Search Documents

By G. Bloomsburg, R. E. Williams, S. D. Vincent

A modeling scheme is developed to simulate the hydrogeologic effects of mine design and development in unsaturated rock. Simulations are conducted using the UNSAT2 finite element computer program and hydrogeologic data from the site of a proposed mined-out waste repository at Yucca Mountain, NV. Results of the simulations are analyzed for: •variations in the direction of ground water flow and in the distribution of pressure head caused by the design of the mined out openings; and •mine design variables that affect the predicted rates of mine water inflow. Evaluating the hydrogeologic impacts of mine design and mine development in unsaturated rock is significant in several respects. Characterization of the preemplacement of wastes along the fastest path ground water flow system at the Yucca Mountain site has been a primary research effort. Ultimately, however, the degree to which waste isolation is achieved will depend largely on the post-mining hydrogeologic environment as altered by the mine design and on the radionuclide inventory and resulting heat effects of the repository. Therefore, an ongoing characterization of the proposed mined-out nuclear waste repository at Yucca Mountain, NV, is recommended. Modeling results indicate that: •mined out openings will affect the movement of ground water, both in rate and direction; •hydraulic effects of mine development depend on the hydrogeologic environment and on mine design geometry; •mine water inflow is possible in the unsaturated zone, even for mines developed in hydrogeologically homogeneous rocks; and •mine water inflow can occur at values of down ward flux that are appreciably less than the saturated hydraulic conductivity of the overlying rocks.

Jan 1, 1991

By C. J. Hunter

Prior to the commissioning of the Sansu Sulphide Treatment Plant (STP), Ashanti Goldfields' treatment facilities were capable of producing some 700 000 ounces of gold per annum. Ore sources were underground refractory sulphides, surface oxides and old tailings dams. In order to increase the mines production to 1 million ounces per annum and to accommodate the change in ore sources as surface mining moved into fresh sulphides, a part of the strategy adopted was -the construction of a new sulphide treatment plant with a capacity to mill 2.2 million tonnes per annum and produce 400 000 ounces of gold. The STP has been designed, built and commissioned. and has been in operation since February 1994. The Plant boasts the world's largest Bio-oxidation facility which is capable of treating 790 tonnes of sulphide concentrate per day at a grade of 11.4% sulphur and is currently undergoing an expansion to increase its capacity to 1050 tonnes per day. The following sections describe the reasons for selecting the BioX® Process, the plant design, the commissioning experience and the plant performance to date.

Jan 1, 1996

By Michael J. Cruickshank

MICHAEL J. CRUICKSHANK SENIOR AUTHOR Marine mining is a very broad field. It encompasses every facet of terrestrial mining but with the unique addition of a superimposed liquid overburden, which is itself mineralized. It is the unique aspects of marine mining that are discussed in this section. In keeping with the times, a systems approach is taken in the presentation of the material. The environment is first described, and this is followed in logical sequence by the common requirements for working there, then the mineral exploration phase, the exploitation and, finally, the operational restraints imposed by man and nature. Free use is made of tables and figures from original and published works and extensive listings of reference material round out each section. The title "Marine Mining" was chosen in preference to ocean or underwater mining because it is broad enough to include oceans, beaches and inland seas. The selection of terms sometimes may seem odd but they have not been chosen arbitrarily. All things are reduced, where possible, to basics and defined. Applying systems terminology, the word "platforms" is used in the functional sense and includes not only airborne, waterborne and fixed platforms, but man himself in his capacity as a working diver. If there is confusion it is often because of familiarity with a word in a context personal to the reader. For example, what does extraction mean to you-or mining or exploitation? Cost data have been interspersed throughout the section whenever they could be obtained. The use of these data should be tempered with understanding because no two situations are alike and improvements in marine technology are constantly being made. The names of individual authors are listed with each subsection. Where no name is given, the responsibility has been that of the senior author. Acknowledgment is sincerely made to the U.S. Bureau of Mines, and latterly the National Oceanic and Atmospheric Administration, for encouraging and supporting the preparation of the work ; to the secretarial staff at the Marine Minerals Technology Center and to Donald Eisman for editing. To the many other contributors who may not be listed by name, grateful acknowledgment is also due. It is hoped that the chapter will be useful to the practicing mining engineer who suddenly is assigned to marine work or to the experienced marine engineer who is equally suddenly assigned to mining work. It is not possible to put "everything-you -need-to¬-know" into one section, but. the very full bibliographies at the end of the text should adequately fill in for those who wish to know more. 20.1-THE MARINE ENVIRONMENT Marine mining is set apart as a separate discipline by the marine environment. The following subsections describe the environment from the point of view of the physicist, the chemist and the geologist. The interrelationship of these disciplines with the economic mineral potential of the oceans and seas is apparent from the description of the marine mineral resources. The marine environment is an extremely complex natural phenomenon with which the marine mining engineer must learn to live. It can be the source of his wealth or his frustrations and sometimes both. It can never be ignored.

