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By G. Machiavelli, P. Bevilacqua, G. Ferrara, T. P. Meloy

During several years of operation in Europe, South Africa and other locations, the Tri-Flo process has demonstrated substantial improvements in dense-medium dynamic-separation systems. The reasons for this improvement are: • a high-sharpness separation due to the multistage system and the application of new concepts in the design of the regeneration circuit and in the control of the medium Theology, and • the possibility of performing two cuts at different densities using a single separation device and a single regeneration circuit. This paper discusses the above points in detail with particular reference to the multistage technology (based on the circuit analysis theory) and to the control of the medium rheology (based on recent work in the modeling and simulation of the rheological behavior of dense suspensions). Concerning the multidensity separation, information is given on the new three-stage separator where the high-density separation is performed by the first stage and the low-density separation is performed by the second and third stages. This configuration (already realized in two operating plants) was selected because no particular sharpness was required at the high-density separation, while high sharpness was required at the low-density separation. However, the configuration can be inverted or a fourth stage can be added (at very low additional cost) to provide two stages for each separating density. The importance of achieving a high sharpness separation is related to minerals (industrial minerals in particular) where the density difference of the phases to be separated is very low (as in processing of lithium ores, feldspar- and others). Information is provided on plants operating in South Africa and Canada, for the beneficiation of lithium minerals and on a plant under construction in Italy for the beneficiation of feldspar. Finally, the importance of making the separation at two densities is emphasized with particular reference to coal; i.e., producing a low-ash premium coal and recovering, in the middling, a by-product without losing heating value. Also, very important for some minerals is the production of a high-grade concentrate (at the first stage) suitable for sending directly to metallurgy (e.g., chromite ores) and the production of a low-grade concentrate that can be further treated. In this way, a higher overall recovery of the valuable mineral can be achieved, and, at the same time, a reduction of the treatment costs can be obtained. All of the above applications were once considered impossible.

Jan 1, 1995

By John Murray, Daniel Ebin, Robert Gould, Yiming Sun, Lizan Gilbert

The Atlanta Plane Train Tunnel West Extension is being constructed at Hartsfield-Jackson Atlanta International Airport using the Sequential Excavation Method (SEM). The tunnel has shallow ground cover and mixed-face conditions and passes underneath the SkyTrain and MARTA stations and airport terminal buildings. It includes a twin tube Bifurcation with a span of over 45 feet and ground cover of 12 feet. A flat roof is being constructed at the Bifurcation to maximize rock cover and minimize surface settlements. This paper focuses on design and construction challenges for the Bifurcation and tunneling beneath the world’s busiest airport, while minimizing impacts to operations.

Dec 1, 2022

By P. F. Mataich

"Why bother with computer control?" This question and others like it have been heard over and over again by those who have tried to convince operating men that there are sound merits to installing a process control computer. At IMC we have done a great deal of thinking and talking about computer control. In the course of these discussions the operating people have asked a number of questions about computer control. These questions and our answers to them make up the main part of this article. Obviously, the answer as to whether or not to go into computer control will be an individual problem conditioned by your company's circumstances. What I hope to do here is raise some questions, give you an idea of our thinking on the subject, and lay out some general guidelines for you to consider.

Jan 1, 1965

By J. P. H. Steele, T. Vincent, C. Debrunner, M. Whitehorn

For a variety of reasons, the need for automation of underground mining equipment is growing dramatically, e.g., improved safety and health, availability of labor, deeper mines, and desire for more focused excavation. While there has been tremendous progress made in this direction, much needs to be done to reach the holy grail of an autonomous mining machine. This paper reviews a number of technological developments and presents research and development needs for future development. A report on our current project for the Western Mining Resource Center at CSM is included.

Jan 1, 2000

By C. L. McKenzie

American Girl Mine is located in the Cargo Muchacho Mountains in the southeastern Imperial Valley of Southern California. Production from the current open pit mine and heap leach recovery system began in early 1989. Previous mining and gold recovery took place commencing in 1987 at the Padre Madre site, situated adjacent to the American Girl site to the southwest. In mid-1990, a 790-tonne-per-day underground gold mine and mill went into production. Approximately 6,500 troy ounces of gold per month are recovered from the combined open pit underground mine operation. Copper in the form of Azurite [Cu3(CO3)2(OH)2] and Malachite [Cu2CO3(OH)2] are abundant in the mined ores (Henshaw, 1942). The high solubility of these minerals in caustic cyanide solutions has a negative impact on carbon adsorption and electrowin processes. This paper presents the results of monitoring programs, process chemistry, and control changes introduced at American Girl Mine to abate production complications in the refinery and measures taken to minimize solution gold losses in the adsorption circuit(s).

