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By William L. Rose

Production scheduling is an integral part of intermediate- and long-range open-pit mine planning, affecting equipment selection, manpower requirements and project economics. The development of mining phases, or pushbacks, is discussed in conjunction with generating the best spatial extraction sequence. An approach to scheduling production from these mining phases is then described. Using computers and a production scheduling algorithm, the impact of cutoff grade and advanced stripping policies can be evaluated through sensitivity studies to maximize the return on project investments.

Jan 1, 1985

By Richard F. McFarlin

INTRODUCTION Phosphate, one of the three major elements essential for all living plants and animals, has been mined in Florida for over a hundred years. Comprising roughly 80% of the U.S. total and 25% of the world's supply, the bulk of the 35 to 40 million annual ton output is converted to chemical fertilizers. With the exception of one mine in north Florida near the Georgia state line, today's mining activities are centered in the middle of the peninsula just east/southeast of Tampa in Polk, Hillsborough and Hardee counties. These "bone valley" deposits extend into Manatee and DeSoto counties, but there is little active mining there as yet. Because strip mining is, perhaps, the ultimate environmental insult and because Florida has a proactive environmental community, it is not surprising that the mining of phosphate rock has become increasingly controversial. This paper describes how phosphate rock is currently mined, the environmental problems presented by mining and processing the rock, and some mitigating technologies being employed to answer such problems. THE PHOSPHATE DEPOSIT AND ITS EXTRACTION Florida's phosphate deposits containing the calcium phosphate mineral, carbonate-fluorapatite, are between ten and fifteen million years old. The typical "bone valley" matrix is 15 feet thick and lies under 20 to 30 feet of overburden.(Fig. 1) Both the sandy overburden and matrix are unconsolidated and can be removed with standard 45 to 65 cubic yard, walking electric draglines. After removing the overburden, which is windrowed nearby, the dragline operator casts the matrix into a "slurry" pit where it is broken up by high pressure water monitors. Pit pumps (with boosters where necessary) transport the matrix slurry through 16 to 20 inch pipelines to a washer where the three components of the matrix (sand, clay and apatite) are separated. The phosphates contained in central Florida matrix are approximately half pebble/half flotation feed, through the pebble ratio decreases as the industry mines southward. Again, the matrix is roughly equally divided among sand, clays and apatite. The phosphatic clays, 75% of which are less than one micron in size, leave the washer as a 3 to 5% colloidal suspension. The impoundment of these waste clays is one of the environmental challenges to be discussed later. The sand (silica) is separated from the similarly sized phosphate particles by a double float process (fatty acid followed by a reverse mine or cleaner float), and the sand tailings are then pumped to disposal or reclamation sites. The apatite flotation product is combined with the screened phosphate pebbles and stacked to dewater before shipping.

Jan 1, 1992

By Kim W. Wright

Introduction Mining operations require maps for each phase of project development. Engineering plans, cross-sections, and isometric drawings are also needed. Maps are used for geologic interpretation, reserve estimation, permitting, property acquisition, site studies, development work, and production. Maps and drawings are essential to mining. They provide needed information. Generating these products, however, requires many manhours. The filing and organization of maps and drawings is cumbersome, due to their size. Major map changes can necessitate the production of entirely new documents and, thus, additional manhours. The volume of maps and drawings generated in the life of a single project can be extensive. For example, some utility companies have data bases containing more than a million individual maps (one reported eight million). These problems were considered necessary evils in the past. Now, with the automation of map and drawing production, improvements can be realized. Computer-aided mapping and design offers a new approach for the production, management, and storage of drawings and maps. This approach promises benefits in time management, productivity, efficiency, and flexibility. In all economic projects, the bottom line is cost reduction. And implementing computer-based mapping and design techniques can lower costs and increase project profitability. AM/FM/CAD/CAM Automated Mapping/Facility Management (AM/FM) and Computer-Aided Design/Computer-Aided Manufacturing (CAD/CAM) are becoming buzz words in the engineering world. Most relevant to mining are the concepts of AM and CAD. These terms relate to the application of computers, specifically computer graphic technology, to mapping and design. CAD refers primarily to the design of components and structures in two and three dimensions. But it can apply to the three dimensional modeling of mine workings, ore bodies, and geologic structures AM refers to the automation of conventional map production. AM/CAD systems use computers to store, manipulate, produce, and update drawings and maps in two and three dimensions. Ideally, the calculating capabilities of computers are also used in conjunction with design and drawing generation, offering capabilities not available with conventional, manual mapping and design processes. To better understand concepts associated with AM and CAD applications, the understanding of a few computer-related terms is necessary. Table 1 explains some of these terms. System Features The capabilities of AM/CAD systems are based on viewing transformations. These are the basic, manipulative tools by which AM/CAD packages generate visual representations of data. Examples include the rotation of a three-dimensional object through space, the expansion or contraction of maps to fit a given scale, enlargements of small areas on maps or drawings for detailed viewing, and the generation of cross-sections from three dimensional data. AM/CAD systems incorporate data base management in their architecture. This allows a user to modify, move, delete, or manipu-

