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By John Haviland, Richard E. Danell

"BHP Australia Coat Pty Ltd (BHPAC) operates seven large open pit coal mines in the Bowen Basin ofCentral Queensland, Australia. These mines have operated for periods ranging from 16 to 37 years. All of these mines have dipping seams to varying degrees and are facing increasing overburden removal in an effort to maintain production. To ensure the economic viability of the operations, this increased level of overburden removal must ah.0 be conducted at lower unit costs."

Jan 1, 1995

A New Online Detection Method for Arsenic Minerals in Process Streams

Sep 13, 2010

By Yanjie Liang

Elemental sulfur and volatilization kiln slag(VKS)containing heavy-metal produced by smelter factories were used to produce sulfured building material. The effects of heating mode, material proportion (MSulfur:MVKS), size of waste particles and ratio of aggregate to filler(A/F) on the mechanical properties and leaching toxicities of solidified stuff were investigated. The optimal conditions for the solidification are stepped heating mode, 3:7 ratio of MSulfur to MVKS, particle size less than 150µm and 3/17 ratio of A/F. Under the above optimal conditions, the compressive strength of solidified stuff rises to 35 MPa, and water absorption is down to 4%-6%.Furthermore, when NaOH is applied as an additive in the process of solidification, the 2+concentrations of most heavy metals except Pb have reached the national leaching toxicity standard. The results of X-ray diffraction reveal that sulfured solidification is caused by the physical encapsulation rather than chemical transformation.

Jan 1, 2010

By Liping Yu Che, Xiaotie Wang, Mingli Cao, Jizu Yongfu Yuan

"It is difficult separating fluorite from Ca, Ba, Si intergrowth minerals than simple from Si, using common reagents such as combination of oleic acid or paraffin soap and water glass, but the finest quality fluorite concentrate whose grade is over 96%F must be required in chemical plant.This paper studies the flotation process of native fluorite from calcite, barite and silicate minerals whose flotation properties is similar to fluorite, using new effective collector H602 and new depressor S602 that is cheaper in cost, and describes the flotation properties. In order to determine optimum flotation separation condition, the effect of pulp pH, pulp temperature, pulp density and the effect of dosage of reagents on flotation were investigated and the flotation result was provided by oleic acid collector and the results of collector H602 were compared with those of collector oleic acid in the test. The test result of ore samples shows that at moderate pulp pH values (10.5-11.5) and other moderate technical conditions, the fluorite mineral can be obtained by new reagents and the rational reagents combination. The conclusion is 98%F of fluorite concentrate can be obtained, using the combination of H602 and S602 and only 5 steps in techniques. The paper discusses the mechanism of the flotation separation of fluorite mineral from intergrowth minerals."

Jan 1, 2003

By Clay Haynes

While the Kansas River Tunnel is a relatively short, small diameter tunnel, the shaft excavation methods implemented were long and large on innovation and use of reverse circulation drilling equipment. ATS Drilling, L.P. used mechanical excavation techniques for both soil and rock segments of the 42.7 m (140 feet) and 38.1 m (125 feet) deep shafts that were 2.9 m (9.5 feet) and 4.1m (13.5 feet) diameter, respectively.

By Y. Z. Xu

This paper presents a new dynamic method called Resonant Pile Test (HPT) for evaluating bearing capacity of pile. The basic conception of RPT is given in brief and the measuring system is also introduced. In addition, the influences of the magnitude of exciting force and of the mass of pile cap on test results are discussed. Finally, comparisons between values of bearing capacity given by RPT and by static load tests for a variety of pile types are listed.

