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By Marina Carreiro-Silva, Cátia Cardoso, Bruce Shillito, Lisa Mevenkamp, Alastair Brown, Maria J. Bebianno, Juliette Ravaux, Inês Martins, Nélia C. Mestre, S. Sousa Vânia

Mineral extraction activities in the deep sea will expose the local fauna to potentially toxic compounds. However, very few data are currently available on the complex ecotoxicological risks to deep-sea fauna from the potential release of heavy metals, trace metals and Rare Earth Elements (REEs). Nonetheless, this is key information essential to support the regulation of industrial activities in the deep sea. One of the fundamental issues that the MIDAS project will address consists in exploring the concept of whether the existing toxicity test protocols and limits established in shallow-water species are applicable to deep-sea mining. We will detail the specific challenges to recommending exposure limits within the deep sea and show preliminary results of comparative toxicity tests in the shallow-water and in the deep-sea environment.

Sep 1, 2014

By Brett Zernich, Michael Krulc, Brett Robinson

This paper provides an account of the efforts undertaken to construct the Northeast Interceptor Sewer (NEIS) project, which is a portion of a much larger program in Los Angeles, California to upgrade the city’s wastewater facilities. The project consisted of a number of elements, including both soft ground and rock slurry wall shafts, drilled shafts, soft ground EPBM mining, rock TBM mining, large diameter pipe placement, and underground structure construction. The need to complete the project under strict schedule constraints, in addition to the challenges of underground construction in congested urban areas, necessitated the work be undertaken with the proper balance of state of the art equipment, and thoughtful planning. The paper will detail the means, methods, and equipment used on the project, as well as discuss several of the unforeseen conditions encountered during construction.

Jan 1, 2005

By Peter B. Dowden, Robert A. Robinson

Boulders, frequently found in tunnels excavated through soils, can pose major problems for full face TBMs in terms of slowing or halting the tunnel advance, cutter damage, and abrasive wear. The paper aims to consider the problem as a whole, from the geological characteristics of boulder sites, to the appropriate physical design of theTBM, and its operation in boulder-laden soils. In addition, visualization of boulders and other subsurface obstructions by seismic methods and ground penetrating radar are reviewed. The paper will assist the construction planner in assessing the risks and preparing appropriate specifications.

Jan 1, 2001

By James J. Meadows, Jason D. Pampena, Emanuele G. Cauda, Lauren G. Chubb

Exposure to respirable crystalline silica (RCS) can cause serious and irreparable negative health effects, including silicosis and lung cancer. Workers in coal mines have the potential of being exposed to RCS found in dust generated by various mining processes. The silica content of respirable dust in one single mine can vary substantially over both time and location. The current monitoring approach for RCS relies on the use of traditional air sampling followed by laboratory analysis. Results generated using this approach are generally not available for several days to several weeks after sampling, and this delay prevents timely and effective intervention if needed. An alternate analytical method is needed to reduce the time required to quantify the RCS exposure of mine workers. The National Institute for Occupational Safety and Health (NIOSH) has developed a new method using commercially available portable infrared spectrometers for measuring RCS at the end of the sampling shift. This paper will describe the application of the new field-based RCS analytical process for coal mines, including the use of the new method with the existing Coal Mine Dust Personal Sampler Unit. In a case study conducted by NIOSH with a coal mine operator in West Virginia, field-based RCS analysis was completed at a mine site to evaluate the new technique. The RCS analysis results obtained by the field-based method in this case study showed sufficiently strong correlation with results obtained by the MSHA standard laboratory analysis method to allow the mine operator to use the field-based method for evaluating process improvements.

