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By D. Nilsson

This paper demonstrates the importance of including a discount rate in the determination of the optimum final' depth of an open pit. Without a proper discount rate, a pit will probably end up too deep. Another consideration is future underground mining. If underground mining is profitable, the pit may need to be shallower. Of all of the investments needed, only mining equipment and the underground mine should be included, and amortization and depreciation should not he included in the study.

Jan 1, 1997

By Ahmet Unal

Inexpensive and effective means of delivering courses to mining engineers who live at remote and scattered locations remains to be a challenging issue. Computer-based instructorless but interactive multimedia delivery is a good substitute to traditional short courses and one-way broadcasts. Such a system, enhanced with a wide area network, is an inexpensive alternative to two-way broadcasts and even to a traditional university. Course material can either be delivered on compact disks (CDs) or on-line from the host servers over the phone lines using a personal computer and a modem. Although technically not feasible using ordinary telephone service lines at the present time without further modification, advances in this field indicate that this up and coming medium may dominate the competition in the future. This paper investigates the present and the future of this technology and discusses the experiences gained in creating and disseminating a prototype multimedia CD which was created at the Rock Mechanics and Explosives Research Institute of the University of Missouri-Rolla to teach a portion of a course in Ground Control. The hardware and software used in creating the audio, 3-0 graphics, animation dips, video clips, and movies are listed. The structure of the program and the way how interactivity was achieved is explained in detail.

Jan 1, 1996

By J. A. Reizes, C. A. J. Fletcher, T. Jancar

Spirals play an important role in fine coal and mineral processing. To date, almost all spiral designs have been empirically based. Although many operational units have evolved utilising this approach, it does not necessarily lead to optimal spiral designs. This paper presents the preliminary results of a collaborative computational and experimental research program to understand the detailed separation process which will ultimately lead to a parametric assessment of alternative spiral designs through computational simulation. Unlike the empirical approach, a computational simulation is only subject to the fundamental physics of the fluid flow. No prior knowledge of the generic spiral flow is necessary. The computer code implements a robust finite volume technique to predict the three dimensional fluid motion. A height function method is used to model free surfaces and the code is capable of handling arbitrary spiral geometries. Preliminary validation of the computational simulation is carried out through analysis of an existing spiral design -the Mineral Technologies LD9 unit. Computational flow predictions are compared with experimental measurements obtained using a number of techniques, including sampling and flow visualisation, for flow test cases where no solid particulate is present.

Jan 1, 1995

By M. ]. [Mohkam

The paper describes the features of the problems encountered and the countermeasures taken for two different tunneling projects. Where, slurry shields were used to excavate, in soft heterogeneaous water-bearing grounds, tunnels passing at very low cover beneath existing foundations of H.T. electric pylons, underground structures and major utilities. In order to avoid any ground failure and/or damage to the existing structures, one option was ground treatement by grouting or freezing technics. However, it was judged that, based on previous experiences, excavation with slurry shield could be carried on securely using an appropriate slurry enriched with polymers and applying a well determined pressure at ground face. A three dimensionnal limiting equilibrium analysis model was used to determine proper confinement pressures. And, the appropriate slurry compositions were stabilished based on laboratory test results. The tunnels were excavated successfully, no ground failure was experienced, and the maximum settlement recorded (on pylons) didn't exceed 3 mm.

Jan 1, 1991

By Steven A. Tesdahl

Maintenance means keeping equipment running or restoring it to operating condition. However, the 21st century will usher in a broader need for equipment management, a cradle-to-grave strategy to preserve equipment functions, avoid the consequences of failure and ensure the productive capacity of equipment. Profitable future mining operations will have reduced the 35% of operating costs typically spent on maintenance and the unfavorable impact of downtime that often multiplied these costs by 300%. They will survive those operations that tried to carry outdated "maintenance" thinking beyond the year 2000. These surviving operations will have applied modern management techniques, technology and information to align the efforts of people with the needs of equipment. Future managers will use equipment management as an integral part of an overall production strategy. They will see it as a means of raising productivity, improving performance and minimizing downtime to maximize profitability. This global thinking will characterize all operations planning to survive in the competitive world of mining of the next century.