Jan 1, 1993

By Y. Pan, V. V. S. Vytla, P. Tukkaraja, R. BHARGAVA, S. Jayaraman Sridharan

Panel caving is an underground bulk mining method that utilizes gravitational force for mining massive, steeply dipping, and deep-seated ore deposits at a lower operating cost. To control dust and gas emissions entering the production level during the extraction of ore from the draw points in a panel cave, relatively negative pressure is created in the cave by installing an exhaust fan in the exhaust drift located on top of the cave. Since caving is a dynamic process, the design of an effective ventilation system is a challenging task, and therefore, estimation of airflow resistance offered by the broken rock inside the cave is critical. The complex and dynamic nature of caving also makes it difficult to predict the airflow resistance by using traditional approaches. This study investigates the effect of changes in the bulk porosity of the broken rock on the cave airflow resistance using computational fluid dynamics (CFD) approach. The results show an inverse relationship between the cave airflow resistance and the bulk cave porosity. The pressure-quantity characteristic curves presented in this paper provide valuable information for sizing and operating an exhaust fan used for a mature panel cave ventilation.

May 17, 2022

By P. Croney

Environmental monitoring requires major effort and expense but management of data receives less attention. A modem database system can manage hydrochemistry, water levels, meteorology, geology and downhole geophysics data and is flexible to allow the storage of ad hoc data. Reports can be customized by the user and derived data generated from input values. The production of high quality maps with contours and hydrochemical diagrams is an essential part of the reporting process. These maps integrate directly with the current site survey information. These facilities are best provided by storing the data in an industry standard database such as Oracle or Access to which customized AutoCAD and Microsoft Office routines make direct SQL calls.

Jan 1, 1997

By Yi Luo, FENGLIANG WU

Mine gob has long been a safety concern in the coal industry due to the air flowing through the gob area. Therefore, knowledge of the airflow distribution and locations of hazard zones in longwall gob is important to prevent and control these hazards. Due to the inaccessibility of mine gob, many numerical studies have been performed to simulate gob air leakage using computational fluid dynamics (CFD) programs, but most of the studies isolated the gob from the mine ventilation network (MVN) with only predefined pressure boundary conditions. The MVN is, in fact, not static in a dynamic longwall mining process, and it consequently changes the boundary conditions and the gob flow field (GFF). Therefore, the MVN should be incorporated in the CFD model to prescribe the transient boundaries. However, it is very challenging to couple the 1D MVN and the 2D/3D GFF to make the mine ventilation simulation realistic. This research uses a proposed novel finite tube method (FTM) to couple the MVN and GFF. In the FTM, the GFF is discretized into a finite number of flow tubes, each of which is formed by two adjacent streamlines. These tubes connect the MVN into a new coupling network. Based on the FTM, a model for gas migration in gob is established for delineating the hazard zones of explosive methane concentration and spontaneous combustion.