Ledcap Pty Ltd has developed two software tools for assisting in the determination of life-of-mine (LOM) trucking requirements. The first tool generates haul paths and the second calculates truck travel time over these paths. The two step approach allows the paths to be viewed and if required edited, to better represent the actual site haul routes.The first tool automatically creates haul paths between the mine bench and the dump. To do this the user supplies a master haul route and a scheduled block model. The master haul path and the block model are interacted to create multiple haul routes, one for each pit/dump bench pair in each scheduling period. Each path carries with it a record of the scheduling period it represents and the dry tonnage hauled over the path in that period.The second tool calculates truck travel time over the path. Data from the manufacturer's rimpull and retarder curves are used to calculate accelerations and speed over each segment of the haul path. As the paths are derived from digitised representations of mine haul routes the path f les often have over a hundred segments. This detailed representation of the haul route allows the software to automatically adjust speed for different radius corners and accurately simulates the changing accelerations over the gradient changes that occur in real life mine ramps. Rolling resistance can be specified at a global level, at a segment level and at a period level. This allows rolling resistance to be changed seasonally as well as spatially.Life-of-mine trucking studies attempt to calculate an accurate answer from extremely variable inputs. This paper will detail the features of the two software tools and how the tools provided in the software can assist the mine planner to have greater confidence in their life-of-mine trucking requirements and the subsequent production capacity inputs to their scheduling calculations.

Dec 6, 2010

By Gregory M. Molinda

Historically, miners have known that roof rocks originally composed largely of mud were prone to slaking and deterioration when exposed to water and humidity. Mine Safety and Health Administration (MSHA) records show that roof falls are more prevalent in summer and late fall. Field data shows higher bolt loads and increased room convergence in summer months. Laboratory data shows that very high internal pressures can be generated by significant strain in clay-rich rocks. In summer months humidities ranging from 70-100% can cause rock strains up to 7%, and rock pressures of 14,000 psi, more than enough to break apart weak shales and fireclays. The National Institute for Occupational Safety and Health (NIOSH) conducted wet/dry immersion cycling of clay-rich rocks. Results show that the rocks most prone to moisture deterioration are fireclays, claystones, and sandy shales, all of which have disrupted bedding. Of the 7 mudrocks with a weatherability index above 40%, none showed consistent fissile bedding. Black shales were surprisingly resistant to wet/dry water immersion cycling. Generally, mixed rocks (stackrock), typically susceptible to horizontal stress, are more resistant to moisture-deterioration. Mine roof rocks tested with moisture sensitivity ratings above 50% (moisture sensitivity index ranges from 0-100 with 100 being the most sensitive) all came from mines which had roof skin problems and used supplemental support to prevent rock fall injuries. Some roof rocks showed lateral variability of moisture sensitivity values, suggesting the need for more samples in highly varying roof rocks. Swelling strains of mudrocks showed that almost all of the swelling occurred in the first 24 hours after immersion. The wet/dry immersion cycling test used provides an accurate, quick and inexpensive method for estimating the moisture sensitivity of mudrocks. With this information mine operators can begin to anticipate hazardous ground and prepare appropriate roof support.

Jan 1, 2006

By M. Veiga

"Mining is an energy and water intensive activity. Increasing energy efficiency and reducing water consumption are two of the key requirements in moving toward a more sustainable mining industry. Water reduction, reuse and recycle options are reviewed, identifying cases where these options have been implemented. Then a novel mine water network design method is described, which analyzes a mine/mill water system in order to identify areas where water requirements and water system energy requirements can be reduced. First, a site water balance is determined and major water consumers and sources are specified. Next, multiple possible combinations of supplying water to mine and mill consumers are compared. Finally, low energy and water combinations are identified.INTRODUCTIONMining consumes vast quantities of energy: The whole mining and metals sector consumes over 12% of the world’s energy (DOE, 2009). Mining also requires large quantities of water, although mining water consumption is a relatively small portion of the overall world water use. Even in relatively dry, mining-intensive countries like Australia and South Africa, mine water consumption is only 2-3% of national water demand (Brown, 2003). However, at the local level, when mining takes place in areas where water is scarce, mine water consumption can severely impact local supplies. In addition, acid rock drainage, leaks from waste impoundments, or direct disposal of tailing into waterways can contaminate surface and groundwater (MMSD, 2002). Mine water systems can be large energy consumers, but better mine water systems can reduce both water and energy consumption. Improving water system design and practice are key strategic requirements in moving toward a more sustainable mining industry.This paper addresses conventional base-metal or precious-metal mine sites, which consist of an underground or open pit mine and a mineral processing plant, or mill. Ore is extracted and processed through the plant to produce a saleable product. Tailing, or waste material, is then deposited in a tailing storage facility (TSF). Any rock removed from the mine with no economic value, or waste rock, is stored without being processed."