Jan 6, 1985

By Wayne Taylor, Martyn Dawborn

Simulation modeling of portions of two platinum mines using General Purpose Simulation Software (GPSS/H™) is presented in this paper. Both mines, located in the Bushveld Igneous Complex PIC) of South Africa, exploit Merensky and UG2 reef horizons, which are processed separately and therefore handled individually from the stope face to surface, requiring duplication of storage arrangements and batch operation of transport facilities. The first simulation assignment concerns the upgrading of a shaft system operating exclusively on Merensky ore, to hoist UG2 ore and increase production. The second assignment comprises a simulation of rock flow from the stope face to surface by way of tramming, inclined conveying and vertical hoisting. Development ends and stope boxholes were modeled down to individual hoppers (cars) demonstrating the versatility of the GPSS/H™ language.

Jan 1, 2002

By Joseph Cervik, Fred Garcia

Gob holes are routinely used by the mining industry to vent methane from gobs and to prevent it from entering the mine ventilation system. In some cases, flows from gob holes are measured by centering an anemometer on the end of the discharge pipe. These measurements are erroneous and tend to be high by as much as 30%. The Bureau of Mines determined correction factors (method factors) for anemometer measurements taken in this manner. Method factors for 10.2, 15.2, and 20.3 cm (4, 6, and 8 in) ID pipe are 0.68, 0.71, and 0.78, respectively. Comparisons between horizontal and vertical flows indicated no significant change in method factors. Consequently, the method factors for horizontal pipe flows can be applied to vertical upward flows.

Jan 1, 1987

By W. Bosmans

The European Commission published its Communication of the Thematic Strategy on the sustainable use of natural resources ("Resource Strategy") on 21 December 2005. The Resource Strategy aims at reducing environmental impacts associated with resource use - called decoupling - in a growing European economy and worldwide. The impacts of unsustainable resource use include e.g. climate change due to fossil fuel use, land use and environmental degradation due to mineral extraction and processing, or overexploitation of soil and fish stocks. To decouple environmental impacts from economic growth, a life-cycle approach is adopted. It means that the environmental impacts are taking into account at each stage of the life cycle of a resource, avoiding that negative impacts are shifted to other environmental media, to other stages of the life cycle, or to other countries. Key to achieving decoupling are three factors: - More value - creating more value while using fewer resources (?resource productivity?); - Less impact - reducing overall environmental impact per unit of resources used (through ?cleaner? technologies and consumption pat-terns); - Better alternatives - substituting currently used resources with better alternatives. The paper focuses on the implementation actions of the Resource Strategy in particular related to the minerals industry: 1. The Data Centre on natural resources; 2. Indicators to measure progress; 3. The involvement of economic sectors to take concrete actions; 4. EU Member States involvement, focusing on resource uses with the most significant impacts; 5. The International Panel on the sustainable use of natural resources, set up together with UNEP. With its 25 years time horizon and its wide approach the Resource Strategy will have a co-ordinating function to ensure enhanced coherence and efficiency. The challenge will be to integrate this approach into all policies and decision-making.