By Erhard M. Winkler

The rapid decay and disfiguring of stone monuments in urban and desert rural areas has challenged conservators to protect stone surfaces from premature decay. They attempt to halt the natural process of stone decay and possibly to restore the original strength lost mostly by chemical weathering and the loss of binding cement. Ageneral solution is not possible because the physical and chemical characteristics must be considered for different stone types. The failures of stone preservation and restoration are greater in number than the cures. The need for repair of stone decay goes back to evidence of Roman replacement of decaying stone. The presence of excess water in buildings has long been recognized. Moisture tends to enter masonry from air in humid climates, a most important but often underrated factor (Fig. 1) suggesting that sealing should be the answer. Undesirable staining and efflorescence result in accelerated scaling. Today, the great variety of chemicals available to the modem conservator for sealing. consolidating, or hardening stone fall into two very different categories: surface sealers and penetrating stone consolidants, or a combination of both. SEALERS Sealers develop a tight, impervious skin which prevents access of moisture. Surface sealing has saved monuments from decay by eliminating the access of atmospheric humidity. Pressure tends to develop behind the stone surface by moisture escape. Efflorescence, crystal growth action, and freezing can cause considerable spalling (Anderegg, 1949). Flaking results when moisture is trapped behind the sealed surface. Yellowing and blotchiness are also frequently observed. The following sealants are in common use today: linseed oil, paraffin, silicone, urethane, acrylate, and animal blood on stone and adobe. Extensive cracking and yellowing has resulted soon after application. In the past many such treatments have created more problems than cures: 1. Linseed oil and paraffin have been in use for centuries. Embrittlement and yellowing occur rapidly because these are readily attacked by solar ultraviolet radiation. 2. Animal blood as paint has temporarily waterproofed adobe mud and stone masonry. The origin of blood paint has a religious background rooted in the Phoenician and Hebrew cultures. Instant water soluble dried blood can substitute for fresh blood. Winkler (1956) described the history and technique of the use of blood. 3. Silicones have proven very effective and are long lasting. In contrast, acrylates, urethane, and styrene are generally rapidly attacked by UV radiation (Clark et al., 1975). Sealing of Different Rock Types Granitic rocks have a natural porosity traced to 4.5% contraction of quartz, during cooling of the parent magma, compared with only 2% contraction of all other minerals; protection against the hygric forces may require waterproofing of granite in some in- stances. The Egyptian granite obelisk in London is an example. Soon after its relocation from Egypt to London, Cleopatra's Needle was treated, in 1879, with a mixture of Damar resin and wax dissolved in clear petroleum spirit; surface scaling became evident after half a year of exposure to the humid London atmosphere. The treatment of the ancient granite monument from Egypt has denied access of high relative humidity (RH) in London to the trapped salts inherited from the Egyptian desert and has protected the monument from decay (Burgess and Schaffer, 1952). The sister obelisk set up in Central Park, New York City, has fared less favorably because similar treatment was done too late, only after the salts hydrated and hundreds of kilograms of scalings disfigured the obelisk surface (Winkler, 1980). Surface coating of other common stones may be needed. Crystalline marble absorbs moisture from high RH atmospheres: dilation may ensue when curtain panels bow as the moisture starts to expand during daily heating-cooling cycles. A good sealer may prevent the moisture influx provided that no moisture can enter from the inside of the building. Limestones, dolomites and all carbonate rocks are subject to dissolution attack by rainwater, especially in areas where acid rain prevails (Fig. 2). The interaction of sulfates in the atmosphere with the stone can be halted by waterproofing to avoid the formation of soft and more soluble gypsum. The stone surface attack can be diminished if nearly insoluble Ca-sulfite crusts can form, instead of Ca-sulfate. Replacement of fluorite or barium compounds at the stone surface acts as a hardener, rather than a sealant. Sandstones have generally high porosity and rapid water travel can occur along unexpected routes and from any direction. Any surface sealing may do more damage by scaling and bursting than if the stone is left without treatment. Sealing of sandstones is therefore not advised at any time. Testing the efficiency of sealants: Several authors discuss waterproofing materials, silicones, urethanes, acrylates and stearates, as to their water absorption, spreading rates of water on the treated surface, water vapor transmission, resistance to efflorescence, and general appearance (Clark et al., 1975). De Castro (1983) measured the angle of contact of a microdrop (0.004 cm3) on a stone surface as characteristic of the wettability. Laboratory tests and limited field performance are described by Heiman (1981). The crest of a Gothic sandstone arch, which was sealed with silicone,

Jan 1, 1994

By Tony Szwilski

A correlation between the rank, ash content and coal seam discontinuities and coal strength/stiffness is discussed. Rebound hammers were used to evaluate the strength properties of two coal seams. The coefficient of variability of the rebound tests are compared with those of laboratory compressive strength tests by other investigators.

