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By V. Nenov

The study is based on the so called METASEP process which includes selective sorption of heavy metals by special bonding agents (BA), separation of boding agents from the water by means of microfiltration and/or flotation and regenerating the loaded bonding agents, leading to a metal concentrate for reuse or discharge. The bonding abilities of different bonding agents suitable for application in METASEP process were evaluated. Two groups of BA are studied, namely: chelating ion exchange resins and water soluble oligomers. The group of ion exchange resins studied includes eight organic resins, mostly chelating cation exchangers and representatives of conventional strong and weak cation exchangers. The resins with iminodiacetic and aminomethyl phosphoric acid groups showed highest affinity towards several heavy metals. The study of resin particle size showed that this parameter is a key factor influencing the kinetics of heavy metal sorption. The group of water soluble oligomers (WSO) includes polyvinyl alcohol, carboxyl-methyl-cellulose, polyvinylethylenimin and pectin. The Metal-WSO complexes were separated by Ultra Filtration. The effect of Metal-WSO mole ratio and pH was studied. Depending on the operational conditions the heavy metal retention varies within 68-99%. It was shown that regardless of pH and mole ratio Metal-WSO, separation of certain ion from the metal mixture is not possible.

Jan 1, 2006

By Barry A. Hillman

The rapid evolution of computer and field sensor technology is now providing the ability to integrate mine and office opera­tions. Digital maps and mine plans as well as CAD and GIS can be transferred to ruggcdized field computers for development of real-time mine surveys and real-time GPS machine navigation and monitoring. Surveyors can insure that their surveys arc accu­rate before returning to the office. Engineers and surveyors are also able to upload field computer-based surveys to mine plan­ning software and directly to mine equipment including shovels, drills, and dozers providing the operator of the equipment with a real-time view of their work space. Production information can be transmitted through dispatch and/or centralized mine servers to update mine plans with mining progress and production data. Static mine models then become a dynamic element of opera­tions, providing greater use of information that emphasizes the spatial aspects of the mine by providing real-time maps, produc­tivity charts, and graphs. This information can be disseminated through various mine communication systems to provide opera­tors and management with real-time feedback as well as daily and weekly reports. Integrated systems now being used in exten­sive trials arc reporting productivity increases of 4 - 7% or more thereby providing rapid payback to the mine.

Jan 1, 1998

By J. W. C. Wong, S. D. Miller, J. J. Jeffery

Pre-mining identification of acid forming mine and waste materials is of concern to the mining industry because of the potential for the generation of acid mine drainage, acid rock drainage, and soil acidity problems. Accurate identification of acid forming material is essential for developing appropriate waste management strategies to reduce environmental problems related to acid generation from sulphide containing wastes. The acid-base accounting procedure, in its various forms , is commonly used for pre-mining screening of mine and mine waste materials. The procedure is generally effective when used and applied correctly but is prone to incorrect interpretation of results which can have significant financial and environmental implications. This paper examines the acid-base accounting Procedure and the possibility of misuse of this method with special emphasis on the sampling method, the sulphide forms, the acid neutralization capacity, and the interpretation of results. Data from numerous coal, base metal, and gold mining operations are used to illustrate the application of the acid-base account. The data base indicates that overall, approximately 1/3 of all waste generated by mining and mineral processing is potentially acid forming indicating the need for correct identification and management. Problems associated with simple application of 'absolute' acid-base criteria for classifying acid forming material are highlighted and the need for developing site specific or 'relative' criteria is discussed and illustrated by case study.