Jan 1, 1973

By D. G. Krige

In the world mining scene, precious metals (particularly gold) have recently monopolized the attention in exploration as well as new production activities. As the major world producer of gold, South Africa plays and will continue to play a very significant role in this commodity. This role will, of course, have its consequential effects on the world's gold supply and, hence, also on the international price of gold. It is essential, therefore, and in the interests of all gold producers that the likely future pattern of gold production in South Africa be estimated such that some measure of production uncertainties can be predicted. For this purpose, some elementary geostatistical models will be used, and the main factors affecting the situation will be analyzed in broad outline only under the following headings: South Africa's basic gold ore potential in the three categories of: (1) ore remaining in existing mines; (2) extensions to existing mines via unexplored areas and/or reef horizons of lower grade; and (3) new mines, potentially deep or ultradeep. Cutoff grades - operating, marginal, and flotation, for the foregoing three ore categories, respectively. The availability of production, financial, and other resources required. Cutoff grades will, of course, depend on cost levels (operating and capital), future inflation and cost escalation trends in South Africa (SA), and/or gold price trends (in US$ and via the exchange rate in SA Rand terms). The differentials in inflation and escalation trends with those in overseas countries, mainly the USA, will, in general, set the scene for future exchange rate levels of the Rand. To predict the effect of various cutoff grades on future gold production from South Africa, it is essential to use geostatistical models. The applicability of such models is tested against past records of price, cost, and grade trends and then applied to the estimated ore potentials. These models were referred to briefly in a paper at a recent seminar on gold (Krige, 1986) but are discussed in detail herein. This lecture was intended originally to cover only technical aspects, but, in view of South Africa's position internationally and the possible effect of sanctions, internal unrest, and strikes on gold production, a brief reference to the third factor above (availability of production, financial, and other resources) seems appropriate.

Jan 1, 1988

By W. W. Hartley

Following a Major underground coal mine incident there followed a review of the role of mines rescue ? the Queensland Mines Rescue Brigade. It wasn?t until 2002 that the real change started to happen. The issue of geographical distance was addressed by mines rescue sub stations being located on the mines sites with parent rescue stations in a central location. The funding was by means of a levy on the mining industry with legislative standards and performance included. The previous Rescue Brigades were not well organised (central districts) and the application of recognised quality management practices within local management was lacking. The structure was based on other nations models and miners managing miners was an issue for the organisation. The reform was some what painful and the QMRS organisation will still evolve with continuous improvement. Queensland has the National Champion mines rescue team for the eighth year. QMRS is participating at the level in the industry of influencing emergency systems and training senior mine management in ?Emergency Mine Management? coaching the industry in emergency response systems. We have come a long way. We have had some success and there is always the challenge of setting the standards, those we should aspire to and the courage to influence the industry to higher goals of a safer future.