Jan 1, 1985

By H. Huang, R. N. Gow

"EH-pH diagrams are useful tools in understanding how mineral surfaces react in solution and particularly how aqueous conditions can be changed to enhance mineral leaching processes. Successful application of these diagrams, however, requires that several considerations be kept in mind to prevent what had been termed as “gross errors” in their calculation and use. In this paper, the aqueous Cu-S system is used as the basis for explaining the mass-balanced method of calculating EH-pH diagrams with the STABCAL thermodynamic equilibrium software. A breakdown of the Gibbs’ Phase Rule and how it is used in STABCAL to modify the diagrams is included. The methodology was applied to the aqueous Cu-As-S system, and resulting diagrams were compared against examples of those generated using the predominant-ion method. The complexity of such diagrams increases with every additional component, and competition between species becomes more apparent, as can be seen by curvature in the resulting mass-balanced diagrams. The complete diagram for enargite (Cu3AsS4) is shown. It compares well with spectroelectrochemical measurements from Raman spectroscopy and cyclic voltammetry studies.IntroductionInnovation in the field of processing arsenicbearing copper ores has been of particular interest. Copper arsenic sulfosalt minerals such as enargite (Cu3AsS4) and tennanite (Cu12As4S13) are now frequently prevalent in ore bodies as the oxide and easily leachable sulfides become harder to find. These minerals, unless pretreated somehow, concentrate in copper sulfide flotation processes, in turn concentrating the arsenic levels. Increasing environmental restrictions on arsenic content for smelters makes the hydrometallurgical processing of these concentrates more favorable. While enargite is considered one of the more refractory copper sulfides, more so than chalcopyrite (CuFeS2), there are still several methods, both industrially proven and in development, that are capable of processing these ore types. Alkaline sulfide leaching can be used as a pretreatment method to solubilize arsenic selectively (Delfini et al., 2003; Anderson and Twidwell, 2008; Tongamp, Takasaki and Shibayama, 2010a, 2010b), or the entire metal content can be leached using acid-type leaches such as acidified ferric sulfate (Dutrizac, 1981; Hackl et al., 1995; Klauber, 2008), or the chloride assisted, CESL (McDonald and Muir, 2007) or nitrogen species catalyzed (Anderson, 2003) processes can be used.As development of these leaching technologies proceed, it is also important to develop an understanding of the mineral thermodynamics. To date, there are numerous studies on the Cu-Fe-S-H2O system, particularly as it relates to chalcopyrite leaching, yet few studies have done on the Cu-As-S-H2O system. Computer-generated EH-pH diagrams have been employed to illustrate the importance of thermodynamic calculations in providing insight into such a system."

Jan 1, 2016

By Mahaboob Basha Shaik, Shakuntala Tudu, Indrajit Paul, Chandra Sekhar, Neha Gupta, Amit Kumar, Srinivas Dwarapudi, Arvind Kumar Patel

In this study, the effect of colemanite and calcined colemanite (CC) addition on the properties of iron ore pellets is studied. The pellets are prepared in a lab without and with 0.2% colemanite and varying amounts of CC from 0 to 1.0 wt%in steps of 0.2%. A reference pellet is prepared under typical plant conditions, and the properties of the reference pellet are considered as the base value for improving the cold compressive strength (CCS) while maintaining the other parameters at an acceptable limit without altering the pellet. The study also aims to provide a detailed characterization of colemanite and calcined colemanite to better understand their behaviour during firing. The lab-scale results show that the CCS of pellets made with 0.2% colemanite was reduced by 222 points (60%) as compared to the reference pellets due to crack formation during firing. The results show an improvement in the CCS of the indurated pellets with CC dosage up to 0.4%, and decreasing strength is noted thereafter. It is observed that the swelling index increases with the increase in calcined colemanite dosage. To simulate plant conditions, reference pellets and pellets with optimized CC dosage were fired in a plant furnace.

Oct 16, 2020

By John M. Moore

Within the Pofadder district of Namaqualand, South Africa, economically exploited deposits of bedded barite and zinc-lead-silver-copper sulfides occur in close proximity within highly metamorphosed mid-Proterozoic pre-tectonic para¬gneisses of the Namaqualand Metamorphic Complex (NMC) (figure i). The paragneisses belong to the Bushmanland Group (SACS, 1980) that comprises a relatively straight-forward regional sequence of basal leucogneisses, intermediate mica-sillimanite schists and glassy quartzites, and a mixed upper zone of banded iron formations (BIF), minor marbles, quartz muscovite schists and localised uppermost quartz-pebble conglomerates and amygdaloidal mafic gneisses (Joubert, 1974) (figure ii). The base metal and barite mineralisation occurs in close association with BIFs, generally above the glassy quartzites, although in some cases possibly below them. In the regional context, the Bushmanland Group paragneisses are, to the north, intercalated with and ultimately replaced by meta-volcanic sequences of talc-alkaline affinity (Reid, 1977) belonging to the Orange River Group (SACS, 1980). The metavolcanics are generally of acidic to intermediate composition and show evidence of subaerial formation from 'high altitude shield volcanism' with many acidic ashflow and welded tuff bands, mesocratic and lesser melanocratic lavas and some fanglomerates (Ritter, 1980). To the south and east, the schist/quartzite associations are initially intercalated with and eventually replaced by cordierite gneiss/metacarbonate/biotite gneiss associations of shallow marine affinity (Moore, 1980a). The Bushmanland Group paragneisses appear to represent sedimentary material in the extreme distal portions of a talc-alkaline volcanic environment adjacent to a shallow platform sea.

