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By P. Richardson, B. Sceresini

The carbon-in-pulp and the carbon-in leach process for the recovery of gold and silver from cyanide leaching of ores is now widespread in the precious metals mining industry. However the presence of various base metals can have a detrimental effect on the efficiency and the economics of the process due to high cyani,:••? consumption and a reduction in leaching and adsorption rates resulting in poor recovery of the precious metals. Furthermore the presence of fast leaching and adsorbing metals such as copper can significantly reduce carbon loading capacity for the precious metais thereby necessitating a higher carbon inventory, more frequent stripping and poor bullion quality resulting in higher production costs. This paper describes the development and application of a process for the recovery of copper and and the recovery and re-use of the associated cyanide from the leach circuit at the Mt. Gibson Gold Project in the Murchison Goldfield in Western Australia. The process provides a means to counter-act the detrimental effects of the copper which occurs in the ore as various oxide and sulphide minerals including an extremely fine chalcopyrite powder. It has the added benefit of recovering the base metals in this instance copper, in a saleable form. The process is subject to a patent application by Reynolds Australia Metals, Forsayth N.L. and the author.

Jan 1, 1991

By J. Abbott

This paper gives a brief description of the Compania Ninera del Pacifico (CNP) a subsidiary of the Campania Acero del Pacifico (CAP), its participation in the Chilean Iron Ore mining and the gradual development of its activities. mainly in this paper, it is explained the CNP experience in the production of 34 million tons of self-fluxing pellets for Blast Furnace in a period of ten years in its Huasco Pellets Plant.

Jan 1, 1989

By Georgy Cherkashov

The geological setting, morphology and physical properties of massive sulfide deposits must be taken into account when designing the underwater systems being currently constructed for mining of this type of marine minerals. Based on more than 20 years experience of hydrothermal mineralization studies in the northern equatorial part of the Mid Atlantic Ridge (MAR) we have provided the following conclusions:

Jan 1, 2008

By Carl Eschman

Productivity from large walking draglines is primarily dependent on operator skills. This machine may be in operation three shifts a day, 364 days a year, and its output is directly related to coal uncovered and mine profitability. Dragline operators must have highly developed manual skills and be knowledgeable in mine planning and working strategies. When using equipment costing more than $25 million, some formal training is usually required before an operator is allowed to assume complete con¬trol; however, dragline operators rarely receive any structured training before operating these giant excavators. A form of apprenticeship is usually followed where an operator candidate progresses from a groundsman to an oiler position. As an oiler, he is permitted to operate the dragline for short periods under supervision. After apprenticeship, the operator is considered sufficiently prepared to operate the largest, most powerful machine at the mine. The apprenticeship training method has obviously provided the surface mining industry with skilled dragline operators; however, conditions are arising that require a realistic and effective training tool that can be accessed by mining companies. New mines -either planned, under construction, or recently opened in the West-do not have access to a pool of experienced operators and oilers as do Midwest mines. As coal mining activities increase in both the West and Midwest, demand for trained dragline operators could be required in a short amount of time. Also, the more productive techniques along with sound basics of strip mining are sometimes lost in the informal "OJT" training method. Modern draglines are the pacemakers of the strip mine, and are simply too expensive to be used as a training device where lost productivity and susceptibility to damage can directly affect mine output. The Dragline Training System is a logical first step in formally educating or retraining operators. The program, started by the US Bureau of Mines and continued by McDonnell Douglas Electronics Co. under contract with the US Department of Energy, was installed and evaluated at DOE's Carbondale Mining Technology Center in Carterville, IL, last year. It is now being operated by Southern Illinois University at Carbondale. System Description The Dragline Training System addresses specific environments and work practices encountered during an actual mining operation at a midwestern US surface mine. This area was chosen because of its high number of strip mines using large walking draglines. Most draglines in the region are Bucyrus-Erie 1370, 1450, and 2570 models, so the dragline trainer was patterned after the company's 1370 machine. Operating and emergency controls are sufficiently standardized for most large walking draglines, and peculiar dynamics and responses from any specific dragline can be programmed into the computer system. The computer simply prompts the user to select the manufacturer and any peculiar response or rate changes needed. A 46-m3 (60-cu yd) bucket is simulated, but for closer simulation, various bucket configurations can be provided. Dragline Trainer The dragline trainer uses the TV-model simulation technique. A scaled model of the dragline is positioned in a model mine. A television camera is positioned at the operator's theoretical eyepoint, and the view captured is projected into a large screen in full scale. The screen is positioned in front of the operator seated in a full-size cab at Bucyrus-Erie controls. By manipulating the controls, the trainee can operate the model dragline and observe its reaction in the television display. In addition to housing dragline controls and consoles, the wooden, oversized cab contains the digital computer, terminal, video recorder and monitor, power switch box, air conditioner, and has enough room for the instructor and five student observers. The 50:1 scaled dragline model contains servo-controlled functions for hoist, drag, swing, delta swing, and longitudinal and lateral position. The delta swing provides bucket lag during swing and a realistic pendulum action when the swing is terminated. The over-responsive second order servo system is designed to provide hoist, drag, and swing rates exceeding present draglines. In all cases, position servos are used for better control and sta¬bility. The normal rate operation of an actual dragline is computed for the specific machine and presented to the servo amplifiers as iterative position commands increasing or decreasing

