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By Jaril B. Lavrencic

The unique and irregulator distribution of working places in a mine always poses the two questions: - which and how much production equipment is to be used, - what production can be expected. Since the development of analytical methods would be impractical for such cases, a lot of computer programs has emerged in recent years trying to simulate the productiom process and thus find the best answer. The usege of a simulator has its dark side well felt by the author(s) of such a program: the credibility and the confidence of the customer. Using the simulator means to respect and to incorporate all the restrictions imposed by the narow underground space, methods of production, safety regulations etc., which can turn out to become a major programming effort. If the program is not properly structured, it will be used for a single special' case only, and never again. In this paper the structure and internal mechanism of the simulator is described for which the author believes that can easily be adapted to conditions of various underground and open pit mines. MINSIM tries to reach the following rather ambitious goals: 1) Estimation of the production before opening the mine, or a part of the mine. 2) Training the personnel to make decisions. 3) Making the daily time schedules for the entire fleet of the equipment units.

Jan 1, 1989

By Thomas S. Bubanovich

This paper will discuss the installation and operation of the Mundix Monitoring System at the Freeman United Coal Mining Company's Orient No. 4 Mine. Detailed explanations of the objectives set by Management, description of the mine, description of the system, installation procedures, and material used, operating procedures, maintenance procedures, and personnel requirements as well as experiences with carbon monoxide monitoring.

Jan 1, 1987

By Parris A. Lyew-Ayee

This paper is the first preliminary report on the bauxites and terra rossas of the Caribbean. It concentrates on the islands of the Greater Antilles, and for reference purposes the Yucatan Penin- sula is included. At this point, observations made in Jamaica, Haiti, and the Dominican Republic are compared with reported information on Puerto Rico, the Bahamas, Cuba, the Cayman Islands, and the Yucatan Peninsula with regard to occurrence, as well as physical, chemical, and mineralogical composition. From this, an attempt is made at classifying the types of bauxites in the Caribbean, indicating the best reserves estimates, and the process ability of these bauxites. Some suggestions are also provided to fuel the controversy over the likely source material(s) or origin of the Caribbean bauxites.

Jan 1, 1984

By V. B. Achanti, A. W. Khair

Introduction Laboratory studies were carried out at West Virginia University to investigate the rock-fragmentation mechanism of continuous miners using an automated rotary cutting simulator. The primary factors influencing the fragmentation process were found to be bit spacing, bit geometry, depth of cut and cutting-drum rotational speed. This paper presents a discussion of the effects of these parameters in achieving optimum energy consumption and minimizing dust generation during rock fragmentation. The removal of rock ridges/walls between adjacent grooves is analyzed with three hits mounted simultaneously on the cutting head, while the bit tip angle was varied from 600 to 900. Bit spacing was varied from 25.4 to 50.8 mm (1 to 2 in.) while the cutting process was assessed for varying cutting depths. Respirable dusts generated during the course of the experiments were analyzed utilizing cascade impactors. Assessment of these parameters has led to a better understanding of the cutting mechanism of continuous miners in terms of energy consumption and dust generation. A review of the literature revealed that a considerable amount of research has been carried out on rockcutting processes. Many authors agree that the mechanical cutting efficiencies of mining machines (e.g., continuous miners, shearers and road headers) are affected by a host of parameters. Some of these parameters are machine controlled, some are operator controlled, while others are uncontrollable. Efforts were focused on understanding the influence of parameters such as bit spacing, cutting depth, attack angle, bit type, drum speed, bit geometry (i.e., tip size, shape and tip angle) and rock type on the cutting process efficiency in terms of specific energy consumption and respirable dust generation (Strehig?? et al., 1975, Hanson et al., 1979, Khair et al., 1989). Roepke et al. (1976) in an attempt to study the dust and energy generated during coal cutting using point attack bits found that the dust and the specific energy consumed both decrease as the depth of cut increases. The four fundamental stages of dust generation luring rock fragmentation are identified by Zipf and Bieniawski (1989). Coal breakage by various types of wedges was assessed by Evans and Pomeroy (1966) in an extensive experimental study on British coals. Yet the industry today requires further attention and guidance to optimize the energy consumption and dust generation during the rockbreakage process. This paper attempts to give a better understanding of the influence of some of the parameters listed above and focuses on further improvement in the rock-cutting process. The specific energy consumed for different types of bits used and the respirable dust generated are analyzed in the context of the variation of a few other parameters. Laboratory investigation The experiments were performed in the Rock Mechanics Laboratories located at West Virginia University. A rock-cutting simulator designed and fabricated by Khair (1984) was utilized for this purpose. The details of this machine are available in the literature (see Khair 1984). For this study, a series of preliminary experiments was carried out to determine the optimum cutting frame advance speed. This was intended to facilitate a maximum cut depth of 31.75 mm (1.25 in.) at an advance rate of 0.525 mm/s (0.0207 ips) for all types of bits being used and various bit spacings being considered. To look into the cutting-process efficiency of a continuous miner in the laboratory, several parameters of influence are being considered. Besides the bit-geometry parameters, machine- and operator-controlled parameters, such as spacing of bits on the cutting head, the cutting head rotational speed and the total cutting depth during an experiment, are varied. At the time this paper was written, only part of the completed experiments were ana¬lyzed, and a number of experiments were still being carried out following an orthogonal fractional factorial experimental plan to assess the effect of all of the above¬mentioned parameters on the cutting efficiency in terms of energy consumption and dust generation. Three different types of tip angles, namely, 60°, 75° and 90°, and two different tip sizes, namely, diameters of 7.94 and 24.61 mm (0.313 and 0.969 in.), were used. At