Jan 1, 1983

Approximately forty years ago, the military services began a realistic investigation of the problems involved with the replacement of high pressure gaseous systems with liquid oxygen systems. The program was temporarily discontinued because of numerous State-of-the-Art problems. Ten years later, interest in the liquid oxygen breathing concept was revived. Initial testing of this concept was completed in 1946. The ensuing years have seen the general acceptance of many cryogenic breathing systems for airborne applications. The inherent features of weight savings (approximately 70%) and space savings (approximately 80%) make it very desirable for high performance military aircraft. A typical aircraft system consists of a storage container with appropriate integrated control valving (the liquid oxygen converter), a heat exchanger, breathing regulator, and oxygen mask. Normally the liquid converter is located in the aircraft wheel well for easy access by ground crew personnel and the breathing regulator is mounted in the cockpit where the pilot can connect his oxygen mask. An aircraft system such as this will provide the pilot with eight hours of breathing oxygen after a 24 hour standby period. Early in 1960, the National Aeronautics and Space Administration sought a means of providing a cooling system for their personnel involved in fueling the rockets used in the space program. While fueling rockets N.A,S.A, personnel wore a completely enclosed butyl rubber suit and were susceptible to heat prostration. Using the concept of an aircraft system, Aro redesigned the container, heat

Jan 1, 1971

By M. Jaramillo

The Expanded West Pit of the 15 MTY El Cerrejon Mine will reach a maximum depth of270 m. Slope stability evaluations indicated that this depth, combined with structural complexities, would create a serious risk of footwall instability. Stabilization call for anchoring the footwall by installation of cable bolts, 9 to 33 m long, of multi-strand steel cable. For each of the 15 m high mining benches, a row of bolts is installed with variable horizontal spacing, depending on dip magnitude. Cable bolting is now standard operating practice and 11800 bolts will have been installed during the life of the mine.

Jan 1, 1995

By Norman Weiss

The design of an ore-processing plant requires a high degree of cooperation among the geological, mining and metallurgical engineers. The purposes of this section are to provide mill design information most commonly needed by the mine planners and management, and to summarize the kinds of information that must be supplied to the mill designer to enable him to provide a suitable plant. 28.1-BASIS OF DESIGN NORMAN WEISS 28.1.1-SIZE OF PROJECT The size of the project generally is expressed in tons of ore milled per day, but company policies differ widely in this respect, a few adhering to this set figure but many expecting the design capacity to be liberal. To some companies that follow the latter practice a 25,000-tpd milling plant that cannot reach 30,000 or 35,000 tpd without major additions is a disappointment. The engineers responsible for planning the operation must know what is intended. Equally important are operating schedules, particularly the number of operating days per week and shifts per day for ore delivery, crushing, grinding and processing. Hours per shift also are an important factor in design, particularly in the case of ore delivery, and the percentage lost time expected for maintenance, cleanup, inspection, preventive maintenance shutdowns, and many others, has to be taken into account. Frequently, the ore deposit will vary in hardness and grade to such a degree that the capacity of the mill will vary widely from year to year and cannot be expressed as a fixed figure. but rather as an average over a calculable period, such as 10 yr, or as a specific daily capacity over the first 2 yr, next 4 yr, etc., or some similar projection. A good example of this kind of situation is Asarco's Mission operation 15 mi southwest of Tucson, Ariz., described by Weiss and Vincent.' where the major rock types differed widely in hardness, so that a change in the proportion of these types in the mill feed could have imposed difficult design problems if a constant tonnage rate had been expected. 28.1.2-EXPECTED LIFE The life of a mining operation depends upon the size of the deposit and the rate of mining. The latter is a policy decision based on an economic analysis which, in turn, is based on many factors.' From the point of view of mill planning, the estimated life of the operation determines many criteria and affects many decisions on strength of structures and degree of protection of men and materials, the quality of the materials-handling and process machinery, the type of delivery systems for ore to the mill and concentrates to the smelter or market, and many others. Costly installations that may be excellent investments for a 20-yr project may be wasteful for a 5-yr operation. An example is the comparison of different methods of crushing or grinding. Take single- vs. multiple-stage grinding-the former may be found more economical for a 5-yr operation, and the other, more costly, method more economical for a 15 to 20-vi- life.

