There is risk of bias when part of a lot is excluded from the sample. Extra care is needed when sampling particularly heterogeneous, segregated or layered materials. The sampling tool should never systematically leave out a portion; it shall not push aside large or hard particles. Wet samples shall not stick to the sampling tool. This extends to sample preparation too when reducing particle size and dividing the sample in the process.CITATION:Vogel, D A, 2017. Access, select, include – a review of the commercial sampling of traded bulk commodities in the context of Gy’s Theory of Sampling, in Proceedings Eighth World Conference on Sampling and Blending, pp 367–378 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

May 9, 2017

By Richard Pizzi

Built in 1806, Boston's African Meeting House is the oldest surviving Black church building in the country. A $7 million dollar renovation was begun in 2006 to restore this historic building to its 1855 appearance and to modernize the building's accessibility, electrical and mechanical systems. As part of the restoration, an underground utility room and elevator tower, needed to provide handicap access to the Meeting House, were constructed. Extending up to 17 feet below the foundations of the abutting buildings, the utility room was constructed within one foot of some of Boston's oldest and most expensive residences. All equipment and materials had to enter the work area through a narrow alley rendering conventional methods of excavation and construction of earth support using heavy equipment unfeasible. A unique combination of micropiles, structural cap beam, internal struts and shotcrete facing was designed and constructed to provide the permanent and temporary support of the lateral loads from the earth pressures and adjacent building surcharges and the vertical loads from the elevator tower. The narrow and congested streets of the Beacon Hill neighborhood presented many day-to-day challenges for the contractor.

Jan 1, 2011

Within the research project "Mine Development" funded by the "Austrian Fonds zur Forderung der wissenschaftlichen Forschung (FWF) " (funds for scientific research) between 1991 and 1993 150 underground hardrock mines in Europe, Northern America, Australia and Japan have been visited to analyze their general design and layout. The main aim of the project was to develop strategies for accessing new underground hardrock mines and to establish a mine planning database. The investigation included mines in high developed countries only, with a comparable labor cost situation. This paper presents the results of one part of the project, which deals with investigations into the influence of different parameters on the design of the primary access for a mine.

Jan 1, 1995

By H. W. Hunt

Accessories are increasingly used to protect and extend H, pipe, precast concrete, timber, and sheet piles for any soils conditions. With point protection, piles can be driven through boulders, layered rock, garbage dumps, and waterfront debris to provide dependable support for all types of structures. Splicers for pipe piles can be tapered for a water-tight drive-fit that does not require welding. The pipe splicer can be made applicable to precast concrete piles. Splicers for H make the long pile as strong as an unspliced length with only simple welding. Transition splicers quickly connect different types or sizes into efficient composite piles.

Jan 1, 2010

By Ralph H. Cleland

GENERALLY speaking, the Industry lost ground in 1941 in its accident experience. Though the frequency of compensation accidents was but slightly higher than in the previous year and well below past experience, our fatality rate shot up to that obtaining in 1938, and the average cost per man employed was the highest for some time. The number of fatalities was 56 in 1941 as against 33 in 1940. The average cost of compensation per man employed was $34.25 in 1941 as against $28.43. There was but a slight increase in the number of men employed. Accident prevention efforts were maintained, as shown by our frequency, but our accidents were of a more serious nature. In a period of considerable labour turnover, with many new men entering the Industry, especially the base-metal division, and much mental distraction, we might well have expected a high rate of accidents. That this did not occur is a tribute to managers, supervisors, and workmen alike. We all regret the high fatality rate and one must consider why this occurred. So far as it is possible to determine, there is no apparent explanation. There were no disasters. The accidents occurred to the same class of work-men, both in respect to jobs and age groups, and from the same age-old causes that we all know so well. Luck is a big factor in the seriousness of an accident; the solution lies in preventing accidents, even first-aid cases. Generally speaking, if minor accidents do not occur, major accidents do not occur.

Jan 1, 1942

By Kirk L. Prather

Why discuss techniques of accident prod lot on? Would it not be more useful to discuss means to reduce accidents? This discussion will answer these questions by suggesting ways in which effective accident prediction techniques improve the ability to foresee and prevent accidents. Accident Prediction Process The secret to accident prediction is to utilize the tendency for history to repeat itself. The same circumstances and the same human behavior that produced accidents in the past tend to produce accidents in the present and the future. The ability to predict accident occurence in the future by projecting from the past is a statistical process. In a bookmaker's jargon this means "playing the odds" or "the percentages". A horse or a sports team may be beaten on any given day, but by skillfully assessing the factors of past performance and assigning odds, many clever bettors make money in the long run.

Jan 1, 1973

By Michael G. Zabetakis

Effective accident prevention programs utilize a broad spectrum of activities, including meaningful training programs. In practice, such programs must be directed towards specific, defined needs. These needs are considered here for three categories of employees: new, re-assigned, and experienced.

Jan 1, 1983

By L McCracken

Up until 1990 CoalCorp North Island's accident record was six times that considered acceptable in those NSW operations with good accident prevention programmes. This was an obvious avoidable burden on the company in both human and cost terms.   Late in 1989 an accident prevention programme was implemented with the objective of achieving a 50 per cent reduction in the lost time accident frequency rate within 12 months. The key to achieving this objective was recognised as being an attitude change in the total workforce from General Manager downward. Management commitment and action were seen to be critical to the success of the programme.   Through very basic and simple training programmes in accident investigation, analysis and reporting, communication, on-the-job coaching and in focusing on improving supervision skills, the original objective was achieved.   During 1991 the application of methods improvement and hazard recognition techniques are seen as the logical step to achieving a further 50 per cent reduction in the accident frequency rate.

Jan 1, 1991

By A S. Leitch

This paper is based on the accident prevention pro-gram carried out in the coal mines of Alberta. It defines the role of the Alberta Mines Branch and of The Work-men's Compensation Board, and relates how a safety pro-gram was initiated. The formation of the Alberta Class 1 Mining Safety Council is also described. The responsibilities of both management and the individual worker are then outlined, and the main features of a successful accident prevention program are delineated. T HE purpose of this paper is not to repeat generalities and platitudes about industrial safety, but rather to relate the experience of Alberta coal mines during the past number of years in their efforts to keep accidents to a minimum. It has been learned from experience that many basic principles are as sound today as they were 20 years ago. How-ever the complexities of modern mining methods and the modern man or miner have created problems that did not exist then.

Jan 1, 1964

By Andrés Galarza Flores

En la minería metálica subterránea se desarrollan casos frecuentes de accidentes por gaseomiento a través del monóxido de carbono y los vapores nitrosos. En este sentido, el texto describe un programa de seguridad que comprende la higiene industrial, la composición de los gases nitrosos, su origen en la industria minera, los límites permisibles de los vapores nitrosos, el reconocimiento y evaluación de los gases nitrosos en las fuentes conocidas, los vapores nitrosos en el organismo humano, los casos de accidentes con vapores nitrosos y las medidas preventivas.

Nov 20, 1978