Jan 1, 1991

By E. H. Cho, P. K. Dai

An acid mine drainage sludge sample, containing 3.6% Mn, 0.18% Ni, 0.15% Co and 0.39% Zn, was obtained from central West Virginia. The sample was leached at room temperature with a pH 3 sulfuric acid solution. Air was then bubbled through the leach solution at pH 4.5 to precipitate the iron. The leach solution contained 258 ppm Zn, 105 ppm Ni, 90 ppm Co and 2050 ppm Mn. Three solvent extraction studies were performed to selectively extract these metal ions in a sequential operation with DEHPA. Cyanex 272 and Lix 84. The A/O ratio was one, and the extractants were diluted ten times with kerosene. A study of solvent extraction with DEHPA showed that Zn could be extracted without Ni or Co up to a pH of 2.75. A pH of 2.75 is considered to be the optimum pH to maximize the selective separation of Zn from Mn. The separation factor of Co over manganese suggests that the two metal ions should be extracted together by Cyanex 272. The separation factor of Co over Ni indicates that these two metal ions can be separated most effectively around pH 5.3. Also, Ni can be effectively extracted by Lix 84 above pH 5.5.

Jan 1, 1995

By Jon Y. Kaneshiro, Gregory E. Korbin, Stephen J. Navin, Larry J. Stout

Sewage presently being discharged into the Tijuana River Valley pollutes the valley as well as the beaches in the South Bay of San Diego, making the beaches unusable nearly year round. The SBTO will convey flows down a 8.5 m (28 ft.) by 58 m (190 ft.) deep drop shaft, through a 3.35 m (11 ft.) by 5.8 km (3.6 mile) long tunnel, and up a 46 m by 2.7 m (150 ft. by 9 ft.) riser shaft connecting to a 1.5 km (0.95 mile) of seafloor pipeline and 1.2 km (0.76 mile) of diffusers on the ocean floor. The drop shaft will be sunk through 38 m (125 ft.) of saturated sands and gravels and 20 m (65 ft.) into the dense fine sands of the San Diego Formation. The tunnel liner has been designed as a five piece, single pass, gasketed, bolted, reinforced concrete liner designed to withstand an external head of 76 m (250 ft.) of water and internal operating head of up to 27 m (89 ft.) and to accommodate movement at the numerous fault crossings. The tunnel is contemplated to be driven with a state-of-the-art Earth Pressure Balance Machine (EPBM) or slurry shield machine through a wide range of conditions from clay to gravel with boulders.

Jan 1, 1995

By B. J. I. Adair, K. R. Weller

The bulk scavenger tailing from Aberfoyle's Hellyer Concentrator, which represents about one-third of the total tailing, runs about 2.5-3 g/t gold and 140-200 g/f silver. Both values are very finely disseminated, particularly the gold. Aberfoyle wished to establish whether ultra-fine grinding followed directly by cyanide leaching could be applied to the tailing for recovery of gold and silver. The work comprised the determination of gold and silver recoveries as a function of grind size and leaching time, the specific energy consumption required for continuous wet grinding of the tailing to the specified product size in a small horizontal continuous stirred mill, and an estimate of the rate of media consumption. The maximum extraction of gold, 23.3% was obtained from the finest product, with the highest cyanide concentration and longest leach time, confirming earlier work. A similar result was obtained for silver. The specific energy requirement for milling rose from 27.7 kWh/t for a P80 of 8.1 um to 219 kWh/t for a Pea of 2.3 um. The consumption of ceramic media was about 1.6 g/kg of final product. An extensive QEM'SEM Trace Mineral Search on the unground tailing failed to identify any gold-bearing particles but did identify silver-bearing particles which displayed a variety of textural associations and liberation characteristics.

Jan 1, 1998

By Peter Zhang, Daniel Su, Bo Kim, Berk Tulu

This paper summarizes significant findings from the ongoing NIOSH Gas Well Stability research over the past decade; in particular, the important ground control engineering considerations. Longwall-induced surface and subsurface deformations may induce gas well casing deformations and stresses, depending on a few parameters such as overburden depth, overburden geology, topographic relief, strata dip, gas well setback distance, and a gas well casing cementing alternative. Overburden depth to the mining seam is one of the most influential factors; shallow overburden depth induces large horizontal displacement and resulting casing deformation and stress, while deep overburden depth induces large longwall-induced vertical pressure. Overburden geology is another important factor affecting the longwall- induced casing deformations and stresses; the large contrast of bending stiffness at the soft-to-hard rock interfaces tends to induce large casing deformations and stresses. Large surface topographic relief and the presence of soft-to-hard rock interfaces below the stream valley bottoms may shift longwall-induced subsurface gas well casing deformations closer to the surface, thus having less impact on underground. mining operations. Strata dip magnifies longwall-induced deformations by 20% per degree of strata dip for down dip longwall excavations. The gas well setback distance is also a critical geometric parameter; the effect of longwall-induced deformation decreases exponentially as the setback distance increases. Longwall-induced casing deformation and stress will be mitigated or totally uncoupled for uncemented production casing.

