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By J. F. Peterman, M. C. Roberts

The success of any industrial mineral project requires an accurate forecast of the demand fir the material as well as accurate projections of costs and prices. This paper develops a general method of predicting mineral requirements and applies it to the case of graphite. The basic method is to explain graphite consumption in each of its major uses by the output and manufacturing technology of the using industry. Once these underlying factors are determined, they can he projected to establish future requirements. This forecast is critical to the evaluation of a new source of supply, such as the graphite resources of Upper Michigan.

Jan 1, 1990

By Nai-piu Tong, Huaren Dou, Sui-shun Poon, Leslie H. Swann

This paper mainly presents geotechnical aspects of a vehicular underpass that was built across under one of the busiest highway in Hong Kong. The underpass, in a section comprising an upper arch and invert slab, is approximately 6.2 m high at crown and 15 m wide at the base level with 40 m in length. The construction inevitably requires the underpass to be built using tunneling techniques to keep the overheadroad traffic uninterrupted. The paper will describe the design of temporary support for the tunnel excavation that was provided by an arch formed with horizontal pipes, which were installed using the pipe ramming method. The pipes arch was then supported by steel ribs founded on rock or mass concrete. Permanent lining design consideration was also discussed. Results of numerical modeling of the soil-structure interaction using the 2-D computer code FLAC will be presented. The predictions have been compared to the monitored results during construction, which indicates the prediction is in reasonable agreement with the measurement in the light of ground movement. The construction challenges will also be discussed in the paper.

Jan 1, 2003

By S. K. Kawatra, T. C. Rao, J. P. Barnwal, Durga D. Patil

Coal macerals differ widely in their surface properties and in their hydrophobicities. Therefore, it is necessary to study the flotation time dependence of coal macerals using varying concentrations of various frothers and collectors. In the present study, froth flotation is used to explore the possibility of segregating coal macerals based on their relative rates of flotation. Petrographic analysis of the various macerals in the concentrate were carried out, and the results are expressed in terms of the recoveries of various maceral groups and mineral matter. Results show that it is possible to recover a good volume of the reactive macerals without mach loss of calorific value.

Jan 1, 2000

By X. Zhou

A novel flotation device, cyclonic static micro-bubble column flotation (FCSMC), was introduced in this paper. FCSMC has been widely applied for fine coal preparation in China, and its application has been further expanded to the mineral processing industry. The FCSMC system features a unique cyclonic structure which enhances the separation performance of the column. In this paper, the cyclonic separation mechanism of FCSMC process was investigated, and corresponding kinetics equations were established to probe the separation principle of this device. Some typical examples of using FCSMC to separate different materials including coal, copper, fluorite, etc., were presented. Key words: cyclonic static micro-bubble flotation column, cyclonic separation

Jan 1, 2008

By Zhuang Jianming, Liu Qinxia, Yuan Mingliang, Mei Xiangong, Chen Jin

Up to now, the leaching of manganese carbonate ore is usually performed at high temperature of 363K and the leaching rate is lower than 90%. Although in laboratory test, the leaching rate is only 90%. This paper introduced an improved method for leaching of manganese carbonate ore. Certain ammonium salt was added to the pulp to raise the solubility of Mn2+ and reduce the adsorption quantity of Mn2+ on the ore surface. Experimental results show that a leaching rate over 95% can be obtained at the temperature >273K. The activation energy is calculated to be 7.15 KJ/mol and is lower than that of normal leaching technique. The effects of the parameters, such as particle size, pulp density and initial acid concentration on the process results are investigated. A leaching rate higher than 95% can be obtained under the following conditions: particle size below 0.25mm, leaching time 60 min, stirring speed higher than 960 r.pm. H2SO4:MnCO3>1 .2, pulp density 105-205 g.L-l. A kinetic model was deduced, verifying with actual experiments. It showed that the model can describe the leaching process successfully.