Jan 1, 2010

By George M. Potter

Precious gold and silver markets support substantial activity in the search for and development of improved and unconventional ore and tailing processing methods. The need for such methods 1s strengthened by consideration of increasingly low grade and refractory ores and old tailing reserves. As background for this review of new and unconventional precious metal processing, recent USBM data (1981) show annual world gold production of about 40.8 million troy ounces. In the U.S. about half the 2.8 million ounce consumption was used for jewelry and the arts, 39 percent for industry, and 8 percent for dental purposes. World silver production in 1981 was about 365 million ounces. Domestic usage the same year was about 117 million ounces. More than $ was used for photography and 30 percent for electrical and electronics. By process, about 1 percent of U.S. production of gold came from amalgamation, 66 percent from cyanidation, 31 percent from smelting ores and concentrates, and 2 percent from placers. As for silver, about 11 percent is from cyanidation and 89 percent from smelting ores and concentrates. Evidently the search for innovative and unconventional precious metal processes must include gravity concentration, froth flotation, hydrometallurgical, and electrometallurgical methods. Although smelting processes are equally important, they largely comprise nonferrous metal technology, and are not discussed here.

Jan 1, 1984

By John D. Gardner

This paper describes a process which finds the maximum worth of a mineral deposit. The procedure requires two phases. The first uses a microcomputer evaluation model to find the optimum design input, with minimum attention giving to actual mining constraints that might exist. The second phase runs the first-phase design parameters through a direct simulation model on a mainframe computer. In phase one, financial, economic, and geotechnical data are entered; and an idealized list of design parameters is output. The list includes optimum values for cutoff grade, mine life, mine size, paytons, paygrade, and payvalue. In addition, the model generates pro forma operating and cash flow statements and it indicates the maximum net present value (NPV) possible for the deposit along with the probability of that oc¬curring. The initial results imply perfect mining conditions. In phase two, when actual mining selectivity, sequence, and other practical design considerations are related in a direct simulation model to the optimum criteria found above, the maximum NPV invariably decreases. However, if it is still satisfactory (NPV greater than or equal to zero) then the maximum worth/ optimum design have probably been found in the first iteration. If, on the other hand, NPV is now unsatisfactory, then design compromises must be made and simulated, and the results rerun through the evaluation model. If several iterations fail to yield a positive NPV then the deposit is most likely unfeasible t for the forecast economic conditions used in phase one.

Jan 1, 1986

By L. Alan Weakly

This paper was presented at the ‘17th U. S. Symposium on Rock Mechanics’ on August 29, 1976, at Snowbird, Utah, at the SME-AIME Fall Meeting on September 1, 1976, at Denver, Colorado, and at the Polish-American conference on Ground Control in Room-and-Pillar Mining on August 7, 1980 at Southern Illinois University, Carbondale, Illinois. Introduction The purpose of this paper is to present a viable method of reinforcing rock pillars by utilizing fully grouted reinforcing steel and a cement- fly ash mortar. Although the fully bonded bolt concept is not new as exemplified by the present widespread use of resin bolts within United States mines and by the use of cement grouted reinforcing used as back pins in the Kiruna Iron Ore Mine in northern Sweden, (1)(2)the method of stabilizing mine pillars with fully bonded reinforcing is new. This method, called the "grout-rebar system", was first incorporated at St. Joe Minerals Corporation's Fletcher Mine in December of 1972. The system was used on an emergency basis before extensive research on the mechanics of the system could be completed. Since Decmeber of 1972, however, approximately 206 pillars have been reinforced at Fletcher and the system is currently being used on a regular basis at two other St. Joe mines and at two competitor mines in the area. Basically, this paper is a case study of the efforts, research and results of utilizing the grout-rebar system, on a selective basis, at the Fletcher Mine. In addition to information about the system, this paper will explain in detail the three rock mechanics instruments developed by St. Joe and used to measure and monitor rock movement to validate the group-rebar system.