Jun 25, 2024

By Peter Kowalczyk

The acquisition of submarine gravity data using airborne gravity technology is a practical reality. Ocean Floor Geophysics plans to deploy a free-swimming ROV based submarine gravimeter on a commercial basis in early 2009. The submarine instrument is a variant of the well-used GT-1A airborne gravimeter. Airborne gravity surveys are now routine. The primary factor controlling the accuracy of airborne gravimeters is the precision of the GPS measurement of vertical movement of the sensor platform. The gravity measurements along a flight line are the differences between the output of the gravimeter vertical accelerometer and the estimate of the aircraft vertical acceleration using the differential GPS system. The principle difficulty of moving an airborne gravimeter to a free-swimming submarine platform is the necessity to have an accurate real time estimate of the changing elevation and hence changing vertical acceleration of the platform; GPS doesn't work underwater and an accurate estimate of depth fluctuations to the necessary precision is difficult to acquire. It is interesting that the airborne gravity gradiometer technology, which competes with the airborne gravity technology, was first developed as a classified military application for use by missile submarines during the cold war. Gradiometers were developed for this application specifically to avoid this problem. A gradiometer does not require as accurate an estimate of its vertical position to make a useful reading- it measures gravity gradients, not the gravity field itself.

Jan 1, 2008

By L. Adler

Determining whether a railroad locomotive will skid under varying conditions is a fairly routine, pervasive problem. However, some of the equations provided are wrong, others are at best murky. All require correction or clarification. Skidding during heavy braking is a crucial safety problem, possibly resulting in loss of control and collision. It can also be an economic detriment, ruining wheels and tracks and, by inhibiting acceleration, causing reduced full-speed times. While skidding is less likely for rubber-tired equipment, a comparable problem exists for tractor-trailers operating on poor surfaces. The primary reference is to the SME Mining Engineering Handbook (pp. 14-11, Eqs. 7 and 8), which is taken as authoritative and normative (Brantner, 1973). Fundamentally, the physical weight of the locomotive can never be negative (-). However, based on this reference it can be negative on adverse grades, during braking (Eq. 7), and on favorable grades, whether accelerating or braking (Eq. 8). Additionally, it should be noted that the term rW should be Rw. To avoid having the locomotive weight turn out negative, "absolute value" brackets must enclose the right-hand expression of both equations. Also, the weight of locomotive can be greater than the right-hand side value introducing the common "greater than or equal to" symbol (>_). While these alterations are easy to make, the use of the algebraic sign associated with each term is still confusing, as

Jan 1, 1991

By A. A. Mathews

INTRODUCTION When Palmer King asked me to prepare a paper for this conference, it seemed quite appropriate, since I am Chairman of Subcommittee No. 4 of the U. S. National Committee on Tunneling Technology and we are presently making a detailed study of contracting practices. Before the end of this year, we expect to publish our report containing guidelines aimed at improving our contracting practices and minimizing the problems which develop therefrom. The American construction and mining industries today are glowing examples of the ingenuity of man pitting his wits against the unknown. Without the promise of rewards commensurate with the perils faced and the effort expended, it is doubtful that these industries could have reached their present state of advancement. Nevertheless, these industries are still primitive compared to many others such as aerospace and electronics. That our present contracting practices leave something to be desired is evidenced by the fact that many of our underground projects wind up with tremendous increases in estimated cost, financial disaster, and costly dispute and litigation. The situation is aggravated by the current economic uncertainty, energy crisis, and shortage of materials. At the same time, if our industries are to develop their maximum technologic potential, we must employ contracting practices which will encourage that development. Most of the contractual problems related to underground construction are associated with risk and its management. Unless all of the ramifications of this subject are understood, it will be difficult