Jan 6, 1982

By Edward S. Plotkin

The tunneling construction industry faces a new challenge in endeavoring to comply with the multitude of regulations and standards of the Occupational Safety and Health Administration and to work following accepted and experienced tunneling practices. Tunnel inspections appear to be gaining in priority. The national OSHA inspection activities reported for the year 1976 in the construction industry are as follows: 989 Inspections 45 As result of Accidents 186 As result of Complaints 605 General 153 Follow Up 34% Were found to be in compliance 714 Citations were Issued 1,825 Violations were found (201 of which were serious; 1573 were non-serious; 51 were imminent danger. There were no recorded failures to abate a violation in our industry.) The five general priorities by which a company would be scheduled for an inspection in descending order are: imminent danger situations, reports of fatal accidents or catastrophies, inspections in response to valid employee C( taints, inspections of work places covered by National Emphasis Program NEP, (OSHA's NEP has been designed to impact on any industry having a very high injury or illness rate) and finally random inspections of work places covered by OSHA. The following criteria in selecting companies for random inspections is used by OSHA.

Jan 1, 1979

By G. Righettini, P. Mousset-Jones

Diesel powered vehicles have made underground mines more efficient, but with the advent of DPM regulations, in most cases, extra ventilation and/or engine emissions control technology will be required. Using fuel cell powered vehicles will not need these measures to be taken. Nine US underground mines of varying production rates and mining methods were studied to determine possible ventilation reductions if their diesel fleets were replaced with identical fuel cell powered vehicles. Factors that might limit ventilation reductions, such as heat and the effects on other pollutants were determined for each mine. The ventilation cost savings and other benefits of fuel cell vehicles show that when they become commercially available they have the potential of being viable alternatives to diesel vehicles.

Jan 1, 2004

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 O. Guyot, T. Mulpeter

Sadiola Hill mine is located in the sub-Saharan part of Mali. In its first two years of operations, Sadiola Hill mine had already exceeded expectations with respect to profitability, plant capacity, metallurgical recovery, cash costs and social integration into the area. The advanced control system installed by the authors has been a major contributor in the substantial throughput of the mill over the design tonnage with no loss of recovery. The run-of-mine ore at Sadiola consists of soft clays with a varying percentage of grit, producing a high viscosity slurry. The percentage of grit fed to the plant varies on an hourly basis. This combination was expected to have a large impact on the milling circuit and determined that the early installation of an expert mill control system would be advantageous. Svedala Cisa OCS©, was selected as the most suitable support software. The operational rules and control philosophy are housed in the OCS© graphic-oriented fuzzy expert system while a model­based Soft Sensor has the remarkable ability to detect the variations in grit in the feed. Designed during the second half of 1996, commissioning of the system began in March 1997, the OCS was fully on-line by September. With the implementation of the optimising control strategy a throughput of 5.0 million tons relative to the target of 4.4 million tons was achieved for the 1998-operating year. The Sadiola project confirms that advanced process control techniques are among the most cost-and time-effective methods of improving metallurgical plant performance. The recipe that worked at Sadiola is a mix of metallurgical expertise, proper software selection, adequate design of control philosophy, and excellent plant support and follow­up. The early decision, design and installation of the mill control system has resulted in an enhanced Return on Investment.