Jan 1, 2010

Removal of Dilute Toxic Anions in Wastewater Using Aluminum Hydroxides Co-Precipitation Method

Sep 13, 2010

By Oliver Bowles

Accidental explosions in coal mines are due to various causes, but many of them can be directly attributed to coal dust; others that probably in no way depend on dust as a primary cause are propagated, greatly intensified, and made more disastrous by the presence of coal dust. The fact that coal dust in a bituminous mine will explode as a result of a fire-damp explosion has been generally accepted for many years, but the belief has also been held by many that coal dust is not in itself dangerous when unmixed with an explosive gas. Therefore, in past years little attention was given to dust in mines free from fire damp, and many disastrous explosions have resulted from lack of knowledge of the danger from coal dust. In the explosives gallery and experimental mine of the Bureau of Mines experiment station, Pittsburgh, Pa., it has been proved repeatedly and conclusively that coal dust will explode violently when no inflammable gas is present. PROPAGATION OF DUST EXPLOSIONS A coal-dust explosion is an extremely rapid burning or combustion of the coal particles. Their burning consists essentially of the combination of the hydrocarbons in the coal with the oxygen of the air, a process that generates heat and flame and produces hot gases and water vapor. These gases and vapors have a volume many times that of the original coal particles; thus they exert an outward motion and pressure which constitute the explosive wave. When fine particles of coal are suspended in the air, each particle is surrounded by the oxygen of the air, and thus is well placed to oxidize or burn rapidly whenever the temperature is high enough. If some particles are ignited from any cause they will fire others, and the combustion will extend from particle to particle with extreme rapidity wherever enough coal dust of sufficient purity is present.

Jan 1, 1925

By C. W. Siyasiya, K. A. Annan, W. E. Stumpf

"SynopsisThe relationship between niobium content and austenite grain growth has been investigated through hot rolling simulation on a Bähr dilatometer. The effect of delay time between passes during rough rolling in Nbmicroalloyed steels with nitrogen contents typical for electric arc furnace (EAF) melting was studied. The results indicate that the grain growth constants n, Q, and A increase with an increase in Nb content. The activation energy for austenite grain growth Q was found to be in the range of 239 to 572 kJ/mol, the exponential constant n ranged from 2.8 to 6.2, and the material and processing condition constant A from 4.24 × 1012 to 4.96 × 1028, for steels with niobium contents ranging from 0.002% Nb to 0.1% Nb. A general constitutive equation for the prediction of austenite grain growth in these Nb-microalloyed steels under rough rolling conditions has been developed. Good agreement between the experimental and the predicted values was achieved with this constitutive equation.IntroductionGrain refinement has been found to increase both the strength and toughness of steels (Gao and Baker, 1998; Sharma, Lakshmanan, and Kirkaldy, 1984; Seok et al., 2014; Maalekian et al., 2012). It is also known that the austenite grain size directly influences the microstructure, and thus the mechanical properties, of the steel (Maalekian et al., 2012; Yue et al., 2010). Effective grain growth control is reported to be achieved through addition of precipitate-forming elements, such as Nb that, slow down the grain boundary migration through pinning and solute drag mechanisms (Yu et al., 2010; Olasolo et al., 2011; Alogab et al., 2007). Much work has been carried out on austenite grain lsize control by the addition of precipitate-forming elements that have a strong affinity for interstitial elements, such as carbon and nitrogen, which form the dispersed pinning particles to inhibit the austenite grain growth (Alogab et al. 2007; Hodgson and Gibbs, 1992; Nanba et al., 2003; Flores and Martinez, 1997; Rollett, Srolovitz and Anderson, 1989). Austenite grain growth can be described using a conventional or a modelling approach. With conventional approaches (e.g. metallography), in-situ monitoring of austenite grain growth at high temperatures is impossible. Modelling the grain growth behaviour based on available data is the ideal option. To quantitatively describe austenite grain growth therefore requires development of a sound mathematical austenite grain growth equation that accounts for the effects of the varying microalloying elements in inhibiting austenite grain growth. Numerous attempts have been made to develop an empirical model based on the general equation developed by Sellars and Whiteman (1979). Many of these models do not account for the direct effects of the microalloying elements such as Nb in austenite grain growth control [Fu et al., 2011; Wang and Wang, 2008; Wang et al., 2006; Shanmugama et al., 2005; Banerjee et al., 2010; Pous-Romeroa et al., 2013). The current work has considered this limitation, taking into account the direct effect of niobium in grain growth control during thermal processing. This is done by incorporating the initial austenite grain size Do and the microalloying element niobium in the development of a constitutive equation for grain growth prediction in Nb-containing microalloyed steels."