Jan 1, 1999

By Maurice Rey

The copper segregation process is designed to concentrate oxidized copper ores or mixed sulfide-oxide copper ores which are refractory to normal and cheaper mineral dressing or leaching processes. Such ores contain copper silicates or highly disseminated copper minerals in a gangue not entirely free from limestone or dolomite. Concentra¬tion by flotation is, under these circumstances, not possible and the acid-consuming constituents do not permit acid leaching. A high temperature treatment at 700-800°C, in the presence of a small amount of sodium chloride and of finely divided carbon, concentrates the copper into easily floated metal by a kind of reducing chloridizing roast. The sulfides, if present, are either oxidized in the heating stage and react like oxides or float with the metallic copper in the flotation step. The ores which have the aforementioned characteristics and which are high grade enough to pay for the treatment are scarce, so that the process has only a limited application. Theory of Copper Segregation Sodium chloride, reacting with water vapor and the acid gangue constituents, produces hydrogen chloride which reacts with the copper minerals. The copper is volatilized as cuprous chloride and immedi¬ately reduced on the coal particles by hydrogen emanating from the volatile matter of the coal and from the water-gas reaction. Hydrogen chloride is

Jan 1, 1985

By Tso-Min Shih, Ching-Hua Liu, Chung-Jen Lin, Hsi-Chiang Fang

This paper presented herein, describe the special design of an open type coal dust explosion apparatus and the laboratory works for investigating the effectiveness of the parameters on coal dust explosion and the prevention of the propagation of the coal dust explosion flame. Coal sample which were taken from the San-Ying collieries, were passed through the process of crushing ,grinding and screening to get the required particle size, ranged from 40 mesh to 200 mesh under size for testing purpose, the rock dust spreaded on the surface of coal dust and water mixed with coal dusts were employed for preventing the coal dust explosion and the propagation of the explosion flame.

Jan 1, 1991

By J. LeRoy Peterson

This paper presents some of the theoretical aspects as well as some results of actual plant operation of the Ty-Hukki Classifier. Dual classification steps within a unit vessel are achieved by controlled separation of the sand product under turbulant flow conditions, followed by further classification under strictly laminar flow conditions. Plant operation has shown some of the benefits of the superior sharpness of classification to be reduction of circulating load in grinding circuits, prevention of overgrinding, increase in mill feed rate and consequent reduction in cost per ton of ore.

Jan 1, 1966

By Don Rose

I. INTRODUCTION The Atlanta Research Chamber is an UMTA-sponsored applied research facility studying tunnel design, excavation and support systems. It is located directly below Peachtree Street in downtown Atlanta, Georgia. It is included in the CN-120 contract to build the Peachtree Center subway station, a part of the Metropolitan Atlanta Rapid Transit Authority (MARTA) multi-billion dollar "Phase A" 53-mile transit project, which is 80 percent funded by UMTA with 20 percent provided by local authorities in Atlanta and Fulton and DeKalb counties (Figure 1). The Research Chamber is located immediately south of the main Peachtree Center Station cavern, and is in part an enlargement of the pre-existing Pilot Tunnel excavated to provide bidders on the CN-120 contract a view of the rock conditions (Figure 2). The Research Chamber lies some 3 meters above, and is approximately parallel to, the twin Running Tunnels. The Research Chamber is 18 meters long and has the same 5.5 meter diameter horseshoe shape design dimensions as the twin Running Tunnels.