Jan 1, 2007

By Rodolfo V. de la Cruz

This paper describes the development of a new method and device for determining the in-situ mechanical properties of rock masses. The method involves a self-recording mechanical deformation gauge for sensing-recording she deformation of the borehole wall when loaded hydraulically. The self-recording feature of the gauge eliminates the difficult technical problem of transmitting signals over very long cables for measurements at great depths. Adopting a mechanical gauge instead of electronic, electrical, optical or grid techniques eliminates delicate instrumentation and installation problems. Moreover, mechanical gauges are inherently rugged and suitable for use in severe borehole conditions including very high temperatures. The technique was tested in limestone, basalt and granite specimen. The calculated mechanical property values for 1 the tests agree with those obtained by conventional testing methods. The self-recording mechanical deformation gauge has a minimum reading of 50 micro inches (1.27 x 10-3mm), comparable with electrical resistance strain gauges, capable of reading deformations over a range of 0.25 inches (6.35mm). The sensitivity, ease and accuracy of the method recommends it highly for in-situ rock modulus measurements.

Jan 1, 1980

By C. E. Jordan

The Bureau of Mines investigated a simultaneous elutriation and flotation technique for separating polyethylene terephthalate (PET) from polyvinylchloride (PVC). The Tuscaloosa Research Center, through a cooperative agreement with a recycling company, devised an elutriation-flotation method for beneficiating the mixed heavy plastics portion of municipal solid wastes which is composed of polystyrene (PS), PET, and PVC. A sodium carbonate brine was used to remove the lighter PS from the heavier PET and PVC. Over 98 pct of the PS was recovered in a high purity PS concentrate containing 99.7 pct PS, The remaining PET and PVC mixture was washed to remove the brine salts that would be harmful to the flotation process. The clean PET and PVC mixture was conditioned in a solution of 45 g/t gelatine and floated in a short (l-m) column flotation cell in an upward flow of water. In a single flotation step, over 75 pct of the PET was recovered in a high purity product containing 99.8 pct PET. The bubbles attached to the PET lowered the effective density of the PET-bubble agglomerate and allowed successful separation of these agglomerates from the PVC plastic pieces. This method separated two-thirds of the mixed plastics fraction into high purity PS and PET products suitable for recycling and left only one-third of the plastics in the mixed plastics product.

Jan 1, 1992

By S. Makni, F. Wang, A. Rosa, B. Klein, C. Saud, R. McIvor, A. Kumar, C. Gagnon, D. Gong

In response to the Natural Resources Canada “Crush It Challenge”, Corem partnered with the University of British Columbia and led a project to develop and demonstrate the use of high-pressure grinding to replace the workhorse of the industry, wet ball milling, with high-pressure grinding. Two plant case studies, a small tonnage gold recovery operation, and a large tonnage copper recovery operation, were carried out. Plant circuit performances were compared to pilot plants operated on the same circuit feed set up to represent the novel equipment and flowsheet that was developed to produce separation circuit feed. Numerous obstacles to industrial implementation of highpressure grinding in this role which were recognized at the outset of the work were successfully addressed. In both cases, comminution equipment energy savings alone, and final stage total circuit energy savings, exceeded 60% and 50%, respectively. Downstream mineral separation performance was the same or better.

Mar 2, 2022

Little knowledge is available that considers the effects of continuous miner position on the possible respirable dust exposure of the remote mining machine operator. Such information could be very useful for increasing the awareness of the remote operator as to those parts of an extended cut that generate higher levels of respirable dust. This data could be used to develop guidelines for positioning the remote operator to reduce his potential exposure. This work details the effects of continuous miner position on dust levels measured on the machine and at the remote continuous miner operator location.

Jan 1, 1998

By J. P. Golightly

The structure and occurrence of nickeliferous laterite profiles are described and explained in terms of mineral solubility and drainage conditions. Complete profiles, from top to bottom, include: limonite zone; nontronite or silica zone; and saprolite zone. The middle zone is present only where drainage is sufficiently slow to allow saturation conditions to build up with resulting quartz or smectite precipitation. This precipitation may occur in any climate at a water table or in tropical climates with a long dry season. The degree of serpentinization of the laterite parent rock is important in determining the nature of the saprolite zone. Unserpentinized peridotite produces saprolite ores with hard residual rock cores, nontronitic or amorphous saprolitic rims, and fracture fillings of garnierite and quartz. Ser-pentinites yield relatively homogeneous serpentine saprolite, with minimal quartz or garnierite.