Jan 1, 1982

ShouSteel Mining Ltd., a subsidiary of ShouSteel (Group) Co., was founded in 1959 and is located in QianAn City in Hebei Province, China. ShouSteel?s pelletizing plant uses iron ore as a raw material combined with limestone, dolostone, or olivine, with bentonite as a binder. After mixing the raw materials and forming them into small, spherical balls, ShouSteel then fires pellets in kilns for hardening. The company sells the finished pellets as raw materials for blast furnaces used to produce industrial metals such as iron. ShouSteel?s handling capacity is approximately 24.5 Mt/a (27 million stpy) of ore. The company?s production capacity is 3.2 Mt/a (3.5 million stpy) of oxide pellets and 560 Mt (650 million st) of sinters. Until recently, ShouSteel Mining had not replaced its electronic scales in its series of ingredient chambers. Because of the wear and tear on these older scales, the weighing system began to encounter regular problems. The company experienced a high failure rate from the integrator, an unstable signal, weak anti-interference ability and low accuracy. ShouSteel also found that spare parts required during repairs were consistently high in cost and that system calibration was becoming increasingly frequent.

Jan 1, 2012

By John A. Rajala

The water chemistry of the froth flotation pulp is one of many parameters which can affect the flotation process. The fluid may contain certain inorganic salts which, along with increased ionic strength, can produce undesirable flotation depression or activation. A source of a salt could be the use of calcium chloride to prevent freezing in ore cars, chutes, and bins (Anon., 1980). Alternately, the salt or salts could be initially contained in the water as in the case of sea water and some brackish waters. These salts may become more concentrated because of the need for recycling of plant water due to environmental regulations and/or economic considerations (Davis, F.T., et. al., 1976). The presence of inorganic salts in flotation pulps and their effects upon the recoveries and surface chemistries of different oxide minerals have been the object of various studies. Some researchers (Fuerstenau, D. W. and Raghavan, 1976; Fuerstenau, D. W. and Modi, H. J. 1960; Kulkarni, R. D. and Somasundaran, P., 1977) have reported that addition of a salt can increase or decrease flotation recovery depending upon the particular system.

Jan 1, 1982

By M. Misra

The processing strategy for the effective separation of bitumen from low grade (< 10 weight percent bitumen) Utah tar sands by a hot water process differs significantly from that used for the processing of high grade (> 10 weight percent bitumen) Utah tar sands. Excellent separations (coefficient of separation = 0.9) can be achieved for high grade Utah tar sands by intense hot water digestion followed by a modified froth flotation step. Such a technique is ineffective for low grade tar sands. In order to change the characteristics of the low grade tar sand an attempt was made to enrich the bitumen content of the feed to greater than 10 weight percent by recycle of bitumen concentrate to the digestion stage. However the quality of the separation was not improved under these circumstances. Similarly feed enrichment by heat treating the low grade feed with recycled concentrate prior to digestion did not improve the separation. More successful separations of low grade Utah tar sands were finally achieved by modification of the viscosity of the low grade bitumen with controlled addition of diluent. These results of the hot water separation tests and variations in the quality of separation are interpreted in terms of the physical properties of the bitumen and the surface bonding forces operative at the bitumen-sand interface.