Jan 1, 1979

By Michael Brittan

The AARL elution process has recently been introduced to the North American mining industry by Bateman Engineers Inc. The process is described along with its noteworthy features. Design and operating considerations are discussed.

Jan 1, 1998

By G. Bezuidenhout

The newly developed Bateman Flotation Machine has proven its versatility in roughing and cleaning flotation circuits. This mechanical flotation machine has the dual performance capability of suspending solids and dispersing air at relatively low power inputs without compromising these two important fundamentals. This new development has been successfully marketed to a wide cross section of concentrator mineral processes. The mechanical design of the flotation mechanism has been optimised to reduce operational costs and to lower manufacturing costs. Production process environments were utilised for verification of the scale-up of each cell volume size rated mechanism. These thorough investigations produced performance data which could be accurately quoted. This paper is a historical account of the Bateman Flotation Machine. Technical details of the development are covered with descriptions of the operational applications.

Jan 1, 1995

By F. J. Sotillo

Mineral processing requires good classification of particles to attain an adequate separation of minerals. This is of utmost importance in the case of sulfide minerals. An ideal classification is obtained when particles are separated at a given mesh, which is fixed according to the characteristics of each sulfide ore. Under these ideal conditions, particles coarser than the mesh of separation are recovered in the underflow, whereas particles finer than the mesh of separation are recovered in the overflow. This paper presents the results of pilot plant tests that were performed on Ag-Pb-Zn and on Ag-Au Peruvian sulfide ores using a Density Separator, and the comparison of these results with those obtained using hydrocyclones, under similar operating conditions. The results show that the ratio of circulating load is reduced by 50% by using a Density Separator with respect to that obtained by using hydrocyclones. Moreover, the effect of the improvement in the separation efficiency obtained by using the Density Separator on the kinetics of flotation is also shown. Silver recovery of the Ag-Pb-Zn ore increased by 18% whereas gold grade in the concentrate of the Ag-Au ore is doubled.

Jan 1, 1998

By E. G. Loesche

Grinding mills in which the comminution takes place between rollers and the surface of a disc, table or ring are generally known as roller type mills. The Loesche Mill, also known as the Disc Roll Mill, is a special type of roller mill in which the grinding surfaces consist of two rollers assembled over a horizontal disc or table which rotates at a relatively low speed. This design is particularly applicable to industry's present day demand for large capacity grinding mills.

Jan 1, 1964

By James R. Jones

The Surface Mining Control & Reclamation Act is a complex piece of legislation signed into law on August 3, 1977. It is the culmination of more than six years of debate by the Congress over the need for a national regulation of surface mining as opposed to the prior concept of regulation by each concerned state. It departs from the more normal type of law in that it includes very specific requirements, limitations and performance standards. In its procedural aspects, it is somewhat similar to the Clean Air Act and the Water Pollution Control Act in that it places primary responsibility at the state level, provided the state meets minimum national requirements. At the time of writing this paper, in late December 1978, the Interim Regulatory Program has been in effect for seven months. The proposed regulations for the Permanent Program, the draft Environmental Impact Statement, and the draft Regulatory (Economic) Analysis ware available for eight weeks before the close of the comment period on November 27. We are now awaiting issuance of the final versions of these documents. The states in which coal is mined, for the most part, have made sere revision to their state laws and are in the process of revising their regulations, or have just completed the revision, to comply with the Initial Regulatory Procedures. They are now faced with another new major effort to analyze and plan for compliance with the Permanent Regulatory Program, which is expected to be promulgated by the Office of Surface Mining of the Department of Interior by the time this paper is presented.

