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By D. Bradbury

Sufco coal mine, a subsidiary of Arch Western Bituminous Group, recently purchased a reverse osmosis (RO) system. The systems intent was to remove impurities in the water being mixed with the hydraulic oil to maintain the viability of critical longwall hydraulic systems and to prevent degradation. This project not only ensured hydraulic components from corrosion, but also revealed a cost savings by reducing the percentage of hydraulic oil mixed with the RO water. SUFCO WATER TREATMENT HISTORY Sufco coal mine has been in operation for approximately 70 years. Old works extend up to 15 miles one way, not including adjacent mined out longwall panels. Due to the geologic conditions and strata, water treatment has been as simple as putting water in at a high point of a mined out area and recovering it at a low point to discharge. Doing this reduces the total suspended solids (TSS) to less than 25 parts per million (ppm) and the total dissolved solids (TDS) less than 1,200 ppm which complies with Sufco?s water discharge permit. Even though the requirements for the permit were met, the water is still corrosive in nature. A portion of this water is piped back into the fireline (makeup) water system. It is then boosted to pressures of up to 500 psi to support mining sections, belt systems, equipment, fire fighting systems and the longwall.

Jan 1, 2011

By S. K. Oraee

Most management decisions at all levels of the organization are as directly or indirectly depends on the circumstance of future. With regard to predict the future events in the process of decision-making plays a main role, therefore, forecasting is very important for every organizations and institutions. There is a variety of methods to predict time series. In general, these techniques can be divided as following: statistical, artificial intelligence and analytical techniques. Two of the most common methods for time series prediction is autoregressive integrated moving average (ARIMA) and artificial neural network (ANN) methods, these methods are the subset of statistical and artificial intelligence techniques respectively. In this paper, a hybrid model of ARIMA and ANN models are employed to predict the number of fatal injuries in the USA underground coal mines. This research showed the result of hybrid model is better than split model.

Jan 1, 2011

By D. F. Malan

This paper gives an overview of the difficulties associated with determining the strength of hard-rock pillars. Although a number of pillar design tools are available, pillar collapses still occur. Recent examples of large-scale pillar collapses in South Africa suggest that these were caused by weak partings that traversed the pillars. Currently two different methods are used to determine the strength of pillars, namely, empirical equations derived from back analyses of failed and stable cases, and numerical modelling tools using appropriate failure criteria. The paper illustrates that both techniques have their limitations and additional work is required to obtain a better understanding of pillar strength. Empirical methods based on observations of pillar behaviour in a given geotechnical setting are popular and easy to use, but care should be exercised that the results are not inappropriately extrapolated beyond the environment in which they are established. An example is the Hedley and Grant formula (derived for the Canadian uranium mines), which has been used for many years in the South African platinum and chrome mines (albeit with some adaptation of the K-value). Very few collapses have been reported in South Africa for layouts designed using this formula, suggesting that in some cases it might yield estimates of pillar strength that are too conservative. As an alternative, some engineers strongly advocate the use of numerical techniques to determine pillar strength. A close examination unfortunately reveals that these techniques also rely on many assumptions. An area where numerical modelling is invaluable, however, is in determining pillar stresses accurately and for studying specific pillar failure mechanisms, such as the influence of weak partings on pillar strength. In conclusion, it appears that neither empirical techniques nor numerical modelling can be used solely to provide a solid basis for conducting pillar design. It is therefore recommended that both these techniques should be utilized to obtain the best possible insight into a given design problem. Owing to the uncertainties regarding pillar strength and loading stiffness, monitoring in trial mining sections and in established mining areas is also an essential tool to test the stability of pillar layouts in particular geotechnical areas.

Jan 1, 2011

By A. Duerksen

"Surface coal mining in West Virginia has supplied energy to the eastern coast of the United States for over a century. Over the years, the coal mining industry has been forced to adapt as societal demands regarding health, safety, and environmental impacts have changed. More recent pressure has called for another iteration of change: long-term post-mining sustainability. The research discussed in this paper investigates one potential solution - or component of a solution - to improve the sustainability of surface coal mining in West Virginia: post-mining wind power. The paper begins with an introduction to the Appalachian region of the U.S. and the role that mining has played in its history, followed by a discussion of the need for sustainable mining and how post-mining wind power may help fulfill it. Data processing methodology of field data from monitoring locations is then explained. The results are then used to estimate the electrical output of a wind turbine. This data is then utilized in a case study discussion of one of the monitored sites. The paper concludes with an analysis of the broader implications of the research and a discussion of future work."

