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By Sun Guangzhong, Liang Jinhuo

Adverse geological condition is a major factor which makes construction difficulty in tunneling. But if it is predicted and tunnel support is made efficiently in time, the above difficulty can be reduced. It is necessary to develop one or several effective and economical geological methods for prediction of tunnel geology while expensive and time-consuming instruments are used. This paper reviews and proposes several geological methods for prediction of fault, seam, contact zone, and groundwater inrush. These methods have been proved to be effective and economical in tunneling practice in China.

Jan 1, 1987

By D. Babich, L. Alcorn, E. Spencer, A. Smith

Noise is one of the most pervasive health hazards in mining. A compilation of Mine Safety and Health Administration (MSHA) noise survey data for Fiscal year 1990 shows that approximately 40% of the total samples taken for longwall occupations exceeded the Permissible Exposure Limit (PEL) of 100% [Gigliotti et al. 1991]. In order to properly determine workers’ exposures on longwall coal mining systems, it is necessary to provide accurate baseline measurements for these mining systems. This research was designed to develop guidelines and test procedures for identifying all noise sources that are major contributors to the underground noise exposure of longwall coal mining system workers. Once the high noise sources are identified, promising engineering controls can be tested and evaluated to reduce the noise of the sources. The measurement system used to analyze the noise sources included stationary dosimeters in a documented repeatable pattern and a time-motion study of the cutting cycle and operator’s work cycle. Significant results from the underground measurements show that the highest sound levels recorded are at the stageloader discharge segment and tailpiece controls and remained at about the same level throughout the test.

Jan 1, 2007

By Fergusson E.

An account is given of the history and operation of the Straits Tin market and the Penang price. The procedure by which the official ruling tin price is determined is presented and the way in which bids are treated is outlined: the price declared in Penang is the result of a joint operation by the two Malaysian smelters and is arrived at by finding the highest price at which the whole of the day's offerings for sale can be sold, thus reflecting the marriage of the offerings of the individual mine producers with the demand for Straits Tin from the consuming countries of the world. A system of accurate weighing, sampling and assaying of concentrates delivered to the smelters' premises enables the various ore-buying agencies of the two smelters to notify their central offices promptly of the estimated tin content of the concentrates their customers wish to price that day, so that by 11.00 a.m. both smelters will have exchanged with each other figures giving the total quantity of metal they have for inclusion in the day's market, at the same time exchanging particulars of the bids they have received. Miners are encouraged to sell regularly for cash and an evenness is thus achieved which avoids large daily fluctuations in overall quantity.

Dec 30, 1971

By Neil E. Ryan

Because of their chemical reactivity and affinity for oxygen, rare-earth elements are difficult to extract, and due to their close chemical similarity, it is an exacting task to separate one from the other. Nevertheless, these same characteristics can be used to benefit other metals by enhancing their resistance to high-temperture oxidation/corrosion and by inhibiting their corrosion in aqueous environments. This paper gives an overview of the use of rare-earths: [a] as alloy additions, [b] in coatings, and [c] when added to hostile environments, to retard rates of high- temperature oxidation and inhibit aqueous corrosion.

Jan 1, 1992

By B. D. Paphane

Since the commissioning of the Tati Hydrometallurgical Demonstration Plant (HDP), which produces Ni and Cu cathodes as well as Co salt from sulphide concentrate employing Activox® technology for leaching, no kinetic data has been generated from the plant under normal operating conditions, from start-up to steady state. Therefore, this study seeks to determine the rate of reactions in the leaching circuit with a view to obtaining kinetic data for the system under the current operating conditions. Within the five-compartment autoclave operating at temperatures of 105°C to 110°C and 1100 kPa pressure, the extraction of Ni, Cu, and Co ions into solution is achieved through the oxidation of the sulphide concentrate using approximately 50 kg H2SO4 per ton, 10 kg NaCl per ton, and 1.21 kg O2 per kilogram of S2-. The autoclave reactions showed complex kinetics, with the reactions proceeding via some intermediate(s) before the formation of products. The results suggest that the reactions were dependent on the size of the metal ion of interest and the concentrations of the metal ions in the Tati concentrate as well as in chloride leaching. The order of the leaching rate constants was Fe2+ > Cu2+ > Ni2+ > Co2+ in all the compartments studied. The rates of leaching were also found to decrease as the concentrate moves from compartment 1 to compartment 4. For compartments 1 to 3, leaching was observed to be preceded by dilution of the repulp liquor (copper raffinate). The leaching rate for compartment 5 was slightly lower than that of compartment 1 but higher than the rates of compartments 2, 3, and 4 for all the metals studied. Keywords kinetics, hydrometallurgical plant, Activox

Jun 1, 2013

By Albert Ketler

[Early Bureau of Mines research had produced a fluorescent mine illumination system which was approved by MESA under Schedule 29A for use as portable equipment Intense industry preference for machine-mounted hardware required a MESA 2G approved system. The modifications required to upgrade the portable system arc herein described.]