Jan 1, 2000

By T. N. Moore, E. M. De Souza

Because jackleg rock drills are a potential source of hand vibration exposure, they can effectively produce Hand Arm Vibration (HAV) Syndrome in their operators. This will affect operator efficiency and mine productivity. As a result, a significant amount of work has focused on redesigning rock drill handles using new materials to minimize hand-transmitted vibration. In previous work developed by the authors (1991), a detailed study was undertaken to determine the effectiveness of using elastomer covered handles in place of the standard steel design. The results indicated that, for an elastomer-based handle design, the overall acceleration level experienced by the hand can be reduced by as much as a factor of three, relative to the steel handle. It was also shown that this reduction takes place predominantly in the frequency range above 500 Hz. This paper presents an investigation of the long-term effectiveness of an elastomer-cushioned handle under different conditions underground. In this study, sponsored by the Mining Industry Research Organization of Canada (MIROC), a number of cushioned handles were quantitatively and qualitatively tested in five operating mines. The vibration testing program has indicated that the cushioned handle can reduce overall vibration levels by as much as a factor of three. The qualitative assessment program of the cushioned handles by the drill operators has indicated some degree of preference for the cushioned handles over the steel handles, if certain design modifications are performed. This research program indicated that cushioned handles have the potential to become the dominant method with regard to vibration reduction and operator performance.

Jan 1, 1994

By R. L. Pozzo

The electrochemical nature of mineral-grinding media interaction in the wet grinding of one and two sulfide mineral ores was investigated with regard to the flotation behaviors of the minerals. Two iron sulfides (pyrite and pyrrhotite) and mild steel were used to represent the sulfide minerals and the grinding media, respectively. Galvanic currents in two-and three-electrode combinations under abrasive and non-abrasive conditions were correlated with the floatabilities of these minerals under corresponding conditions.

Jan 1, 1988

By Jack Barrett

The oxidants which participate in the bacterially catalyzed oxidation of minerals are dissolved oxygen and some aqueous iron(III) complexes. Speciation studies indicate that these complexes consist of iron (III) -sulfate and iron (III) -arsenate ions. The complexes have different oxidizing powers as indicated by their calculated standard reduction potentials. The thermodynamics of the oxidations of pyrite and arsenopyrite are related to the mechanisms of the reactions. The mechanisms are discussed in terms of primary processes occurring on the mineral surfaces and the secondary reactions of the primary products. The importance of the conclusions to plant operation is discussed.

Jan 1, 1993

By Bernie W. Martin, Paul MacLeod

The new St. Clair River International Tunnel Project presented unique challenges in planning, permitting and approval. The project straddles the border between the Province of Ontario and the State of Michigan necessitating the review of U.S. approval legislation that has not been used in 60 years. The preparation of an environmental impact report to satisfy the legislative requirements for the Federal laws of the U.S. and Canada as well as the Province of Ontario and the State of Michigan presented a daunting task. In all, over 200 external contacts were made in carrying out the environmental approvals and permitting work. The definition of the alternatives including the NULL option were documented along with the impacts and mitigation measures. A "Modified Delphi" technique, along with other methodologies, was used for alternative evaluation and selection. A formal and informal public consultation process was undertaken which involved over forty major presentations and external meetings. A unique alternative to the traditional design, tender, build contracting practice was adopted; The Negotiated Compressed Process (NCP).

Jan 1, 1993

By Bruce McKinstry

INTRODUCTION In June of 1992, the Bureau of Reclamation, United States Department of the Interior, awarded the contract for construction of the Sixth Water Aqueduct to the Fedrick-Redpath Joint Venture. This aqueduct, a segment of the Diamond Fork Power System, Central Utah Project, diverts water from Strawberry Reservoir into Sixth Water Creek and, when complete, will replace the old Strawberry Tunnel which was driven in the early 1900's. The new aqueduct is being built primarily as a result of deterioration of the old tunnel, but will also have a higher capacity and more positive control than the old tunnel as well as the capability to incorporate a turbine into the system at a later date. The Fedrick-Redpath Joint Venture is comprised of C.R. Fedrick, Inc. of Novato, California and J.S. Redpath Corporation of Tempe, Arizona. Fedrick, with its experience in pipelines and heavy construction, will construct the 4200 ft surface pipeline and flow control structure; Redpath, the managing partner, performed the underground work consisting of a 600 ft vertical shaft and 3300 ft tunnel. The project is located in the Uintah National Forest, approximately 20 miles east of Provo, Utah at a mean elevation of 7000 feet above sea level.