Jan 1, 2010

By Claus Goetzel

THE object of this investigation was to determine whether silver alloys could be used instead of the currently employed insert of high-expansion AVERAGE COEFFICIENT PER DE G. C. OVEN RANGE 20° To 200° C. Pure aluminum '31.6 X 10-6 Cast low-expansion Si-Cu-Ni-Al piston alloy 20.0 X 10-6 High-expansion austenitic Cu-Ni cast iron 19.3 X 10-6 Cast steel (0.25-0.35 C, 0.10-1.0 Mn) 12.6 X 10-6 Cast iron (3.15 total C, 2.16 Si) 12.8 X 10-6 Pure silver 18.9 X 10-6 austenitic ferronickel alloy, to reduce the wear of ring grooves in light metal pistons. A typical example of a piston containing a ferronickel insert is shown in Fig. 1. The high coefficient of expansion of silver made it worthy of consideration, while the small size of the insert would render it use feasible in Germany as an emergency in is- tire. The coefficients of linear expansion of several metals and alloys are as shown in the table above. Obviously the melting point of the insert must be high enough to prevent it from melting when the light alloy is cast around it. This imposes a lower limit of about 850° C. for the solidus of the silver alloy. Pure silver melts at about 961° C., so that the Fin. 1.-PISTON CONTAINING tolerable depression in the solidus is rather FERRONICKEL INSERT. small. To avoid deformation of the insert during use a Brinell hardness number of at least 60 appears necessary.

Jan 1, 1937

By F. -J. Wodopia

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

Jan 1, 2011

The status and outlook for mining, in your view. Minerals remain a major part of the world’s economic foundation. The fortunes of the mining industry rise and fall with general economic trends, but mining is no less important today on a global basis than it has been historically. Certainly, portions of the industry are critically depressed — domestic copper to name one area —but other sectors are prospering. Mineral consumption, both worldwide and in the United States, has increased steadily since the Great Depression, hitting all-time highs in 2000, the last year for which I have seen data. The highly developed economy in the United States tends to obscure the continuing importance of minerals here. But in less developed nations the critical nature of minerals is obvious and well accepted. In short, although there is no shortage of problems or challenges facing mining — there never has been — mining remains an essential business with great global opportunity.

Jan 1, 2003

By Dale S. Preece, Stephen H. Chung

Explosives energy can be used effectively in breaking and displacing large volumes of rock in mining and quarrying industries in both open pit and underground. The blast result, however, may not be economical if the applied explosives energy distribution is not properly applied to match a given set of geometries. However, this engineering problem can be resolved by using a modeling approach in the blast design process. Starting with a given set of blast design parameters that include explosive, elastic properties of rock, geometry of the blast pattern as well as the delay firing time, this paper shows how a discrete element blast model can be set up to allow the examination of the effect of critical design input parameters on blast results. Examples are given in this paper to help visualize the value and application of blast simulations. They are (1) regular and terrace bench blasting models for throw control, (2) underground blasting including a drop raise opening and (3) collapsing of a multiple room-pillar structure with proper firing sequence to control the mixing of blasted materials.

Jan 1, 2005

By D Beahm

Introduction The Energy Metals Corporation (EMC) holds numerous mineral properties in the northern portion of the Great Divide Basin including the JAB Property, one of several potential properties being planned for development as a satellite facility to the greater Antelope Uranium Project. A National Instrument 43-101 Technical Report has been completed for the JAB property. This report estimates total measured and indicated mineral resources on the property totaling 3,555,022 pounds U3O8 contained in 2,400,875 tons at an average grade of 0.073 % U3O8 at a .25 GT cutoff in accordance with CIM Standards on Mineral Resources and Reserves. The JAB Property is located in Sections 13, 14, 15, 16, 21, 22, and 23, Township 26 North, Range 94 West, approximately Latitude 42o 14’ North and Longitude 108o 00’ West (Figure 1, Location Map). This property consists of unpatented mining lode claims and Wyoming State mineral leases comprising approximately 2,100 acres.