Jan 1, 1976

By D. F. Malan, M. Grave, J. A. L. Napier

Previous fundamental research projects have indicated the value of continuous closure measurements in deep tabular excavations for improved support design, hazard assessment and for quantifying the effect of seismicity on stope closure. This paper describes further measurements in a VCR stope to validate some of the earlier findings. Calculation of the closure ratio showed that it is a good measure to identify different ground conditions and possible hazards. This work was supported by numerical modelling results, which showed that the closure ratio is very useful in discriminating the response of different geotechnical environments. Des projets précédents de recherche fondamentale ont démontré la valeur de mesures continues de fermeture dans le cas de profondes excavations tabulaires pour une conception améliorée du soutien, de l’évaluation du danger et pour quantifier l’effet de la séismicité sur l'affaissement du toit d’un chantier d’abattage. Le présent document décrit d’autres mesures dans un chantier d’abattage VCR afin de valider certaines des conclusions précédemment formulées. Le calcul du degré d'affaissement montre qu’il y va de soi d’identifier différentes conditions de sol ainsi que les dangers possibles. Les présents travaux ont été confirmés par des résultats de modélisation numérique, lesquels ont démontré que le taux d'affaissement est très utile quant à discerner la réponse dans des environnements géotechniques différents. Vorherige Forschungsprojekte haben den Wert von kontinuierlichen Setzungsmessungen im tiefen Sudafrikanischen Strebabbau angedeutet, vor allem fur Ausbaudesign und Risikobewertung, als auch fur die quantitative Bestimmungen der seismizitatsabhangigen Setzung. Dieses Referat beschreibt weitere Messungen in einer VCR Grube um fruhere Bestimmungen zu bewerten. Dass errechnete Konvergenzverhaltniss erweiste sich als eine gute Massnahme zur bestimmung von geotechnischen Zonen und moglichen Risiken. Numerische Analyse unterstutzte die vorliegende Arbeit und deutete darauf, dass das Konvergenzverhaltniss sehr brauchbar ist um Verhaltensunterschiede der geotechnischen Zonen zu erproben

Jan 1, 2003

The value creation with kaolin clays depends on removing the colored impurities which manifests in to higher brightnessone of the most sought after properties on applications such as paper coating, paint and others. The processes for removing impurities include magnetic separation, froth flotation and selective flocculation. While the flotation and selective flocculation processes exploit the physico-chemical differences between the surface properties, the magnetic separation uses the bulk magnetic susceptibility differences between the diamagnetic clay and ferro- and para-magnetic nature of the impurities. The major advantage with magnetic separation remains high yield and no or low reagent usage. However, the magnetic separation technology suffers from low separation efficacy when finer colored impurities (<1 µm) are encountered in the feed. Use of stronger magnetic intensities during magnetic separation showed limited success; nonetheless the adverse effect due to finer size range remains a dominant effect even at 5 Tesla magnetic field. Furthermore, the presence of diamagnetic colored impurities irrespective of their sizes can not be removed. Cytec Industries has recently developed a ?bolt-on? chemical enhancement technology for magnetic separation that essentially embraces the best product performance attributes of flotation and selective flocculation while keeping the chemical usage to a minimum level and using the readily available magnetic separation equipment. The paper will outline the technology and illustrate optimization work at pilot plant magnet on a wide variety of crude accommodating the process needs and plant limitations. The major advantages of chemical enhancement technology to magnetic separation include: 1) simple extension to existing magnetic separation technology, 2) ability to produce comparable product in quality with cost effectiveness compared to flotation and selective flocculation, 3) removal of impurity minerals over wide size range, 4) removing non-magnetic impurities, 5) providing robust process with high process yield and 6) operation-friendly nature. Furthermore, chemical enhancement technology for magnetic separation has also emerged as a platform for re-moving impurities at low levels in other mineral systems as well.