Jan 1, 2011

By J. Talja

Keywords: drying, steam drying, concentrates, copper, lead During the past twenty years steam drying has become a prominent technology for drying of non-ferrous metals concentrate. This is mainly because of its low energy consumption and very low emissions. The first applications of significant capacity were stationary steam dryers, which however, faced severe challenges in maintenance costs and availability. That technology was soon replaced by Kumera?s rotary steam drying technology, which has been the dominant technology in new dryer installations world-wide for the past ten years, ever since the first installation in Hamburg in 1999. There are ten Kumera steam dryers in operation today and five more to be commissioned during 2011. Practically every dryer is different owing to continuous development, new innovations and operational experience with continuous feedback from the operators. Most significant improvements relate to capacity increase with the Kumera steam-dryer family, new feeder systems at the wet end, a completely new design of the dry material discharge with increased availability, heating element design and material selection, and control systems. This paper discusses the modifications and improvements introduced which have enabled the Kumera steam dryer to become the global leader in new dryer installations.

Jan 1, 2011

By I. T. Oramah

Despite the abundance of solid mineral deposits, Nigeria only earns about 0.5-1% of its current Gross Domestic Product (GDP) from the solid minerals sector. This is as a result of the dominance of the oil and gas industry, which has negatively affected the competitiveness of other sectors of Nigeria’s economy. The dominance of this industry has resulted in unemployment, poverty, hunger, domestic price inflation, corruption, unstable government, and higher exchange rates. These impacts are typical for economies suffering from the effects of "Dutch Disease" and the "Resource Curse". Community-based small-scale mining offers hope as an economic activity that can create wealth, employment, reduce hunger and poverty, and provide basic amenities for rural communities with solid minerals endowment. This study presents preliminary results of ongoing research into the prospects of using community-based small-scale mining in a developing country like Nigeria to move towards rural sustainable development.

Jan 1, 2011

By L. Lipsett

"Human rights can contribute to sustainability in the mining sector, both in theory and in practice. Both human rights and sustainability share a common concern to improve economic prosperity, environmental health and social equity by avoiding negative impacts and conflict, as well as by engaging with and empowering affected communities. Globally, there is an emerging consensus that companies have a responsibility to respect international human rights standards. Respecting human rights means that mining companies are responsible to ""do no harm"" to the people and communities affected by their operations. After a discussion of the Protect, Respect and Remedy framework for business and human rights, this paper illustrates some examples of how international standards for human rights and sustainability interacted in a recent assessment of Goldcorp's Marlin Mine in the Western Highlands of Guatemala. The final section explores how human rights should be integrated into broader policies and procedures for corporate sustainability. This includes integrating human rights into ESIA processes, legal compliance, corporate governance and grievance mechanisms. Pressures on mining companies to respect human rights will not disappear; therefore, a proactive and integrated approach to human rights is a fundamental component of a broader strategy for sustainability"

Jan 1, 2011

By J. P. McKinney

A mathematical model is presented for the electrokinetic dewatering of suspensions of phosphatic clays. The modeling approach couples a boundary-element model for solution of Laplace?s equation to a recently developed constitutive equation that relates the change in solids content with applied electric field and time. The observation that the electric field controls both the maximum solids content achievable and the time required to reach that value is shown to severely constrain the application of electrokinetic dewatering strategies to an entire clay settling area. The approach, however, may be feasible for implementation as part of a continuous plant process.

Jan 1, 2011

By J. Noll

Many underground metal/nonmetal mines are using enclosed cabs on mining equipment to reduce the exposure of miners to diesel particulate matter (DPM). However, some enclosed cab systems may not be meeting their expected efficiency in capturing DPM, which could be a result of inappropriate filter use, cab leaks, or insufficient pressurization. NIOSH investigated several types of filters for reducing DPM to determine which type had the best capture efficiency. The laboratory results indicated that a MERV 8 (Minimum Efficiency Reporting Value, as defined by the American Society of Heating, Refrigerating and Air- Conditioning Engineers) filter captured about 50 percent of the DPM, a MERV 16 filter collected 96-98 percent of the DPM, and two HEPA (high efficiency particulate air) grade filters captured over 99 percent of the DPM. NIOSH also performed a field study to measure the efficiency of two cabs at a limestone mine. The cab filtration systems of a loader and haul truck were found to be over 90 percent effective in removing DPM except under certain operating conditions when the efficiency was as low as 41 percent. Evidence seems to suggest that these conditions were when a window was open in the cab.

Jan 1, 2011

By J. Kretschmann, N. Nguyen

"The Vietnamese economic growth of more than 5% per year leads this country to an enormous demand for raw materials. In the duration of ongoing expansion, the big challenge in the coming decades will be to make this process as sustainable as possible when it comes to economic, environmental and social objectives. Risk management especially in occupational safety and health (OSH) in enterprises is one of the most important tools to achieve this aim. But until now, this has not been taken into priority by Vietnamese coal mining enterprises. Main reasons for this situation can be found in deficient legislative conditions and in non-synchronized risk management systems. In contrast, Germany has implemented an adequate legal system and the German mining industry has gained lots of experiences in risk management, especially in occupational safety and health. This paper seeks to point out specific challenges how to improve occupational safety and health in Vietnam by transferring and applying German methods and standards."