Jan 1, 1998

By M. Balakrishnan, K. A. Natarajan, J. M. Modak, J. S. Gururaj Naik

The ability of various fungal species isolated from gold mines to uptake gold and base metals such as zinc, copper, iron and lead from gold-process cyanide effluents was investigated. Under identical treatment conditions, different strains showed wide variations in their ability to take up gold and other base metals. Aspergillus terreus exhibited as high as a 60% gold uptake. Almost complete removal of zinc was possible with various fungi and with the yeast Saccharomyces cerevisiae. Studies at various metal concentrations showed a higher gold uptake from dilute solutions, and studies with Aspergillus niger showed that gold uptake by living cells increased gradually as the contact time increased. Metal uptake capacities between living and nonliving cells were also compared. A waste biomass (ABM- I), obtained from a fermentation industry, wasalso identified as having a high gold uptake capacity. At 5% (W/v) solids, ABM-I could efficiently remove up to 83% of the gold contained in an effluent solution within 24 hrs.

Jan 1, 1995

By Darryl Amick, Keith A. Prisbrey, Lee E. Plansky

The problem addressed was to develop automated image analysis of metal welds to replace unreliable and costly 100% visual inspection. The objective was to evaluate neural networks combined with features from gray level surfaces. Photomicrographs of the welded seam in Zircaloy-4 channels used in nuclear fuel rod assemblies were examined. The methodology used was to select a set of morphological feature coefficients from Bessel Fourier morphological feature coefficients extracted from digitized photomicrographs. The selected morphological feature coefficients were then used to train a neural network. The approach was verified initially by successfully training a neural network using the known, secondary chemistry of the alloy welds. The results were good. The Bessel Fourier coefficients captured sufficient information from the metallographic images to distinguish weld quality. This approach has the combined advantages of compressing the images through Bessel Fourier coefficients and give the ability to rapidly process large amounts of data using neural networks.

Jan 1, 1993

By P. van der Veen

There are two key reasons for this presentation: - Sustainability - Improving the economic, environmental and social impact of mining. As I will discuss in my presentation we see sustainability throughout the mine life cycle as critical for successful mine development - that is the mine makes a successful contribution to economic development and poverty alleviation for the host community and host country and at the same time the mine is a successful investment for the investor. - Knowledge Sharing ? The World Bank is not only a development bank, but also a ?knowledge bank?. One of our key functions is the dissemination of usable information and knowledge. We are here not only to share our experience but to learn from your experience as well ? two reasons that fit clearly with the mandate of the World Bank Group.

Jan 1, 2003

By V. T. Vacariu, P. D. Georgescu, N. Tomus

To assess the potential for radioactive pollution unique to the environmental conditions of the Bacau phosphogypsum waste dump, surface samples were taken, drillings were performed on the entire waste dump's height, and the Ra226 distribution on the height and surface considered to contain a medium content of the radium of 0.57 Bq/gr was studied. Thus, the waste dump's radioactive potential was estimated at 30-40 Ci in equivalent Ra226. Also analyzed was the granulometric composition of the phosphogypsum and the distribution of Ra226 on granulometric orders, which indicated that the radium was concentrated in the very fine fractions. Parameters were set up for the classification by hydrocycloning to obtain a fine class (less than 41 microns) having a radium content of more than 0.9 Bq/gr and a coarse class having less than 0.37 Bq/gr. A chemical process was devised for removal of the radium from the phosphogypsum with the possibility for recovering the contained sulfur.

Jan 1, 1999

By D. W. Niosi

In this chapter, a review is made of the various stages of an exploration program, mineral rights acquisition methods and the partners involved in an agreement, the after- tax cash flow approach using present value discounting principles, the establishment of computerized financial models for assistance during the negotiating stages for a mineral property, and the various evaluation techniques and their specific applications during different phases of an exploration program. A set of examples is shown encompassing the initial target-seeking stages to the ultimate feasibility study stage.