Jan 1, 1973

By A. Moharana

A massive slide at Bingham Canyon wiped out a side of the pit and covered the main haul road in and out of the pit. All pre-slide mine designs and schedules were no longer valid. New designs and schedules needed to be developed quickly to provide management with information regarding the immediate post-slide production potential and the time needed to ramp back up to full production. At the time of the slide, an effort was already underway to convert Bingham?s in-house Medium Term Scheduling Process to MineSight®?s Schedule Optimizer (MSSO). One of the main reasons for doing this was to reduce the time needed to produce Medium Term Schedules at Bingham, which involves a complex shovel-based scheduling approach with shovel productivities based on shovel type and the types of mining cuts to which the shovel is assigned over each planning period. The objective of the schedule was to maximize shovel usage, satisfy mill feed requirements of four SAG mills with variable milling rates, and have flexibility in setting truck constraints. This paper will describe how the new MSSO-based mine scheduling process met the challenge of producing new schedules for Bingham in a minimal amount of time.

Feb 23, 2014

By Christopher Haycocks

The growth of computer and ground control technology in recent years, combined with an urgent demand for low-cost fossil fuels and mineral resources, has set the stage for full-scale utilization of computers in mine planning. Steeply rising production costs and the need to preserve the environment are placing great demands on engineers to improve their mining efficiencies, which can best be accomplished by applying the full capabilities of the computer. Pressure to develop and perfect programs with an immediate potential for improving mine de- sign, reducing mining costs and extending the viable coal reserves of the country has already come to bear in the form of exploding energy requirements, environ- mental considerations and the visible limitations of other energy sources. The computer program discussed in this paper, RAMPLAN (Rock Mechanics Applied to Nine Planning), was constructed as part of a continuing effort at Virginia Polytechnic Institute & State University under the sponsorship of the Office of Coal Research to develop a suite of programs to benefit the mining engineer in improving mine design and evaluation techniques. This program averages out structural data values obtained from randomly placed or gridded point sources across a mining property and uses these values in structural design equations. The basic purpose of the program is to provide accurate estimates of mineable tonnages, based on a realistic assessment of structural conditions existing in the deposit, for use in subsequent evaluation programs. Program output, however, also provides sound engineering data for the mine planner to use in planning and laying out new properties. Mining dimensions produced by the program provide a good starting point for initial layouts; and as more refined procedures are developed for increasing and improving the quality and quantity of information from boreholes, this information may be used with increasing confidence. The rock mechanics principles utilized in the program are generally well-established with full details provided to the user. To produce meaningful results extensive input data, obtained from exploration borehole core data, outcrop sampling points, or mine samples, are required. To assist the engineer, details of the types of tests that should be conducted have been listed. By including all of the ground control equations in the program the otherwise long and tedious calculations can be performed easily and quickly, and the work can provide the basis for a more detailed ground control study. The program is written in Fortran IV Level G to run on an IBM 3701155 ASP and requires 156K storage.

Jan 1, 1973

By ANGELA NAIR AVELAR, Reiner Neumann, PAULO R. G. BRANDÃO

Three types of apatite were identified by means of cathodoluminescence (CL) images in flotation concentrate and tailing samples from the Catalão Mine in Brazil. They are predominantly blue apatite, followed by green apatite and, less frequently, yellow apatite. The chemical compositions of these types of apatite were determined by electron microprobe analysis and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS). Blue and green apatite responded well to the process, thus remaining in the concentrate, while yellow apatite remained in the tailings. Yellow apatite has the lowest phosphorus pentoxide (P2O5 ) content and largest anionic and cationic sites substitution, followed by green apatite, whereas blue apatite is the most homogeneous, with highest phosphorus (P) and calcium (Ca) grades and lowest substitution level.

Machine breakdowns and maintenance delays are large contributors to lost production and increased operating costs in the mining industry. The U.S. Bureau of Mines is investigating the applications of expert system technology to diagnostic and predictive maintenance tor mining equipment. This will help increase mining productivity and decrease operating costs, by reducing the frequency of equipment failures and repair times. The Bureau has begun this effort by applying expert system techniques to the diagnosis of hydraulic system problems on a continuous mining machine. This paper discusses the development of the hydraulic diagnostic expert system.

Jan 1, 1990