Jan 1, 1974

By Hu Wenjun, Li Maonan

Mine ventilation systems mostly are ventilation networks with fixed-quantity branches. The solution to the problem of ventilation networks with fixed-quantity branches is obtained by choosing the fixed quantity branches as chords and using Hardy Cross iteration method. The solution usually is feasible but may be not economical. This paper takes minimal annual ventilation electricity cost as an object, considering the power of main fans and boosters, natural ventilation pressures and resistances of regulators, and builds up a nonlinear programming model. A set of initial values of the nonlinear programming can be obtained by using Hardy Cross method, The MAP technique then used to find a set of local optimal solution The running procedure with a simple example is dicussed. Mine ventilation systems mostly are ventilation networks with fixed quantity branches. In the networks, air quantity of branches are generaly regulated by increasing branch resistance or air pressure. A comon approch to the of the networks with fixed quantity branches is to formulate it based on Kirchhoff's current and voltage laws and the solution is obtained by Hardy Cross iterative technique. The solution usualy is feasible but may be not economical. The optimal plan of air quntities regulation of mine ventilation network should be to make the solution satisfy both required quantity of work places and minimal ventilation operating cost. It is the purpose of this paper to introduce a new approch and computational experience of nonlinear programming of the optimal problem.

Jan 1, 1991

By M. D. Chatham

Revolutionary electronic monitoring and control systems provide a gold mine of diagnostic and prognostic information. Lower cost per ton results from timely operator action, increased visibility of information to production and maintenance personnel, and better fleet management. When information is effectively integrated into fleet management systems lower costs result from higher availability, longer component life and reduced repair cost. This paper will present the objectives of the Caterpillar Vital Information Management System (VIMS) and provide actual examples of successful use.

Jan 1, 1995

By R. Conor, O&apos

Wastewater treatment systems, both industrial and municipal, produce large quantities of sludge which require disposal. Sludge disposal poses significant environmental liabilities, logistical problems, and economic burdens. Minergy Corporation has developed and implemented several new technologies for the recycling of such high volume wastes as sludge, ash, and foundry sand. These technologies perform mineral recovery from the waste material, converting them into construction material and industrial feed stocks which are inert, marketable products. With a continuously operating processing system installed at the waste source, these technologies reduce handling, eliminate downstream liabilities, and reduce disposal costs.

Jan 1, 1999

By R. D. Archibald

Currently, around 100 million tons of construction materials and aggregates are shipped annually by rail. And recently, producers are looking much more carefully at rail not only to reduce fixed costs through increased volume, but also to eliminate operating headaches, such as increasing community pressures about trucks on the road, noise and dust. Many producers are uncertain as to how to enter the rail shipping business since railroads have historically been reluctant to ship small quantities short distances. This article provides strategies to help producers examine and pursue moving their rock by rail.

Jan 1, 1995

By W. J. Miles

Industrial mineral by-products occur as a result of mining and processing a primary mineral product. By-products result from concentration and separation of accessory minerals during processing or from the primary mineral during processing, for example dusts. Many companies have found it rewarding to evaluate mineral by-products from their operations and determine potential products and applications. By-products need to be evaluated for physical and chemical properties to determine possible applications and markets. Market studies are needed to determine application specifications, price structure of the market, competitive products, and to determine marketing regions. The by-products need to be evaluated for beneficiation and processing to meet these market requirements.

Jan 1, 1985

By U. Paschedag

Today's modern longwalls have to produce high outputs with maximum availability and running time with the additional requirement of ever increasing panel width and length high-performance face conveyors require intelligent solutions for the integration of drive systems and chain tensioning devices into the overall longwall automation. The fully automated chain tensioning system allows the operation of an AFC with optimum chain tension at all times regardless of actual load on the conveyor. For the heavy-load start-up, the accurate load-sharing and an efficient overload protection of modern AFC's WESTFALIA and Dodge jointly developed the integrated WB/CST drive system.