Jan 1, 1979

By A. Pinches, R. Winby, P. J. van Staden, M. K. Rhodes, P. C. Miller

This paper is a progress report on the commercialization of using bioleaching for base-metal concentrates. The paper focuses on bioleach processes for recovering copper from chalcopyrite and nickel/cobalt from pentlandite/pyrrhotite. Data is discussed from pilot-plant trials in which an overall recovery >95% was obtained for the bioleaching of copper from chalcopyrite. The pilot plant was operated in closed circuit with solvent extraction and electrowinning circuits for final metal recovery. For the bioleaching of nickel and cobalt from pentlandite/pyrrhotite, an overall recovery of 97% was achieved. Precipitation routines were used to produce a final nickel/cobalt product. The pilot plants were capable of treating a few kilograms of concentrate per day. Prominent features in the design of a 1-t/day (1.1-stpd) copper-bioleach demonstration plant for the treatment of chalcopyrite concentrate are discussed. The plant, which is now under design, will be constructed and operated based on the results obtained from the laboratory pilot-plant campaigns. Issues of scale-up for the demonstration plant, together with integration into upstream and downstream processing, are also addressed. Independently derived capital and operating costs are presented for a possible commercial plant. These cost studies indicate the principle economic issues in considering the application of bioleaching to the extraction of base metals. The benefits of bioleaching complex concentrates that are not amenable to physical beneficiation and economic treatment by conventional smelting are highlighted. Issues, such as the environmental aspects, that illustrate the benefits of bioleach technology are given.

Jan 1, 2000

By D. Leppert

Clinoptilolite zeolite may offer attractive, cost-effective alternatives for remedial cleanup of old minesites, smelters and other sites with heavy metal contamination. Previous research demonstrates the relatively strong affinity of clinoptilolite for numerous metals and clinoptilolite displays a particularly strong affinity for lead (Loizidou and Townsend, 1987), one of the most toxic and problematic heavy metals. Since clinoptilolite can also selectively absorb some radionuclides and organic compounds, it may offer practical solutions to a wide variety of environmental problems.

Jan 1, 1989

By J. den Drijver, M. Opahle, R. Inderst

Safety reasons render necessary the advanced calculation of the amount of methane degassing from a longwall in the scope of the ventilation planning of mines. Today empirical methods, which are based on observations of operational procedures, are used for the calculation of the amount of methane. Despite of constant improvement those calculations are not always sufficient. In particular calculations which are based on operational facts but not proved by experience are not reliable. Most of all these calculation procedures lack physical-analytical descriptions of the procedure itself, presenting only the effects on important parameters such as the distance between seams in the roof or floor or gas pressure. Tschersich [Tschersich 961 developed an analytical model for an advanced calculation by analysing the degassing of seams in the roof and floor and the physical parameters of gasflow. This model might correct the lacks of existing procedures and improve the precision and reliability of additional calculations. The model simulates the emission record in seams of the roof and the floor. It takes into account not only a multitude of parameters such as the distance to adjacent seams and gas pressure but also the depth of seams, gas content, rank of carbonification, rock temperature, face advance rate, initial and succeeding mining and the face length. In order to comprehend and to verify those correlations we extended the model of Tschersich and programmed this enlarged model using the computer language C++. Aim of this research is to guarantee a much higher accuracy in calculating methane emission caused by mining. The improved planning is expected to result in more safety and better prevention of high methane con- tent in ventilation as well as in a better use of the capacity of the mining equipment. The application [Drijver, lnderst 961 of the ex- tended model will also be very useful in the course of research projects as it allows computer simulation, i.e. in-situ research can be extensively limited or even replaced.

Jan 1, 1997

By G. P. Richards

RIP is the process of recovering uranium from an unclarified slime pulp which comes in contact with a moving bed of ion exchange resin, T e sand-slime separation of the acid-leach slurry is accomplished through the use of cyclones and spiral, akins type classifiers. Course sands are discarded to tailings and the combined slimes and leach liquor become the IX feed. Uranium in the IX feed is absorbed on the resin and after exhaustion the barren pulp is directed to tails, Following the uranium exhaustion cycle an eluant solution passes through the resin bed stripping the uranium from the beads, The uranium is precipitated from the clarified pregnant eluant, filtered, dried and packaged for shipment to the AEC, Normally, the ore received at the Mines Development plant is a loosely cemented sandstone containing small quantities of clay and bentonite, The ore is easily crushed and requires only a 1/3 load of rods in the rod mill to reduce the ore to grain size, Very little of the ore is recirculated by the 42" spiral classifier.