Jan 1, 1995

By Francis S. Kendorski

INTRODUCTION Drift design problems in caving operations are a re¬sult of the geologic factors contributing to the overall success of the system, of the engineering factors dictated by economic and technical considerations, and of ore production practices. Combining these factors, a rational underground sup¬port system of rock reinforcement, light steel channel section or welded wire fabric, and shotcrete can be de¬signed based on rock fracturing, rock load, abutment loadings, ground movement, expected repair and desired flexibility. The design concept uses the effect achieved by restraining, reinforcing, and maintaining some of the intrinsic strength of the fractured rock mass composed of interlocked blocks of intact rock and rock fractures. Three different examples of drift support design in hypo¬thetical mines using the caving system are given. Caving is a system of underground mining where ore is extracted by means of gravity after the ore body is allowed to fail by removing support from underneath. The rock mass of the ore body fractures and flows ver¬tically downward to let gravity do as much work as pos¬sible. Caving differs from many other mining systems in that blasting is used only to initiate the rock mass failure by removing the rock supporting the ore but not to break the ore itself. The initial movement of the rock mass dur¬ing failure and the consequent crushing and grinding during the continued movement serve to reduce the ore to particles of a manageable size, with only limited sec¬ondary blasting necessary. The broken ore is extracted from the bottom of the failed rock mass through funnels of some sort pre-excavated in the rock. Ore extraction must continue or the swell of the broken rock will even¬tually fill the cavity and stop further rock mass failure and movement. The excellent general discussion on block caving in the SME Mining Engineering Handbook (Julin and Tobie, 1973) adequately covers the principles and application of this type of underground mining. Many rock mechanics aspects of block caving have been covered by others (McMahon and Kendrick, 1969; Swaisgood, et al., 1972; Mahtab and Dixon, 1975; King, 1946) and will not be reviewed further. Maintaining the stability of production drifts is one of the most troublesome problems plaguing the mine manager in a caving operation. Many factors contrib¬ute to drift support problems, and identifying the causes of instability and producing a reasonable support design are two steps toward achieving stability consistent with the mine plan. This chapter sets forth a technique for the design of support systems for production drifts in caving opera¬tions. The basic support system elements employed are rock reinforcement, welded wire fabric, and shotcrete. Recognized as contributing to the design are the factors of rock load, additional load from mining activity, rock fracture characteristics, repair expected, and flexibility. It must be emphasized that the drift must first be stabilized as for a tunnel, and the additional strengthen¬ing for mining-induced loads cannot contribute to the initial premining stabilization, or the reserve of strength is used up. MINE PLANNING The efficient mine planning engineer not only must satisfy the economic, human, and environmental aspects of his task but must also consider the mechanical con¬sequences of his plan. The problems created for the mine by placing parallel drifts too close, by crossing drifts on different levels with inadequate, if any, separa¬tion, and by installing connections and crossovers in the haulage plan without regard for the effective spans cre¬ated, are only a few of the problems a mine planning engineer can create for himself and the mine. The effect on immediately adjacent mine areas when an area is caved is important to drift design because the removal of vertical support from a rock mass causes the weight of that rock mass to be shifted elsewhere. The adjacent rock mass will carry this load and reach a new equilibrium with the applied stress. The advancing front of stress increase that results from caving (and many other mining systems) is generally called the abutment load and is the increase in stress over the gravity or tec¬tonic stress that already exists, as shown in Fig. 1. In general, the abutment load will be similar in nature to the stress change found around an opening in rock and will be taken as causing an increase in the vertical prin¬cipal stress, due to an approaching caving boundary, so that

Jan 1, 1982

By Boris M. Vorobjev

The paper in question discusses a wide range of topics on the coal mining environment in general and on computerized coal mine environment systems in particular. The emphasis is being made on methodological aspects of coal mine environment with reference to computerized monitoring systems Classification of computerized coal mine environment monitoring system is suggested by the author with specific reference to coal mining operations. Coal quality control system at all levels (coal face to regional levels) is also discussed briefly hereunder, since coal quality is one of the major factor for environmental management. An integrated coal mining economic and environmental management super-system is presented in this paper Review Of the UN/DTCD, UNDP European Regional project "Computerized Coal Mining Systems" is presented here. Conceptualization of a new European Regional project on Coal Mining Environment and Economic Management is also a topic discussed in the paper.