Jan 1, 2011

By Peter Faust

The foundations for the new South Viaduct Bridge in San Francisco were extremely challenging due to the requirement for very large and deep piles installed adjacent to historic structures. Drilled shafts up to 12? foot in diameter were constructed to a maximum depth of 200? feet in alluvial soils and Franciscan Bedrock using an oscillator system for the installation of the permanent steel casing. This paper provides an overview of the construction techniques, the equipment, and the challenges associated with constructing 12? foot diameter shafts on this very complex project in one of the nation?s nicest landscape setting.

Jan 1, 2011

By Thais Cristina da Costa Caldas, Carlos Mauricio Fontes Vieira, Alline Sardinha Cordeiro Morais, Sergio Neves Monteiro

"This work has as its objective to evaluate the effect of the incorporation of a glass powder waste obtained from discarded and Hg-cleaned fluorescent lamp into clayey ceramics used to fabricate bricks and roofing tiles. Formulations were prepared with incorporation of the waste in amounts up to 10 wt.% into the clayey body. Rectangular specimens were prepared by uniaxial mold-press at 20 MPa to fire at 850 and 1050°C. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural rupture strength. The microstructure of the fired ceramics was evaluated by optical microscopy. The results showed that the waste incorporation significantly improved the evaluated properties mainly at 1050°C.IntroductionFluorescent lamps use mercury as a main component for its operation. This metal is potentially toxic and can contaminate soils, animals and water bodies. The problem is aggravated if considerations are made with respect to the amount of lamps that are commercialized and discharged in emergent countries like Brazil [ 1].By using appropriate recycling processes applied to discharging fluorescent lamps it is possible to reuse most constituents of these lamps into new productive processes. A study has shown that one million common fluorescent lamps can generate 900,000 tubes of clean glass [2]. Moreover, this Hg-cleaned gloss may be recycled in different products.In fact, to recovery and recycle all materials that constitute the lamp instead of discharging them. This action protects the soil avoiding the formation of environmental passives [3]. It is also relevant to mention that the glass from fluorescent lamps is 100% recyclable while its permanence in the environment would correspond to very long time pollution, since its decomposition time is undetermined [4]."

Jan 1, 2011

By S. Orangi

A representative sample of ramming paste from a peripheral seam in an aluminium electrolysis cell was taken in order to develop a process to fabricate ramming paste samples in the laboratory. To this end, paste material was compacted in multilayers in a mould designed to be representative of peripheral seams in Alcoa's smelters. The density distribution in the representative sample was measured ranging from 1.51-1.76 g/cm3. The density range obtained by the proposed methodology in laboratory is 1.47-1.77 g/cm3. The results demonstrate that the proposed fabrication method adequately duplicates paste density from the cell for both one and two layer compaction. Finally, preliminary results related to the compressive strength and Young's modulus of laboratory samples were obtained at various temperatures and are presented in this paper.

Jan 1, 2011

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

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

Jan 1, 2011

By J. D. Steenkamp

In 2002 the commissioning of an ilmenite smelter on the North Coast of South Africa was extended by three months due to the failure and subsequent replacement of the magnesia-based refractory lining. The lining failed due to the hydration of magnesia caused by an unexpected source of water. The incident resulted in significant financial losses and a prolonged insurance claim which was settled in 2009. As magnesia-based refractories are used extensively in both ferrous and non-ferrous applications, the authors of the paper want to share the experience gained from this incident with others. The paper reviews the literature available on furnace start-up practices and explains the hydration of magnesia using available sources. The incident is studied in more detail, both technically and economically, and the costs incurred are quantified in terms of the cost of the original lining. The paper concludes with lessons learned and recommendations made for future work. The intention of the paper is to stimulate open debate regarding best practices in preheating of furnaces lined primarily with magnesia. Keywords Commissioning, hydration, start-up, magnesia.