Jan 1, 2015

By P Brown, M Nagarajan, A Green, P Dare-Bryan

Coal loss is an important issue at many coalmines, with losses of five per cent being common. The type of loss varies from mine to mine but is dependent on mine strata, the drilling and blasting processes applied and the mining method used. Typical coal loss mechanisms from the drill and blast process are coal roof damage and edge loss. Usually a reduction in coal loss is in direct competition with the need to provide material that is well-fragmented and a muck pile that has the required cast percentage. These competing issues were addressed over a two-year period at a mine in the New South Wales Coalfields by implementing a five-step approach. This was centred around building an understanding of the coal loss mechanisms utilising proprietary heave- modelling software, measuring coal losses by comparing survey to drill and/or gamma logs and implementing appropriate coal loss reduction processes. The end result exceeded expectations with a 95 per cent reduction in coal loss. Mine excavation productivity was maintained and coal loss minimised to less than one per cent of the in situ coal block.CITATION:Nagarajan, M, Green, A, Brown, P and Dare-Bryan, P, 2015. Managing coal loss using blast models and field measurement, in Proceedings 11th International Symposium on Rock Fragmentation by Blasting, pp 429–436 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 24, 2015

The Kalgoorlie Tailings Retreatment Project (or "Kaltails") involves the reclamation and retreatment of approximately 50 million tonnes of gold tailing situated on the Golden Mile at Kalgoorlie, Western Australia. Tailing is reclaimed and retreated at the rate of 42 million tonnes per annum. The project is a Joint Venture between Poseidon Limited and Gold Corporation, with Poseidon being the major participant (90%) and manager of the operation through its wholly owned subsidiary Kaltails Mining Services Pty Ltd. The marginal nature of the tailing retreatment project dictated that a detailed feasibility study be undertaken. Extensive sampling and metallurgical testing of the tailing permitted the development of an optimum economic processing route. A sensitivity analysis undertaken as part of the feasibility study indicated the project to be very sensitive to gold price and unit operating cost variations, and relatively insensitive to capital cost variations.

Jan 1, 1990

This paper describes a mobile laboratory developed specifically for nickel prospecting, and which was designed to be operated by sub-professional staff in remote areas independently of established laboratories. An atomic absorption spectrophotometric procedure was used to determine nickel, cobalt, lead, zinc, and copper ID latentIc and sulphIde samples, with a detection limit better than 25 µg/g for all elements. The procedure was applicable to both soil and drill samples and the accuracy of the procedure, which was ±5 per cent relative at the 1,000 µg/g level was sufficient for the preliminary assessment of mineralized samples and the control of drilling operations. The analytical procedure and the means taken to ensure the necessary reproductibility and accuracy are described. One operator can carry out 400 elemental determinations per 8-hr day at an approximate cdst of 6 cents per elemental determination. The results are returned within a single day, a factor which can contribute materially to the efficiency of drilling operations.