Jan 1, 1995

By Jan M. Mutmansky

While production scheduling for both surface and underground mining operations is similar in nature, a rather large array of techniques is applied in solving such planning problems. The techniques consist of both rigid operations research (OR) methods and practical procedures which are not mathematically based. In the following sections, a short summary of some of the techniques that are applicable to production scheduling problems in mineral operations is presented. The techniques discussed are: linear programming, integer programming, dynamic programming, graph and network theory, simulation, and heuristic methods. For an in-depth comprehension of these techniques, the reader is referred to any of the available textbooks on these subjects. One or more references will be listed for each topic to provide a starting point.

Jan 1, 1979

By J. M. Richardson, A. L. Mular

Metallurgical balances are fundamental to the successful design and operation of concentration and dewatering circuits. With computerized balance techniques gaining prominence in recent years, it is essential that engineers understand the basic principles that underlie the new methods, as well as the various applications for design of new plants and analysis of existing operations. This chapter discusses two important types of metallurgical balance: (1) steady-state design (2) operating data adjustment Application of computerized steady- state design balancing is demonstrated through the example of a typical copper concentrator flowsheet. Operating data adjustment to achieve a consistent balance is demonstrated for a typical concentrator operation.

Jan 1, 1986

By J. Girard-Dwyer, J. Johnson, J. Whyatt

The choice of fragmentation method is one of the most fundamental aspects of mine design, and often has a major impact on the safety and economic viability of an operation. Almost exclusively, underground mining operations rely on either mechanical excavation or drill and blast techniques to extract rock. Each of these fragmentation methods has distinct advantages and disadvantages, and each is appropriate, and economic, for different mining conditions. However, the choice of fragmentation method can have a pronounced effect on the amount of damage created in the rock mass surrounding the opening. This paper reviews a number of case studies where both mechanical excavation and traditional drill and blast were used in underground mines. Ground support requirements in the mechanically excavated areas are compared to the support requirements in the blasted sections in order to demonstrate the potential safety and cost benefits of the various fragmentation methods.

Jan 1, 2003

By James J. Brady

The basic story at Bear Swamp was how to excavate an underground chamber 79 feet wide by 227 feet long and 150 feet high, along with the related access, tarbrace, leads, power tunnels and shafts, do it under cost and ahead of schedule and still have just about everybody love you. The isometric sketch of the overall project follows. I won't go into any of the details of the physical scope at this point. Instead, we'll bring out the sizes, grades, particular problems of the different areas as we cover them. First of all, let's establish that Bear Swamp was a Target Estimate - Fee with Incentives type of contract. Gates and Fox's contract was with the project's general contractor, J. A. Jones. We were one of three contractors who submitted proposals and estimates to Jones. After much negotiation and many submittals, Gates and Fox was notified we had been selected to do the underground excavation on April 12, 1971. We had our first people back on site in two days, set up a temporary office, made our first steel order for jumbo erection, pacing our jumbo construction to meet the date when J. A. Jones would have the access portal ready for us. The shops, yards, dry house, compressor building were all erected as sites were designated for our use. At last, on Thursday, June 3, we trimmed the face and moved our 9-machine Euclid jumbo up a hastily constructed haul road and started our portal preparation of the access tunnel.

Jan 1, 1974

By Gerhard Sauer, Heimo Gold

The main advantage of the New Austrian Tunneling Method over conventional drill and blast techniques, TBMs and shields is its outstanding flexibility. Many different support concepts help to cope with all but the most adverse conditions. A considerable variety of unique additional support measurements provide a functional tool when dealing with particularly difficult conditions or restricting requirements. The resulting adaptability of NATM with respect to geometric and geologic changes is a cornerstone to providing an economic design and to a safe and unhindered execution of the tunnel work. To take best advantage of this flexibility and to emphasize its cost-saving capacity, NATM explicitly extends the design period into the construction phase. In accordance with corresponding ground classes or other anticipated conditions, a number of basic support categories and an array of additional support measurements are established during the actual design phase. The decision for applying a particular support category at a specific location and for necessary additions to the given support scheme, however, is regularly made on site after each advance, and is determined by the key persons involved in the construction. Contract documents must reflect this approach to facilitate the execution of the work and to curtail construction costs. Biased distributions of risks, however, can adversely effect the envisioned benefits. Consequently, the respective responsibilities of engineer, contractor, and client need to be redefined.