Jan 1, 2007

By R. G. Gürtunca

Over the past century coal miner safety and health has seen tremendous improvements, the fatality and injury rates continue to decrease while productivity continues to increase. Many of the hazards that plagued miners in the past, such as coal bumps, methane and coal dust explosions, ground fall accidents and health issues have been significantly reduced. The contribution of NIOSH research includes products for prevention and survival of mine fires, methane control measures, design procedure for underground coal mines, methods for excavation surface controls, methods and procedures for blasting, laser usage in underground mines and prevention of electrocution from overhead power lines that have reduced accidents and injuries in underground coal mines. Health research has produced products such as the personal dust monitor, noise abating technologies and ergonomic solutions for equipment operators. Research priorities at NIOSH are set by considering surveillance statistics, stakeholder inputs and loss control principles. Future research in coal mining is directed towards respiratory diseases, noise induced hearing loss, repetitive musculoskeletal injuries, traumatic injuries, falls of ground and mine disasters. The recent spate of accidents in coal mines resulted in the Miner Act of 2006 which includes a specific role for NIOSH in future mine safety research and development. The mine safety achievements in the USA reflect the commitment of industry, labour, government and research organizations to improving the safety of the mine worker.

By Mario Morin

The application of underground pre-concentration technology to narrow vein mining has the potential to change the entire economics of bulk mining methods when used in narrow vein situations. The rejection of waste at or near the face means that a higher-grade ore can be sent to surface. The waste rock can be reused directly as backfill. Swelling of the muck through blasting means that only 60 to 65% can be used as fill. Planning and scheduling of the fill usage is key to the success of this method. Through the use of simulation and system analysis, this paper examines the planning and scheduling implications of underground pre-concentration when applied to traditional narrow vein mining methods (cut-and-fill /drift-and-fill, longhole, AVOCA). It considers the logistical factors that represent potential system bottlenecks that are key to understanding the correct implementation and control strategies.

Oct 1, 2004

By Mike Higgins

"Data management is emerging as a major concern for miners. Engineers today are faced with anextensive array of data from varying sources, and are required to consolidate and analyse thisinformation to produce an effective and efficient mine plan. The viability of a mining operation canbe dependent on the outcomes of this process. With so much at stake, it is no surprise that mostengineers prefer a standard approach to blasting which is designed to minimise risk rather thanoptimise performance."

Jan 1, 1998

By Mandy Korff

Walls consisting of CFA-piles are often used for vertical cut offs for building pits. Several methods of installation and geometry may be used and sizes, depths and strengths of walls necessary vary widely. Based on experience with secant CFA-pile walls in The Netherlands, requirements for this type of wall can be set with a risk management view to it. This paper describes those requirements, based on specific local conditions.

Jan 1, 2006

By Alexander B. Reeb, Richard J. Varuso, George M. Filz, Jehu B. Johnson

"T-walls, which are concrete floodwalls in an inverted “T” shape, are an integral component of the Greater New Orleans Hurricane and Storm Damage Risk Reduction System (HSDRRS). In order to resist large lateral flood loads, T-walls are typically supported on long batter piles that extend through the weak and compressible clays and peats commonly encountered in southern Louisiana. Since the piles are battered, settlement of the compressible foundation soils can result in loads acting normal to the piles and induce pile bending moments. Therefore, the design of pile-supported T-walls is a complex soil-structure interaction problem that requires detailed and careful numerical analysis to accurately estimate the stresses and bending moments in the piles. For this paper, numerical analyses were performed for three cross sections that each included a two-pile T wall system that was installed within a 15-ft tall new levee embankment. The cross sections were identical except that the elevation of the T-wall base was varied. This paper discusses the analyses, and it compares the influence of settlements and flood loading on the pile stresses and bending moments. In addition, this paper includes general recommendations for the analysis and design of pile-supported T-walls in practice.INTRODUCTION AND BACKGROUNDThe recently completed Greater New Orleans Hurricane and Storm Damage Risk Reduction System (HSDRRS) includes 350 miles of levees and floodwalls and is designed to defend against a 100-year storm surge event. The floodwalls predominantly consist of I-walls and T-walls. I-walls are comprised of a sheet pile wall curtain capped with a monolithic concrete wall above grade. T-walls are similar to I-walls, but they include a wide concrete base at grade, which forms an inverted “T” shape, and they are generally supported by long batter piles that provide additional lateral and rotational stability for resisting flood loads.During Hurricane Katrina, several I-walls failed, resulting in large breaches and devastating flooding (Duncan et al. 2008, IPET 2009). T-walls on the other hand performed quite well, including T-walls that were overtopped and eroded on the protected side, yet still did not collapse. As part of the HSDRSS, more conservative designs and height restrictions were required for I-walls (USACE 2011), and a number of I-wall sections were replaced with T-walls. However, the design of pile-supported T-walls is complex and requires careful consideration of both flood loading and settlements."