Jan 1, 1970

By Thomas M. Nasiatka

Tests with a high-pressure water jet were conducted in the steeply pitching Roslyn No. 5 bituminous coalbed in the Roslyn No. 9 mine, Roslyn, Wash., to determine the feasibility of extracting coal from pillars and from a solid coal face in development without drilling and blasting. During pillar mining, using a hand-held monitor, the best results were obtained with a 0.150-inch- diameter nozzle, a water pressure of 3,500 psi, and a flow rate of 38.5 gpm.3 The rate of mining and productivity were 0.74 ton per minute and 16.6 tons per man-shift, respectively. During development mining, using a monitor mounted on a roof jack, the best results were obtained with a 0.148-inch-diameter nozzle, a water pressure of 4,500 psi, and a flow rate of 40.0 gpm. In one section of the mine where the coal was relatively hard, the rate .of mining and productivity were 0.10 ton per minute and 5.7 tons per man-shift, respectively in another section of the mine where the coal was relatively soft, the rate of mining and productivity were 0.51 ton per minute and 8.3 tons per man-shift, respectively. The tests showed that hydraulic mining methods were more productive than conventional mining methods in pillar mining. In development the productivity of hydraulic mining depended primarily upon the coal hardness. Compared with conventional methods, hydraulic mining methods were less productive where the coal was relatively hard and equally as productive where the coal was relatively soft.

Jan 1, 1963

By H. J. Chalmers

THE H.B. MINE and concentrator are located in the Nelson Mining Division of British Columbia, on the north side of the Sheep Creek valley about seven miles southeast of the town of Salmo. It is an operation of The Consolidated Mining and Smelting Company of Canada, Limited (Cominco), which has its metallurgical plants at Trail, about 25 miles west. The property was originally staked about 1907 by Horton and Benson, whose names are commemorated in the designation "H. B." Up until 1927, a considerable amount of development work was done in the upper levels by various companies. Cominco purchased the ?property in 1927 and carried out intermittent work until 1946. Following this, an extensive surface diamond drilling programme and a subsequent underground exploration were undertaken. Sufficient ore was outlined 'to warrant the construction of a 1,000: ton concentrator. This was started in April, 1952, and completed by the spring of 1953. However, because of adverse base metal market conditions, operation was deferred until May, 1955.

Jan 1, 1957

Innovative Technology for Optimised Thickening Sedimentation

Sep 13, 2010

By J. M. Mutmansky, L. Xu

"IntroductionSince the establishment of the star,just concentration of 2 mg/m3, a strong effort has made by mining engineers and researchers to provide better dust control equipment and procedures for underground coal mines.Particular areas of success have been implementation of better coal-cutting strategy to control dust generation, better design of water sprays for dust suppression and air movement, use of scrubbers, and improved design of face ventilation systems. A drastic improvement occurred over time such that the average dust concentrations for continuous miner operators dropped from 6.5 mg/m3 in 1968 to 1.3 mg/m3 in 1980 and for auger, cutter, longwall, and roof bolter occupations from 2.7 mg/m3 in 1973 to 1.6 mg/m3 in 1980 (Niewiadomski, 1983).While dust concentrations in mining sections have been dropping considerably, one problem area has been mining sections where quartz is a considerable portion of the airborne dust. The federal regulations require that quartz content must be held below 0.1 mg/m3 in the air regardless of the concentration of the total dust. This legislation limits the allowable dust concentration to a ""reduced standard"" of 10/ (% quartz) when the quartz content of respirable dust in the mine atmosphere is more than 5%. Today, approximately one-third of underground coal mining operations have designated areas with more stringent dust standards in place, and many mines experience considerable difficulty in meeting these standards (Jankowski, and Babbitt, 1989).It is well known that metal miners subjected to respirable dusts high in quartz have a higher incidence of silicosis than those exposed to dust low in quartz. However, the role of quartz in the development of coal workers' pneumoconiosis is still a highly controversial question, in spite of the large number of research projects devoted to this subject over the last 20 years. Because coal seams contain less quartz than metal ores and quartz often comes from sources outside the coal seam (e.g., roof and floor), it is difficult to relate studies that deal with the quartz content in coal seams and the incidence of coal workers' pneumoconiosis. Hamilton, Ogden, and Vincent (1983) have provided a plausible explanation for the incidence of the disease by hypothesizing that the quartz content does not affect the probability of developing pneumoconiosis until some threshold value (generally thought to be about 10%) is exceeded.The objective of the research studies summarized here was to obtain a better understanding of quartz occurrences in airborne coal mine dust by studying the variations of the quartz levels in different dust sizes and the relationship between the quartz content in airborne coal mine dust and the quartz content in the mined material. The implications of the results to control of dust in high-quartz sections will also be discussed."