Jan 1, 1989

By Hidehiko Nakazaki, Sakuro Murayama, Mitsuo Miura, Masaaki Endo, Yoshiaki Hurukawa

This is a detailed report of construction experience of a tunnel built by a shield of rectangular cross section with reinforced concrete segments. In case of tunneling by a rectangular shield, there were the following problems to be overcom by technical developments; (1) structural joints between segments, (2) complexity in erector handling, (3) exact steering operation of shield and perfect filling of tail void left around the lining erected. Such rectangular shape of cross section has various advantages comparing the conventional circular shape as follows; (1) effective utilization of excavated space, (2) greater overburden depth, (3) stability of lining against unbalanced earth pressure caused by neighbouring construction.

Jan 1, 1979

By P. M. Fozzard

The Chaucha porphyry copper/molybdenum deposit was discovered by a United Nations team of geologists working with a ?counter- part" team of staff of the Ecuadorian government's General Directorate of Geology and Mines (DDGM) in July 1968. The exploration program formed the latter part of phase I work plan of a two-phased exploration project financed by the United Nations Development Programme and initiated in late 1964. The author was a team geologist during the period 1965-1967 and subsequently project manager for the period 1968-1972. The Chaucha property lies some 10 km (6 miles) east of the north- south-running western boundary of what was known as Operation Area No. 5. This area of some 10 500 km2(4050 sq miles) is a square truncated to the southeast and centered on the city of Cuenca, the major provincial capital (Azuay Province) of southern Ecuador. The eastern half of the exploration area is dominated by the Cretaceous- Tertiary sedimentary valley (basin) of Cuenca (Caar-Azuay) and its related drainage area. The western half, in which Chaucha lies, is dominated by the high Cordillera Occidental volcanic plateau and the western erosional valleys of the Andes draining to the Pacific. The valley that dominates the eastern part of the area [I500 m (4920 ft) above sea level] is transected by the Pan-American Highway. Because of increased agricultural activity associated with the Cuenca Valley, the area is reasonably well covered by a road network of varying quality. The high western area up to 4000 m (13,120 ft) in altitude is largely barren and completely inaccessible by vehicle. The geological reconnaissance map of the region is shown in Fig. 1.

Jan 1, 1991

By R. A. Lowe, P. B. Malla

Smectite is a common impurity in the kaolins of Georgia.This impurity is harmful to the low-shear rheology of kaolin slurries in concentrations as low as a few weight percent. The deleterious effect of smectite on the low-shear rheology is due to the swelling of the mineral. Montmorillonite containing clays were treated to precipitate a compact brucite layer {Mg(OH)2} in the interlayer region of the expandable layer silicate mineral. This treatment forms ahydroxy-Mg-montmorillonite with characteristics similar to chlorite. This treatment effectively reduces the swelling capacity of the mineral and improves the rheological properties of kaolin slurries contaminated with smectite impurities.

Jan 1, 1999

By M. Kyzeridi

The paper presents a study on the reclamation of two mined-out bauxite open pits in the area of Kefali, Itea, Greece. The mining area has been reclaimed partially in the past, but its proximity to the town of Itea and a national road with tourist traffic, rose the interest to examine various scenarios for improving the landscape and the aesthetics of the site and introducing alternative land-use for recreational activities. Geospatial data were modelled using a Geographical Information System (GIS) that made it possible to study alternative proposals in terms of final landscape profiles, volumes required to be moved and the associated costs.