Jan 1, 2014

By S. H. Ash, E. M. Brooks

"Many of the hoisting slopes at the mines in the State of Washington are driven on extra steep dips. To facilitate hoisting they are driven wide enough to provide two tracks. The cars are handled by high-speed, first-motion electric hoists and the trips run in balance.The State mining laws a provide that special man-cars be provided on slopes of 20° or more and that no one be allowed to ride while any loaded car is being hoisted in any slope in a mine. Obviously, in addition to the fact that it is more or less hazardous to ride while an empty trip is being hoisted, considerable hoisting time is lost during the day if some one has to ride the trips in the slope.Owing to the locations of pumps and various types of equipment, more or less travel is required up and down the slope. Not only to provide a proper safety factor but also to comply with the law, some other means of transportation in an¬other passageway is desirable. This is sometimes recognized in large mines by pro viding separate hoisting shafts, or slopes, and necessary equipment, which are use for transporting men and material. The handling of material in itself would justify the system in most large mines.The following description of an automatic electric man-hoist was prepared from data furnished through the courtesy of Mr. Thomas Murphy, superintendent of the Northwestern Improvement Company's mines in the Roslyn-Cle Elum coal field.The special features of this hoist are that no hoistman is required and its operation is always under the control of the person or persons riding the trip.The hoist was installed at mine No. 5, Roslyn, Washington, to provide a means of entering and leaving the mine on idle days or at night when no hoistman was on duty and to make it unnecessary to use the main hoist for a man trip during working hours. It has been in operation for about two years and has given very satisfactory service.The hoist, with all accessories, is housed in a concrete building 200 feet back from and in direct line with one of the main airways. One car with a capacity of six men operates over a distance of 1,200 feet on a 38° pitch.The wiring details of the electric circuits which control the operation of the hoist are shown in Figure 1-a.The hoist is driven through a worm gear by a 500-volt shunt-wound direct-current motor at a car speed of 120 feet per' minute. A gravity friction brake with magnetic release is mounted on the- motor shaft and is wired in multiple with the motor field coils. The hoist drum is also equipped with emergency friction brakes, which operate by gravity and are released, in case of overspeed, by the governor geared direct to the drum shaft. When these brakes set the control circuit is opened at contact 2E-2C and the motor stops.If the descending car meets some obstruction and is stopped, the hoist continues to run and unwind the rope. To guard against this occurrence, a weighted sheave wheel rides the rope 4 feet from the drum, and if the rope becomes slack the rider drops downward and opens the contact 2C-2E which stops the hoist.Limit switches, S1 and S2, are located on the hoist indicator, which is connected to the drum shaft through sprockets and chain. The pointer P indicates the position of the hoist at all times."

Jul 1, 1930

To provide an engineering solution to wood crib design and deployment strategies that will ensure safety for underground coal mine workers. This is accomplished by preserving necessary ground control requirements while minimizing support costs or by developing new support strategies to enhance ground support in difficult conditions. A secondary objective is to be able to quantify wood crib support performance to define support requirements for alternative support systems. These objectives have been achieved through a simple-to-use computer program called the wood crib performance model (wcpm).

Jan 1, 1997

By Dell H. Adams

COAL EXPLORATION Coal exploration may be defined as the acquisition of data necessary to define and acquire a block of coal which can be mined at a profit. Unlike ore minerals, coal resources are widespread and relatively abundant with supply exceeding demand in almost every case. Thus simple discovery of coal is generally not enough. The chemical and physical variability of individual coal seams, the capital intensive nature of coal mine development, and the changing patterns of utilization require that a multiphase, three-dimensional evaluation be made of each potential reserve. Factors which must be investigated include not only the quantity and quality of the coal but also the geologic, hydrologic, and engineering characteristics of the seam and its surrounding strata. Acquisition of property to provide a secure base for exploration and mine development is equal in importance to the geologic and engineering programs. The successful development of a coal reserve requires that control of coal and, in the case of a strip mine, the surface be in the form of contiguous blocks of sufficient size to support mining. PHASES OF EXPLORATION The high capital risks of coal exploration and land acquisition dictate that a multiphase program be utilized to minimize initial risk. In such a program, phased development of the data insures that each increase in capital expenditures will be justified by a corresponding increase in the level of confidence in the ultimate success of the project. Each phase is designed to provide sufficient data and property control to facilitate the decision whether to proceed to the next phase of development or to discontinue the program (Table 1). The first phase of a typical exploration program consists of a pre-