Jan 1, 1995

By Jr. Wilkinson

Mine planners are under pressure to evaluate the impact of changing economic times and newly acquired data on the mine plan. Incorporating change, such as commodity prices, customer sales, changing cost assumptions, and newly acquired geologic data into the mine plans requires quick turn-around for model building and planning to keep the mine plan on pace with changes as they are occurring. Because of the length of time required to perform some of the geologic modeling and mine planning tasks, planning frequency may not be keeping pace with the frequency of change. This paper discusses how one company has increased the frequency rate and accuracy of mine plans to keep current with incoming data, ensuring mine plans reflect the latest information, thereby minimizing or eliminating production cost variance.

Jan 1, 2010

By J. L. Fuller

This paper contains a brief summary of design descriptions and generally accepted designations for longwall ventilation systems. Various ventilation systems for longwalls developed using single-entry and multiple-entry systems are discussed. Design considerations specific to longwall mining are included.

Jan 1, 1989

This research contributes to BioMinE (http://biomine.brgm.fr), an integrated European Union project of the Sixth Framework Programme. The general objective of BioMinE is the development and integration of innovative, environmentally friendly, biohydrometallurgical processes for the recovery of metals from primary and secondary resources within Europe. The work presented in this paper deals with the initial plan of study on the sustainable use of solid wastes derived from bio-processing of European metal bearing resources. The approach involves solidifying the waste into cementitious waste composites analogous to controlled low-strength materials (CLSM). The aim is to achieve composites of adequate mechanical, physicochemical and environmental integrity, thus providing a sustainable solution for dealing with such bulk products which are conventionally unmarketable and therefore normally discarded to landfill. Assessment has been based on largely ?model? wastes anticipated to be similar to bio-processing wastes. These include an ochreous mine water sludge and an industrial goethite residue. The work indicates that wastes containing high iron and calcium contents, typical of products from bioleaching of concentrates, could be beneficially reformed as CLSM of appropriate compressive strength. Due to the high water contents of these composites, porosity and hydraulic conductivity were correspondingly high. Flow-through leach tests showed some resistance to immobilisation of toxic elements. Work is continuing to reduce the risk of toxic elements leaching under environmental conditions. This will include laboratory-scale encapsulated systems of CLSM, designed and tested to produce a novel type of engineered fill structure.

Jan 1, 2006

By S. R. Wardwell, M. J. Robison

INTRODUCTION The first phase of the Los Angeles Metro Rail Project consists of 7.1 km of subway and stations running through downtown Los Angeles from Union Station to MacArthur Park. Contract A146, Tunnels from 5th/HILL Station to 7th/Flower Station, involves tunnel construction through the heart of downtown Los Angeles. The alignment of the tunnels passes beneath twelve buildings, ranging from a 3-story below grade parking structure to numerous 12 to 14 story buildings. The soil along the alignment is alluvium, consisting of silts and clays, clean sands and gravels located above the ground water table. Because of unstable ground conditions, which led to excessive ground losses in several instances, and because of the potential for excessive building settlements, it became necessary to design and perform a program of chemical grouting. The chemical grouting program was designed such that tunneling could proceed on a one shift per day basis, with chemical grounting being performed on the remaining two shifts. Each day 21,000 to 31,000 liters of sodium silicate grout were injected through sleeveport grout pipes installed 18 m deep through the tunnel face. Tunnel advance rates of 12 m per day, 60 m per week, under full chemical grout cover were achieved. The chemical grouting program virtually eliminated both ground loss and settlement and permitted successful excavation of the tunnels. The purpose of this paper is to describe the chemical grouting program used to control ground losses and settlement on Los Angeles Metro Rail Contract A146. The paper begins with a description of

Jan 1, 1991