Jan 1, 2002

By M. R. Paterson, M. K. Suddaby

Operational and economic factors tend to favor the application of continuous processes in preference to batch processes in the majority of mineral processing applications. In this paper, the requirement for a continuous elution process is established and the development of a large-scale pilot plant is described. It is based on a continuous elution apparatus that has a number of special features. These are the subject of various patent applications. The apparatus is suitable for adaptation to the AARL, Zadra, and other methods of elution. The performance of the atmospheric continuous elution system (ACE) is concluded to have significant advantages over the batch process.

Jan 1, 1988

By Taira Emoto, Hikozou Imaoka, Sohta Takatsu, Takeshi Suzuki, Yoshihito Minami

An Oval Section TBM (tunnel boring machine) enables excavation of tunnel with elliptical cross section by inclining the cutterhead. It is developed to utilize the proven conventional TBM technology with minimum modifications. Various types of tunnels which are preferred to have non-circular cross section can be economically excavated, reducing both overbreak and the amount of muck produced. On the other hand, an inclined cutterhead may create a number of new problems, such as in excavation efficiency and steering that are unknown in excavation works using a circular TBM. This paper reports on verification tests carried out to examine the extent of such problems using experimental models of the machine in an attempt to confirm the feasibility of the Oval Section TBM.

Jan 1, 1997

By Patricia T. Foley

An analysis of the demand for copper shows a widely varying pattern of end use. For example, copper tube is the most popular material for hot water supply in the US and northern Europe, but galvanized steel is used in Japan and plastics are used in developing countries. In addition to such peculiarities of end use, the demand for copper varies among countries depending on the stage of industrialization and the extent that the copper processing industries are developed. Brazil, with its abundant supplies of bauxite and hydroelectric power, uses aluminun in place of copper wherever possible. South Korea, with its export oriented economy and its advanced custom smelting and fabricating industries, favors copper. Understanding the details of demand in different countries enhances statistical derived forecasts and illustrates potential new markets.

Jan 1, 1986

By Kerstin Malmqvist

Simulation technique has been used for a feasibility study of a deep exploration project for massive, sulphides in an old mining district, the Skellefte field. An interactive computerized mathematical model of an ore field and a drilling procedure has been constructed. It is possible to represent varying geological structures. The model also takes in consideration economical factors such as drilling costs and ore values. On this model Monte Carlo simulations and probability calculations are done in order to estimate the outcome of different drilling strategies under varying geological assumptions. Under the specific conditions of the well known Skellefte field, it is found to be possible to even calibrate the mathematical model.

Jan 1, 1979

By R. J. Sweigard, R. V. Ramani

Estimated costs and revenues can be used in evaluating postmining land use alternatives. However, postmining land use decisions have to be made in an environment complicated by several additional factors. These factors, including cultural, natural, and managerial issues, are not as easily quantified as costs and revenues but may be more important determinants. There fore, some approach is needed to attach relative weight to the various factors. The concept of fuzzy sets assembled into a structured hierarchy facilitates analysis of the relative value of individual factors and their impact on each alternative under consideration. In this paper, a method is presented that employs fuzzy set analysis to evaluate postmining land use plans on the basis of these nonquantitative factors.

Jan 1, 1988

By Robert A. Hains, William P. Balaz, K. Payne

Ceramics are usually used to line chutes, pipes, dust collectors, separators, cyclones or bins where abrasive or corrosive material is moving. Improvements in ceramic manufacturing methods and quality, use of other abrasion resistant materials in combination with Alumina ceramic, improved adhesives and installation methods allow the use of Alumina ceramic tile in applications with impact. This paper discusses the criteria to determine if ceramics can provide a cost effective alternative to other liners for abrasive material handling applications, design parameters for liner systems, system costs, and case histories. The goal will be to provide a practical guide for improving the performance of existing ceramic lined systems or determining if ceramics is a cost effective solution for your abrasive material handling applications.

Jan 1, 1996