Jan 1, 1958

By Bruce A. McKinstry

Introduction For many major mining projects the time frame from initial planning to production can be measured in decades. Hecla&apos;s Silver Shaft project, scheduled to go into production by the end of this year, includes a complete surface facility, shaft with an ultimate depth of 2.4 km (7,700 ft), complete ore pass and loading pocket system, and 610 m (2,000 ft) of development drifting and stope preparation. The project was conceived in the fall of 1979, and the duration of a mere four years from conceptual engineering to production is testimony to what can be accomplished when a mining company and a contractor work as a team rather than developing into two warring camps, as often happens. Engineering In 1979, Hecla Mining Co. awarded a contract to J. S. Redpath Corp. to perform feasibility investigations and design engineering related to a proposed new shaft facility at the Lucky Friday Mine. The Lucky Friday, in Mullan, ID, is a major producer of silver, as well as significant quantities of lead and some zinc. In late 1979, stoping was in prog-

Jan 10, 1983

By Patrick Doig, Ross Webb

The Bradshaw Section 5A Interceptor involves the construction of two miles of 108-inch, finished diameter tunnel in dry soils. Excavation is generally by Lovat TBM with ribs and lagging support. The tunnel is beneath a recreational parkway and stringent measures have been enacted to preserve the parkway and minimize disruption to the neighborhood. Apart from these constraints, the project would have been unremarkable but for the intervention of CalOSHA and the local fire department who ordered extraordinary fire protection measures. The paper discusses the cause and effect of these measures and comments on the potential repercussions for other projects.