Jan 1, 2017

By Cristian Rodriguez, Tom BoBo, Maria Rocha, John Kemeny

Blast fragmentation depends on many factors. First of all, it depends on the specific blast design, which includes the amount and type of explosive, the blasting pattern, the timing and sequencing, and other parameters. Secondly, it depends on the properties of the rock mass, including the uniaxial compressive strength (UCS), the rock mass elastic modulus (E), the rock discontinuity characteristics (as reflected in the GSI or RMR), and the rock density. Several fragmentation models have been proposed to predict blast fragmentation based on the blast design and the properties of the rock. These models include the Kuz-Ram model and variations of this model, as well as recent models by Kim and Kemeny (2011) and others. Fragmentation models are validated and calibrated by comparing the predicted fragmentation with actual post-blast fragmentation from image processing monitoring systems.

Jan 1, 2014

By William R. Yernberg

Santa Fe Pacific Gold, headquartered in Albuquerque, NM is expanding its operation at the Twin Creeks Mine in Nevada. The $250-million sulfide expansion project, including the Sage Mill, is under construction and is 80% complete. Also, additional mining equipment has been purchased to haul the sulfide ore to the mill. With the expansion, employment at Twin Creeks is expected to reach approximately 970 people by the end of 1996. Santa Fe Pacific Gold now owns and operates three gold mines in the United States and is involved in several other gold projects. The three currently operating mines are the Twin Creeks, Mesquite and Lone Tree mines. The Mesquite Mine is located in California’s Imperial Valley. Lone Tree is located 55 km (34 miles) southeast of Winnemucca, NV. The company’s total gold production from these operations is expected to be in the range of 26.3 to 26.6 t (845,000 to 855,000 oz) in 1996. This compares to a total production of about 124 kg (4,000 oz) for the company in 1989. Production costs range from $6.90to $7.25/g ($215 to $225/oz). At the end of 1995, the company reported proven and probable reserves of 556.7 t(17.9 million oz) of gold.

Jan 1, 1996

Low Zinc Prices Close Alcoa Mine Alcoa Mining Co., announced that it will suspend operations at its Hutson mine, near Salem, Ky., because of low zinc prices, January 15. The Aluminum Co. of America subsidiary announced that the low market has made zinc mining un- profitable. About 70 men were employed at the mine, with a production of about 5000 tons of zinc annually. Alcoa said the shutdown would not affect other company operations, with most of the men at Hutson absorbed in the mining firm's fluorspar operations in the same area.

Jan 2, 1953

The MINER Act of 2006 mandated that all underground coal mines must install and maintain refuge chambers. Refuge chambers serve as a temporary shelter in case of emergency. Several factors affect the performance of a refuge chamber: heat production inside the chamber and introduction of CO when chamber doors are opened are two major factors. This study examines the CO purging process and to determine total air quantity and time necessary to lower the CO con-centration to safe levels for different inlet/outlet configurations using three-dimensional simulation technique. The study uses Reynolds Averaged Navier Stokes and continuity equations along with the spe-cies transport model assuming uniform air mixing. The heat transfer of any kind is neglected and the purging process is assumed to take place isothermally. The standard k-e model is utilized for simulating turbulence in the flow field. This research provides useful guidelines in developing an efficient strategy for purging refuge chamber. Keywords: Airlock chamber, Purging, Carbon monoxide, Turbulence

Feb 27, 2013