Jan 1, 1981

By A Weber, L MacNamara, H Schreiber

Design and development of the world?s largest flotation cell was completed in 2002. This was the first 257 m3 flotation cell installed in the mineral industry and represents a major development in the design of larger flotation cells. This cell has a 50% increase in volume over the widely installed 160 m3 WEMCO® Smartcell? flotation machine. In the next few years it is anticipated that 257 m3 flotation cells will be incorporated into rougher-scavenger flotation circuits in many more world class copper sulphide concentrators. The prototype 257 m3 cell, No.250 Smartcell? flotation machine was installed at Minera Los Pelambres in the front of Row 1 in the existing rougher flotation circuit. This cell is followed by nine No. 130 Smartcell? flotation cells. After the successful development phase, this unit has been incorporated as part of a row of No. 250 Smartcell? flotation machines at Minera Los Pelambres. A key to the successful development of the equipment has been the emphasis placed on fundamental hydrodynamic scale-up criteria. Hydrodynamic factors include superficial gas velocity, water (pulp) circulation through the draft tube, and pulp mixing (distribution) characteristics. This paper will review the scale-up criteria of the No. 250 flotation cell, and present a case study of the in-plant equipment testing. The case study will document the metallurgical and hydrodynamic performance of the machine. It will also illustrate the economic benefits derived by incorporating larger flotation cells in a modern copper sulphide concentrator.

Jan 1, 2007

Mother Nature controls, technical professionals model and miners decide. Decisions to explore, mine and mill. Mine decisions, mine design, planning and scheduling are subject to the quality of models û geological models, geotechnical models, resource models, density models. The closer these models are to reality, the more accurate the predicted outcome. So why is it we delegate the modelling tasks to the most junior and least experienced people? If we insist on this, we need to support them û to provide them with æexperience acceleratorsÆ. Technical mentoring is the most effective way to provide the right information at the right time. When this information (read skills) is supplied at the right time we can inject experience into the quality of our modelling and into our decision- making processes. The objective of this paper is to share those behaviours and manners that foster relationships and create frameworks for skills and experience transfer. Central to this is an understanding of how adults learn, an understanding of the basic rules of mentoring etiquette, and the three keys to building meaningful mentoring relationships. An understanding of adult learning processes and styles provides a structure within which a mentor can understand the learnerÆs perspective. Understanding the world from the learnerÆs point is critical to selecting the right language to engage, teach and transfer skills. Basic rules of mentoring etiquette like timeliness, respect and trust need to be brought into the consciousness so they can be agreed on and monitored to prevent conflicts in cultural and generational norms between the mentor and the learner.Meaningful relationships hinge on the three behaviours: truly listening, rather than just hearing; understanding the technical issues within the WIIFM (whatÆs in it for me?) question; and facilitative behaviour. Stronger and more meaningful technical mentoring relationships within our industry will bridge the generational gap and ensure we can capture and capitalise on the wealth of grey hair experience and develop an informed group of young decision-makers.

Jan 1, 2006

By E. R. Olson

The introduction gives not only a historical background but also touches on shaft sinking and surface construction and gives some general information on the Potash Conservation Regulations which the Saskatchewan government introduced in 1969. It also gives information on the corporate and local organization of Alwinsal Potash.

Jan 1, 1972

By David M. Lake

Conversion to trolley assist is a means of minimizing diesel fuel consumption, which in many mining situations offers a rapid payback of capital investment plus the inherent flexibility and maneuverability of truck shovel operation. When diesel electric truck shovel mining operation with trolley assist is compared to alternative mining methods such as conveyor systems, the trolley assist system can be easily justified in terms of return on investment, payback and increased productivity. A review of present technology, performance requirements and past experience in the mining industry has led to the development of a trolley assist system for diesel electric haulage trucks which, is proven in the mining environment, offers significant reduction in fuel consumption and increased productivity.