Jan 1, 1979

By R. Lee Wooten, Marco D. Boscardin, James M. Taylor

An earth pressure balance (EPB) tunnel boring machine (TBM) and pipe jacking were used to construct a 430-meter-long segment of sanitary sewer force main. The force main was constructed by first jacking a 2045-mm-outside-diameter, reinforced concrete cylinder pipe (RCCP) casing through alluvial sands and gravels. Later, a 1220-mm-diameter, ductile iron carrier pipe was installed within the casing pipe. The main concern affecting the construction method selection was the elimination of the need for dewatering, which could cause groundwater flow from deeper, contaminated sands up across a silt aquitard into cleaner, shallower sands. In addition, the method selected reduced the volume of soil to be handled and, consequentially, the potential amount of contaminated soil to be managed. Items discussed in the paper include provisions for handling boulders and controlling ground movements as excavation and jacking occurred approximately 300 mm beneath an active,4800 kPa, 254-mm-diameter natural gas transmission pipeline.

Jan 1, 1997

By Dan G. Wasyluk, Meryl J. Klassen, Tony J. Morris, Clive H. MacKay

The Rogers Pass Project in British Columbia has involved the construction of two railway tunnels totalling 16.6 km and a 345 m deep shaft. Systematic geological mapping was carried out at four headings during construction. The paper discusses the procedures used to record the geology, structure, rock mass characteristics and excavation performance. Coded data from the geological mapping and shift inspector reports was entered into a computer data base. The rock mass quality was evaluated for both the Geomechanics and Q classification systems. Continuous computer generated graphic logs were produced showing the excavated perimeter map, geological parameters, installed support and construction activities. The tunnel logs were updated on daily basis and used during construction by project staff for evaluating support requirements and monitoring excavation progress. The specific requirements, difficulties and advantages in mapping tunnels using a computer based system are compared to those of a conventionally mapped tunnel excavation with hand drafted tunnel logs.

Jan 1, 1987

By M. S. Enders

The McDonald gold deposit is located in the upper Blackfoot Valley in Lewis and Clark County in west-central Montana, about 65 km (40 miles) northwest of Helena and 13 km (8 miles) east of Lincoln (Fig. 1). The McDonald project area covers about 20.7 km2 (8 sq miles) of elevated terrain on the north side of the Blackfoot Valley. The Blackfoot River lies 1 km (0.6 miles) south of the McDonald deposit. East Butte and West Butte rise 300 m (985 ft) above the Blackfoot Valley to an elevation of 1,750 m (5,740 ft). They conveniently divide the area into two parts. The Seven-Up Pete Joint Venture (SPJV) is a partnership between Phelps Dodge Mining (72.25%) and CR Montana, a subsidiary of Canyon Resources (27.75%). SPJV controls about 83 km2 (32 sq miles) of mineral and surface rights in the Lincoln area. The McDonald project is on state-owned and private land. The joint venture has conducted exploration since 1989 at the Seven-Up Pete, McDonald and Keep Cool areas (Fig. 1).

Jan 1, 1995

By Wang Yingmin, Xu Zhuyun

There are 3 steps in the process of forming a mine ventilation system, (1) selecting a reasonable ventilation pattern (included pit shaft arrangement); (2) optimizing of the ventilation network and (3) computing and outputting the flow splitting results of the network with the optimal ventilating equipments selected. In the past, the first step was relied on artificial decision-making. In order to design a common ventilation system, some ventilation experts were needed to participate or do some examinations. Even so, the design made was reasonable only for those experts. If there is a mistake in the first step, then even the followed 2 steps are best done, the losses are very difficult to retrieve. So that, the first step is very important. The development of expert systems provided an efficient means and tool for all engineering fields. This paper presents an expert system of selecting mine ventilation pattern and pit shaft arrangement. After testing many times, it is shown that the system can perform the first step of designing a mine ventilation system, and can help the experts doing their study works more efficiently.

Jan 1, 1991

A joint research effort by Newmont Gold and Du Pont, working with Kurtis Mooney, of Tri-Combined Resources has developed a new ore-sample bag made of "Tyvek," a spunbonded olefin. "The goal was to find a bag with the best trade-off between efficient draining of moisture, minimal fines loss and compatibility with the conveyor drying process we were developing for our new assay lab," Charles Bucknam, analytical development coordinator for Newmont Metallurgical Services states. None of the available polypropylene, cotton or canvas bags had the needed combination of properties. "Our original tests in 1987 on the plastic bags we had been using showed an average loss of 5.4% of mud sticking to the bags when they were emptied into drying pans. Part of the sample was still in the bag as a residual." Tests on bags of "Tyvek" showed low residuals when the samples were dried in the bags before they were emptied, but about 3% of the fines were lost through the seams. Mooney recommended a new bag design, with fold-over seams.