Jan 1, 1979

By M. A. Bouchat

The Kipushi deposit, where the Prince Leopold Mine has been installed, belongs to Union Miniere du Haut-Katanga and is located in the Belgian Congo, 20 miles SW of Elisabethville, at the vicinity of the Northern Rodhesian Border. The deposit is of the hydrothermal metasomatic vein-type; mineralisation took place, through the limestone of the, lower Kundelungu. This is a special fea¬ture of the deposit, compared to the other copper deposits of the neighbourhood, both in the. Belgian Congo and in Rhodesia. Actually, the primary mineralisation of these other deposits; is directly related to the stratigraphic systems: schistous dolomitic in the Belgian Congo and Roan in Rhodesia. Both facies are older than the Kundelungu and separated from this formation by a tectonic cataclysm. The valuable elements occuring at Kipushi are principally copper; and zinc. The deposit also contains smaller quantities of lead, precious metals and other elements including germanium.

Jan 1, 1960

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 Stephen R. La Brooy, Tong Deng, Pritam Singh, David M. Muir, A. J. Monhemius, G. W. Warren, E. Peters

The controlled addition of ammonia to cyanide solutions inhibits the leaching of copper minerals but extracts up to 80% Au using as little as 10% of the cyanide compared with conventional cyanidation of copper-gold ores. The solubility of copper minerals and copper speciation in solution is dependent on NH3, CN-, pH and Eh. Rotating disc and electrochemical studies show that gold is leached by a mixed Cu-CN--NH3 complex with either Cu(II) or O2 as oxidant. This complex is slowly oxidised to CuCN and Cu(OH)2 by air.

Jan 1, 1993

By D. W. Fuerstenau

In mineral processing, the last century of the current millenium has been the century of froth flotation. The process did not result from fundamental research, but was developed over the years by empirical methods. In more recent years, our understanding of the fundamental principles of the flotation process have made significant strides. This paper reviews some of the historical perspectives of developments in flotation reagents, the development and application of experimental tools for delineating flotability and interfactial phenomena, advances in flotation fundamentals, and the development of flotation kinetics, both macroscopic and microscopic subprocesses. Through the application of surface chemistry, the flotation process has permitted economic utilization of a vast array of complex ores.

Jan 1, 1999

By J. J. Peshel

As per the current conceptual design presented by the Department of Energy, the exploratory shaft facility (ESF) becomes a part of the repository if the Yucca Mountain site is found suitable for repository development. Therefore, the design of the ESF should be compatible with the performance requirements for the repository. The construction methods selected should limit to the extent practical, the degree and the extent of damage to the surrounding rock mass. The ESF construction and operation should be compatible with the site data gathering activities, such as geological, thermomechanical, hydrological and geochemical testing.

Jan 1, 1991

By Rossen Halatchev

The production sequence optimization of open pit mine is a procedure that reflects the exploitation conditions over life of mine. These conditions are determined by the geological characteristics of the deposit, requirements of the mining and processing technologies and economic parameters of the exploitation. From a technological point of view the production sequence optimization deals with two aspects - spatial and time. Each of them plays a tremendously important role in searching for the optimum solution of the problem. This paper treats the time aspect of the production sequence optimization. This aspect is revealed in the context of the problem of the working zone formation of the open pit mine in time. The problem formulation places an accent on the determination of the theoretically possible time distribution of the waste and ore quantities of each bench of the open pit mine. A mathematical solution to the problem has been developed based on combinatorial analysis. The solution provides a multi-variant investigation of the production sequencing with the use of an optimization model developed as a linear programming formulation. The model objective function uses the Net Present Value as a criterion for assessing the effectiveness of production sequencing. A case study is provided for the conditions of Assarel copper open pit mine (Bulgaria) to illustrate the applicability of the approach. The results obtained reveal the complex nature of the variation of the Net Present Value as a function of the mining factor.

Jan 1, 2002

By J. D. Shenk

The White Cliffs diatomite deposit occurs in a lacustrine facies of the Quiburis Formation, an Upper Miocene to Pliocene basin-fill sediment of the lower San Pedro Valley. On-going geo-logic mapping has defined an 2.5-3.0 m (8-10 ft) thick ore zone near the mill site, several marker beds, a NNW-trending high-angle normal fault, and a NW-trending syncline. The diatomite has an average loose-weight dry bulk density of 130 kg/m3 (8 lbs/ft3) and is presently marketed outside Arizona for asphalt filler. Current development is projected to yield 3500 mt (4000 st) of finished product, with an estimated 91,000 mt (100,000 st) of finished product obtain-able from several other nearby sites.

Jan 1, 1988