Jan 1, 1981

By Kevin O?Callaghan

Applying Legal Concepts - The Crown must consult, and where necessary accommodate, when: - Crown has knowledge, real or constructive, of the potential existence of Aboriginal rights or title and contemplates conduct that might adversely affect it - Duty to consult is triggered at a low threshold - How much consultation necessary? - Proportional to the strength of claim and potential impact - Spectrum: notice to direct involvement in decision making - Not duty to agree or to get consent (no veto) - Reciprocal: Duty requires good faith and sincere engagement on both sides Role of Proponents: Crown may delegate procedural aspects of its legal duty

May 1, 2010

By P M. Hetherington, F A. Pym, M P. Murphy, K E. Crook

Consultants in the mining industry have the opportunity to visit interesting deposits all over the world. Each deposit has its own set of challenges to face when it comes to defining and understanding the deposit geology and the economics to make it viable for extraction. Some of the challenges can include appropriate data capture, sampling techniques, structural characteristics, geochemistry, geophysics, lithology definition, and economic boundaries. It is essential that the practices used at each deposit (eg drilling, sampling, geological modelling, resource estimation etc) are documented and the results obtained are robust and defensible. The Competent Person is not always aware of instances where their resource estimation practices have not been substantiated. ‘You don’t know what you don’t know’ is a phrase frequently used during a mineral resource audit. Technical work to substantiate drilling, sampling, density, assaying, geological modelling and estimation processes is not always completed. Audited Competent Persons often comment: • ‘I was unaware that this was required.’ • ‘I have not had training in this area and do not know how to complete the checks required.’ • ‘This is how we’ve always done it.’ Examples of audits where it was found that geological practices were not substantiated are examined here. A discussion is included on why substantiation of these practices is important, and potential reasons as to why there are instances of unsubstantiated processes and practices are discussed.

Mar 22, 2022

By M Nehring, E Topal

Nowadays mining projects are seeking new versions of evaluation that are based on the flexibility in the project. Real option valuation (ROV) is one of the modern evaluation methods that provides a tool to adapt and revise mining projects under uncertainty and future variable movements. Most evaluation approaches simply assume that some variables are fixed, such as production rate, variable cost, fixed cost and lifetime of project. The first section of this paper reviews a comprehensive study of ROV in mining projects. The paper then introduces a new model that solves problems where previous methods lacked. The new method endeavours to find maximum mining project value by adding total cost as a function of production rate into ROV. The second section has been applied to a new model on the Century zinc mine in north-west Queensland, thus illustrating the future overview of that mine. The new version of ROV gave a significant positive value for the Century Mine, when the closure and reopening options where available throughout the life of the mine. Consequently, the new method evaluates real options to add value to mining projects, maximising projectÆs value, estimating cost function, optimising production rates and offers opportunities in projects to amplify gains or to mitigate losses.

Jan 1, 2009

By Minna Päällysaho

For the first time, the idea of sustainable development was recognised at a high political level at the UN Conference on Environment and Development held in Rio de Janeiro in 1992 (UNEP, 1992). Then the governments of the world committed themselves to promote sustainable development in their national activities and international co-operation. In 2001, the European Council approved the EU Strategy for Sustainable Development (European commission, 2011). This complements and supports the EU?s so-called Lisbon Strategy (European council, 2000) on competitiveness. The revised Strategy for Sustainable Development was approved in June 2006. Recently sustainability has had an important role in policy and decision-making while the public awareness towards limits of the environment has been rising. However, the indicators of industrial sustainability satisfy primarily the needs of corporate management and global investors. The information is often broad and non-specific and might occasionally even give a false impression. Moreover, contradictions between environmental, economical and social aspects also point out the unreliability of existing sustainability indexes. Therefore, the current state of affairs serves the interests of neither the industry nor the policy makers. Current corporate sustainability indexes and indicator systems need to be assessed with scientific methods encompassing the identification of their strengths and weaknesses. This requires quantitative and qualitative assessment and synthesis of existing indexes and indicator systems, providing new data on the functionality of existing corporate sustainability indicators. Therefore, the assessment lays the foundation for the development of new, more balanced sustainability index. Our first aim in this multidisciplinary article is to analyse existing global sustainability indexes for process industry. Second, we will introduce a first version of a new sustainability index for process industry, which includes the environmental, social and economic impacts of the plant, as well as legislation aspects.

Sep 1, 2012

By Derek J. Penrice

The Caltrain Downtown Extension (DTX) project will extend commuter and future statewide high-speed rail service into the Transbay Transit Center, which will be located in the business district in downtown San Francisco. The DTX project includes 1.5 miles of underground construction, comprising complex sections of mined and cut-and-cover tunnel. As part of the DTX preliminary engineering process, development of appropriate contracting practices, including contract packaging, procurement methods and contract terms for the underground construction, has been initiated. This paper provides a summary of the evaluations undertaken, preliminary conclusions reached, and proposed next steps to promote industry interest and maximize bid competition.