Mar 1, 1992

By A. T. Visser

"SynopsisAlmost 20 years have passed since the cutting-edge research by Thompson and Visser on the design and management of opencast mine haul roads was conducted in South Africa. This system is based on three principles, namely the structural ability to support the ultra-heavy truck loads, the selection of vehicle and environmentally friendly riding surface, and an appropriate level of maintenance to counteract wear and tear. Obviously, proper layout and geometry are essential.These principles have been implemented worldwide, and it is useful to review the lessons learned. The objectives of this paper are to present a critical review of the status of mine haul road design and management, and the impact that these principles have made on operations, particularly the cost-effectiveness. The paper briefly reviews the principles of the haul road design and management and the extent to which they are applicable. Case studies of a number of implementations are presented to demonstrate that the principles are sound and have been applied effectively. For example, at an international operation the transport cost of coal was 40% more expensive than anticipated in the feasibility stage, and this made the mining operation uneconomic. Correction of this problem resulted in a viable enterprise. Although designed for opencast operations, the principles are equally valid for underground operations, and initial development work will be discussed.The main conclusions are that the research approach is valid and its effectiveness has been demonstrated in a number of applications. The anticipated financial benefit has been derived, and has made the mining operations that used the principles more effective. Of major importance is the application of opencast haul road design principles to the future thrust of using driverless vehicles in opencast and underground mining, where the road quality is not negotiable as there is no driver that can avoid obstacles or severe road deterioration.IntroductionAlmost 20 years have passed since the cutting-edge research by Thompson and Visser on the design and management of opencast mine haul roads in South Africa (Thompson and Visser, 1996a, 1996b, 1998, 1999, 2000a). This system is based on three principles, namely the structural ability to support the ultra-heavy truck loads, the selection of vehicle and environmentally friendly riding surface, and an appropriate level of maintenance to counteract wear and tear. Obviously, proper layout and geometry are essential."

Jan 1, 2015

By Kenneth M. Maas

The Bureau of Mines inventoried all lands in Alaska to determine the availability of land for oil, gas, and coal leasing. Acreage for onshore oil, gas, and coal basins was digitized as was land ownership data. Regulatory policy concerning oil, gas, and coal leasing for various government agencies and private concerns was determined. Oil and gas basins underlie 79.4 million acres of Alaska's 378 million acre landbase. Federal agencies manage 44 million of these acres. The Bureau of Land Management is the lead agency for most oil and gas leasing on Federal lands. Lands have to be specifically opened for oil and gas leasing to be available. The state of Alaska manages 21.1 million acres underlain by these basins. More than 80 percent of this acreage is available for resource development. Native corporations manage the remaining 14.3 million acres of favorable oil and gas land. Coal basins underlie nearly 51 million acres of Alaska. Of this land, 26.4 million acres are under Federal jurisdiction. The state manages 17.3 million acres of land underlain by coal basins. Nearly 7.3 million acres of favorable coal lands are managed by Native corporations.

Jan 1, 1991

By Tristan Worsey, Nathan Rouse

Florida legislature allocated funding for the Florida State Fire Marshal to review the applicability of the United States Bureau of Mines (USBM) Report of Investigations (RI) 8507 blast vibration limits with respect to Florida and its soils. The study also discusses whether the current blasting vibration limits set by statute are still appropriate, including a review of measured vibration amplitudes and frequencies, structure responses, and theoretical analyses of material strength and strains.

Jan 1, 2019