Jan 1, 1992

By C. D. Harrison

The 1990 Clean Air Act Amendments specify national objectives for reducing sulfur dioxide emissions from coal-fired power plants System-wide reductions can be achieved by combining various emissions controls technologies and allowances, or compliance credits, that can be purchased, sold, or traded. As part of the Coal Quality Expert development project funded by U.S. Department of Energy and the Electric Power Research Institute (EPRI), Black & Veatch has developed an interactive computer tool, the Acid Rain Advisor (ARA). ARA allows the user to develop integrated system-wide compliance plans by comparing the costs and emissions reduction benefits for emissions allowances and various SO2 control technologies such as coal cleaning, fuel switching, and scrubber retrofits.

Jan 1, 1992

By J. M. Velazquez, J. H. Meza Viveros

This paper describes some of the parameters and technologies used at the Mexicana de Cobre smelter, and discusses the principal design parameters and new technologies that are being implemented in a smelter-expansion project designed to increase the production capacity of anode copper from 180 to 300 kt/year (200 to 330,000 stpy). In addition, some parallel projects under construction in the smelter plant are described.

Jan 1, 1999

By R. J. Roman

During the refining of primary magnesium metal: a spent flux (sludge) is produced which is considered a dangerous waste by the Washington State Department of Ecology. Four years of research, testing and marketing has identified two beneficial markets for the spent flux: 1) as a fertilizer and soil admendment as a result of the material's high potash and nitrogen content and its high lime equivalence and 2), as a roadway deicing agent to clear roads of ice and snow as a result of both the salt content and the flux containing chemical compounds which exothermically react with water.

Jan 1, 1988

By M. Fornaro

A small size quarrying activity (3 different quarries with an overall production in blocks less than 10.000 m3/year) has been exploiting for a long time the ?Tonalite? deposit of Adamello-Presanella. In 1967, given the outstanding natural beauty of the area, a natural park has been established with the aim of preserving environmental quality and, at the same time, of providing a sustainable development to the area. Because of the potential impacts of a mining activity in such a context, a specific study has been recently carried out in order to define if and how the quarries could co-exist with the park, beyond the ?administrative results? of a classic environmental impact assessment. The paper deals with the process that drove to the conclusion that the activities are not ?a priori? incompatible with the aims of the park. In the opinion of the authors, a responsible quarry management, which must take inspiration from the care given to environment by traditional alpine productive activities (e.g. the use of water, of wood, and of the stone itself), and take advantage of modern technologies in terms of emissions and safety, can be considered not only compatible with the protected area, but even able to positively contribute to the protection of the land and environment (Barisone et al., 2001). A series of specific prescriptions, which have been adopted by the Park Authorities after this study, are also discussed in the paper: only the definition of suitable spatial and temporal limits, the adoption of effective technical practices and a strict control are considered to be able to drive this ?exceptional? activity towards the final goal of real sustainability.

Jan 1, 2007

By A. H. Morris, W. Harrison

1. INTRODUCTION Roadheaders have a shadowy origin - probably in Eastern Europe - but were introduced to Europe and the West by the importation of a Russian PK3 machine by the National Coal Board in 1961. A number of features rendered this type of machine an attractive tool for coal mine operators: its flexibility of operation, its combined cutting and loading ability, the opportunity it provided of making any shape of roadway, as well as its ability to cut some rocks. Encouraged and sponsored by the National Coal Board, the development of roadheaders was taken up in Great Britain, notably by Anderson Strathclyde and Dosco; in Europe, predominantly in numerical terms by Voest Alpine and Paurat. Over the 24 years since the importation of the first PK3, evolutionary development has taken place to the extent that machines are now available in many forms up to 120 tons in weight. Machine design has altered, partly as a result of increased power requirements and partly in line with the use of a ripping or a co-axial head. However, the basic concept remains: a boom containing a motor and transmission gear, with a driven cutting head at its extremity and capable of universal movement urged by hydraulic rams mounted on the boom turret and on the machine deck. Generally, the turret, hydraulic powerpack and all other necessary equipment are mounted on a chassis, which contains a discharge conveyor, the whole being carried on caterpillar tracks so that a complete machine entity is provided. Figure 1 shows how the weight, power and - non-proportionally - the cutting ability of machines have increased over the years. From

Jan 1, 1985