Jan 1, 1999

By B. S. Crocker

Introduction Pebble mill grinding can be defined as wet or dry grinding in a tumbling mill with pebbles used as grinding media instead of metal balls. To clarify the terminology, which may differ in the various mineral industries, it is essential to point out the differences between grinding with partially sized and carefully sized grinding media. When grinding with partially sized media (limited top size only), sizing is usually the setting of the primary crusher and there is no bottom sizing-all fines, chips, sand, and small sizes are included. This is often called run-of-mine or primary autogenous grinding. In this case the entire crusher discharge is fed into the mill and part of it becomes "charge" and the rest is "sand feed." When grinding with carefully sized media (i.e., media that is sized both at the top and bottom of the size range), no fines or chips should be present in the charge to the mill. This is pebble milling and the grinding media consists of ore, rock, Danish pebbles, gravel pebbles, or ceramic pebbles-media that is appreciably lighter than steel balls. The grind¬ing charge is fed to the mill to maintain a load and it does the grinding usually on a classified sand product of suitable size. If the grinding media is the same as the raw material being ground, this type of grinding is also called secondary autogenous grinding. Pebble milling was in common use in the gold mines of South Africa in the early 1900s. It is by far the oldest form of autogenous grinding. It may be used to grind crushed ores from a maximum size of about -% in. to all -10 µm. Pebble milling differs from "run of mine" grinding in many ways, but two big differences are: I) The ore itself is crushed to approximately t/4 in., or it may be further reduced to 8 or 10 mesh in a rod mill or fine crusher. 2) Then carefully screened ore of the correct size is placed in one or more stages of pebble mills to grind the ore to its desired final size. The media size is carefully selected to be the most efficient for the particular size reduction required in each stage. This is a precise practice, and pebble mills can be designed as easily and accu¬rately as can rod mills or ball mills by those skilled in the art. A pebble mill is a rotating cylinder in which the grinding media has been carefully sized for the job in hand. If the mill is doing coarse grinding, the media will be correspondingly large and the mill might be called a primary (or intermediate) pebble mill or a lump mill. If it is to do fine grinding, the media selected is proportionately smaller and the mill would be called a secondary or tertiary pebble mill. The media itself is normally rounded pebbles made from screened ore from the primary-crusher discharge. The charge could be rounded pebbles of the correct size removed from a primary autogenous mill, or the pebbles could be carefully sized gravel, sized beach pebbles, or sized flint pebbles. Usually the specific gravity of a pebble is from 35 to 55% of that of steel balls. It commonly varies from 2.66 to 4.2, depending on the specific gravity of the ore. Primary pebble mills, or lump mills, would be charged with pieces of rock up to 10 in. maximum and 5 in. minimum and would grind crusher discharge with a maximum size of 1/4 in. on hard ores and 3/8 in. on softer ores. Secondary pebble mills could be charged with pieces of rock screened on 4 x 4-in. square mesh and retained on 1 1/2 x 1 1/2 in. These mills would grind material with a top size of 8 to 10 mesh. Tertiary pebble mills could be charged with screened rock that would pass 3 x 3 in. and be retained on 1 x 1 in. and grind 35 to 48 mesh sands. Principles of Operation Media Size To operate a pebble mill efficiently it is imperative that great care be taken in screening the rock feed that is fed into the mill to round up into a range of pebble sizes that are suitable for grinding of the sands that are also being fed into the mill, having regard to the top size and the average size of such sands. Since most mill operators know from experience the correct size of steel balls to be used in a mill to handle different sizes of sand feed, it is convenient to relate the pebble size to a ball size. If the correct ball size is not known, it is relatively simple to conduct batch laboratory tests in 12- to 18-in. laboratory mills to determine the optimum size of steel ball. Also, Bond and others have published formulas for calculating the optimum ball size. When the correct size of the individual steel ball is known, then a pebble of the same weight will perform the same grinding if used in the proper size of mill and under the proper conditions, which will be defined later. This media size, as defined by the average weight of the individual pieces, is most important. The following tests will serve to clarify this point. Laboratory Tests Using Steel Balls or Pebbles. Several labora¬tory grinds were made to compare a given size and weight of steel ball with a pebble of the same weight but larger size, and of the same size but lighter weight. The following loads were used in the 12-in. laboratory mill: All 1 1/4-in. steel balls weighing 122 ± 10 g. All 1 3/4-in. pebbles weighing 123 ± 5 g. All 1 1/4-in. pebbles weighing 45 ± 3 g. To equalize capacity, the test with the steel balls was run only 34% as long as the tests with pebbles. In each case, 2,500 g of primary sands were ground at the optimum gravity for the media being tested at a speed 78 1/2 % of critical speed, and for 170, 340, and 680 revolu¬tions for the steel balls, and 500, 1,000, and 2,000 revolutions for the pebbles. The first test is summarized in Table 74 by showing the 80% passing size in microns for the feed and for each of the grinds. Two other tests are summarized in Table 75 showing the screen analyses

Jan 1, 1985

By Schebek, J. Warsen

"Data and information from sustainable development (SD) reports can be seen as a promising and easily accessible source for an Life Cycle Assessment (LCA), i.e. for generic Life Cycle Inventory (LCI) data in particular. The reliability and comparability of LCA results crucially depends on the quality of LCI data, that is defined by specific normative requirements. In parallel the GRI (Global Reporting Initiative) provides a set of guidance documents for enhancing the quality, rigor, and utility of SD reporting with specific reporting principles that address similar issues on a company level comparable to LCI data quality requirements on the process level. In order to assess the general suitability of the fundamental reporting principles for LCI data quality purposes selected reports from mining and minerals (M&M) sector are assessed within a detailed analysis."

Jan 1, 2005

By Yehia El-Ibiary, M. P. Evans

One way of increasing conveyor systems productivity is by monitoring the key parameters in the systems. In this paper, a new line of smart bearings will be presented and discussed. The new bearings are capable of monitoring temperature, vibrations, and belt speed for early detection of potentially serious problems. The new smart bearings have built in sensors that are carefully integrated and protected for long life service. These bearings are going to be the key to increasing the up time of belt conveyors in the future.

Jan 1, 1996