Jan 1, 2011

By Liqun Liang

Various nondestructive testing (NDT) inspection methods are available to evaluate the structural integrity of cast-in-place shafts. The widely used methods include Cross Hole Sonic Logging Testing and Low Strain Testing. Due to its advantages such as low cost, easy operation, quickness and flexibility (no need to plan ahead and prepare inspection tubes or other devices), Low Strain Test is frequently specified in quality assurance programs of many countries or when doubts arise as to the integrity of the finished shafts/piles. The method is well suited for small to middle sized shafts. However it is an indirect NDT testing method and has certain limitations. Data interpretation requires proper training, experience and judgment and, therefore, inconsistent conclusions and reporting may be provided by different testers. To avoid or reduce such inconsistencies, it is best to follow a standardized data interpretation and record classification system. In this paper, a new classification method is presented with examples. A step-by-step data evaluation and interpretation procedure is proposed with examples of real cases to help understand the LST data. The paper also makes recommendations for measures to be taken when anomalies are detected in tested production piles.

Jan 1, 2011

By Raymond W. Henn

The 32nd annual short course ?Grouting Fundamentals and Current Practice? was held at the Colorado School of Mines, June 13-17, 2011. The field demonstration portion of the course was conducted June 16 at Baski Inc.?s yard in Denver, CO. The full-scale field demonstration presents many types of drilling and grouting equipment in operation as well as numerous grouting methods per-formed under various field conditions. As part of the field demonstration, the class was shown the proportioning, mixing, testing and injection of various cement grout mixes into sand columns under controlled and recorded conditions. These sand column demonstrations have been conducted under controlled and measured conditions each year since 1999 as part of the short course. The sand column demonstrations were conducted prior to 1999, but with less quality control and minimal record keeping of the proportioning, mixing, testing, injection pressures and the final permeation results.

Jan 1, 2011

By Ailton S. Ferreira, Rubén J. Sanchez Rodriguez, Sergio N. Monteiro, Felipe Perissé D. Lopes, Teresa E. Castillo

"Polyester composites reinforced with natural lignocellulosic fibers have, in recent times, been gaining attention in engineering areas as lighter and cheaper alternatives for traditional composites such as the ""fiberglass"". One of the strongest, the curaua fiber, is today being considered as reinforcement of composites for automobile interior parts. In fact, several research works are currently being dedicated to curaua fiber composites since physical and mechanical properties are required for practical uses. In this work, the thermal behavior of polyester composites reinforced with up to 30 % in volume of curaua fibers was investigated by differential scanning calorimetry, DSC. The results showed endothermic and exothermic events associated with water release and possible molecular chain amorphous transformation. Comparison with similar composites permitted to propose mechanism that explains this DSC thermal behavior.IntroductionThe modem composite materials, especially those reinforced with synthetic fibers such as glass and carbon, have been used since last century to attend the demands required by most technological fields, from home appliances to aerospace [1]. In fact, fiber composites offer significant advantages over monolitic materials, such as common metallic alloys, plastic and ceramics. One of the most important is the ratio between the ultimate stress and the density, known as the specific strength. For example, in common glass fiber polymer composites, the so called ""fiberglass'', the specific strength of around 400 MPa.cm3/g is higher than any conventional monolitic material. However, drawbacks exist. The energy required to fabricate ""fiberglass"" generates large emissions of C02, which are responsible for global warming. Moreover, ""fiberglass"" is not recyclable and cannot be incinerated [2]. As a result, most synthetic fiber composites end up in landfills or contribute to rivers and oceans pollution."

Jan 1, 2011

By L. A. Matthews

The embrittlement of the Ti-6Al-4V alloy by hydrogen dosing at elevated temperature has been investigated. Metal coupons were subjected to isothermal treatments in a partial hydrogen atmosphere in the temperature range from 650ºC?950ºC and the degree of embrittlement after treatment was determined by drop-weight impact testing. Embrittlement was found to be inversely related to reaction temperature as a result of the combined effects of greater hydrogen absorption and titanium hydride precipitation at the lower isothermal temperatures. Keywords Titanium, hydrogen embrittlement, impact energy

Jan 1, 2011

By J. J. Dekker

Controlling noise has proven difficult in mining, and noise-induced hearing loss (NIHL) remains common. In 2008, a South African Mine Health and Safety Council study focused on small- to medium-sized mines in relation to the milestones set by the industry to prevent NIHL. An evaluation of the compliance of ten diamond, sand, aggregate and Ready mix concrete mines and production sites with standards, legislation and best practice guidelines relating to NIHL prevention was conducted, using a noise compliance audit tool. The findings indicated that all mines surveyed had poor compliance with the international standards, compliance with International Standards Organization standards being the poorest. There was a clear distinction between the small and the medium-sized mines in their compliance with local standards and legislation (ranging from 14 per cent to 66 per cent). The areas of best compliance were audiology and medical examinations. The lower-than-expected compliance was largely attributable to shortcomings in hearing conservation programmes for occupational noise. Initiation of remedial practices in the small- to medium-scale mining sector to facilitate improvements in NIHL prevention and compliance with standards and legislation is recommended. Keywords Hearing conservation, small-to-medium mines.

Jan 1, 2011