Jan 1, 1990

By J. Hanna, R. Kalathur

Over the years, Alabama's coal industry has generated, during mining and cleaning operations, about 150 million st of fine waste coal, with this total increasing at a rate of 2 million stpy. Reclamation of the fine-size wastes (containing 20% - 60% clean coal by weight) provides, free of charge, mined and crushed feed stocks for coal recovery. Also, the removal or recovery of pyrite from the tailings should eliminate a major source of acid-water pollution. Tests were made on the impounded wastes and current plant discharges to recover the coal fraction by sizing, gravity and flotation techniques. Gravity separation of the +100-mesh material produced commercial-grade coal averaging 7.6% ash, 0.8% sulfur and 13,471 Btu/lb. However, the coal yield, at about 31 % - 56%, was relatively low. Froth flotation, using mechanical and froth column methods, gave similar coal products at much higher coal recovery rates of 87% - 93%. This coal analyzed 10% ash and 1.1% sulfur.

Jan 1, 1993

By S. Ersayin, I. Iwasaki

Laboratory- and pilot-scale tests were carried out to study the effects of a magnetically enhanced hydroseparator on a magnetic taconite sample. The test parameters included feed flow rate, percent solids and magnetic field strength. Laboratory tests showed that magnetic iron losses could be effectively prevented by applying a magnetic field strength of 0.003 T (30 gauss) to a hydroseparator. A relatively uniform magnetic field within a pilot-scale hydroseparator was obtained by installing a magnetic grid within the device. The test parameters for the pilot-scale study also included the effects of magnetizing/demagnetizing the feed and magnetizing current. Magnetic iron losses were substantially reduced, even when the hydroseparator was operated at very high upward velocities. Results also show that increasing the field strength decreased the losses, but magnetic enhancement was successful even at the lowest field strengths, and the results show that magnetic iron losses were lower when the feed was magnetized. Key words: Hydroseparator, Magnetic field, Magnetic grid, Taconite processing, Magnetizing, Demagnetizing.

Jan 1, 2003

By T. Moller

There are differences in design aspects between steel and rubber linings in grinding mills. This paper describes the basic design rules for rubber liners for different grinding applications. When converting a mill from steel to rubber liners, the design must be changed from such familiar steel liner shapes as wedge bars and plates, wave liners, ship-lap, etc. to take advantage of the characteristics of rubber. Very little of the knowledge of the wear properties of steel can be used for the design of rubber mill liners.

Jan 1, 1989

By S. D. Bearden

The world's barite reserve base is adequate for at least 100 years at the current consumption rate. China, India and the United States are expected to remain the leading producing countries, and the United States will continue to be the largest consumer. None of the known substitutes for barium sulfate are expected to impact existing applications. World production in 1995 was 4.41 Mt (4.86 million st), which is about 50% of capacity. Consumption is directly proportional to hydrocarbon well installation activity. Imports are expected to continue to supply more than half of the US requirements.

Jan 1, 1998

By Abdullah Arik

The resource classification methodologies have always been a topic of research and debate. There are both traditional and Geostatistical methods used in practice. Because of the uniqueness of each ore deposit, it seems almost impossible to have a single industry-accepted norm for resource classification. Therefore, some practitioners have adapted the methodologies to suit the deposits they are working on, but many simply use the methods they are comfortable with. Another reason for the existence of varying classification methodologies is the lack of an easy and established way to measure the confidence in the estimates. Therefore, their classification becomes a subject of debate. In this paper, a new approach is offered to classify the resources using a "Resource Classification Index." The approach using this index takes into account the local variation, the spatial data configuration around the block being estimated, as well as the traditional distance measures. A case study for a gold deposit is presented to demonstrate how this new index can be used to classify the resources. The results from this approach are compared to those from two popular classification methodologies.

Jan 1, 2002