Jan 1, 1979

By Patti J. Best

The Southern Powder River Basin (SPRB) now commands 30% of the US utility, coal market due to the region's low mine production costs, competitive rail rates and low sulfur content. In 1997, production exceeded 240 Mt (265 million st). This was an in¬crease of 104 Mt (115 million st) since 1989 and 4.5 Mt (5 million st) above 1996. Continued growth is expected as the second phase of the Clean Air Act Amendments (CAAA) approaches. This growth will be the greatest in the southern part of the Basin where coal quality is higher. Coal characteristics SPRB coal is classified as subbituminous due to its low heating value and high moisture content. The coal is characterized by low sulfur and ash contents, low ash fusion temperatures and high reactivities. In 1997, the average heating content was 8,593 Btu/lb, with an average sulfur and ash content of 0.79 lbs S02/million [ ] Btu and 5.13%, respectively. The distinguishing characteristic of SPRB coal is its low sulfur content. Most SPRB coal contains less than 1.2 lbs S02/million Btu. This is the approximate definition of "compliance" coal for Phase II of the CA AA. Much of the coal, particularly in the southern part of the Basin, is referred to as "super-compliance" coal due to SO2 contents of between 0.4 and 0.7 lbs SO2/million Btu. The SPRB is divided into three geographic clusters based on coal quality. Mines located in the southern part produce coal with the lowest average sulfur content and highest heating content, almost 400

Jan 1, 1998

By D. C. Lynch

While silica ores are generally considered to have little value, those with exceptionally low B and P content have, potentially, significant worth if processed for use in photovoltaics. The sales value of a cubic meter of ?run of the mill? silica sand is $42 per cubic meter (retail and delivered). If the silica sand can be used to produce solar silicon, its value after processing is $34,000 per cubic meter. Factors that impact the suitability of silica for direct processing in production of photovoltaics are examined.

Jan 1, 2010

By Ing. Ludwig Schlebusch

The significant growth of the world population and its demand for an increasing standard of living leaves no other choice than continuously augmenting industrial production and making available steadily greater quantities of raw materials at still better qualities. Therefore, any raw material has to be utilized to the greatest possible extent and processed at optimum economy on large mechanical equipment. The layout of processing facilities of large throughput rates can be based on multiple or single lines. The latter enables the application of large machines of optimum size. Proven equipment for homogenizing, classifying, separating superfine material, sorting and dewatering are-now available in optimum sizes. By the use of these large machines operating cost of pit coal preparation plant can be significantly lowered by reducing the specific requirements regarding space, capital investment, energy, operation and maintenance.

Jan 1, 1980

By G. E. McClelland

In recent years exploration and development of low-grade sulfide precious metal ore deposits has increased. Low- grade ores are usually processed using conventional heap leach cyanidation methods. The potential for acid mine drainage from spent sulfide ore heap leached residues remains a concern even though the processed residue is stacked on an impervious liner system. It is therefore of critical importance to evaluate methods for long term prevention of acid mine drainage from sulfide heap leachable ores during the precious metal recovery process rather than mitigation during the closure and reclamation phase. This paper discusses two simple AMD prevention options for the recovery process phase. Laboratory evaluations were made using a modified humidity cell kinetic AMD test method on two low-grade sulfide ores without addition of an alkaline component and on the same ores with natural limestone or acid neutralizing oxide ore blended with the feeds before kinetic testing. Laboratory results are discussed in detail and demonstrate that blending an acid neutralizing component with sulfide ore effectively prevents the production of acid from the processed residue.

Jan 1, 1996

By George E. Edwards

Pacific Rim markets for export coal already represent a larger market than the total tonnage imported into the European Community countries and they will continue to expand. The largest importers will continue to be in the sector comprising Japan, Korea, Hong Kong and Tai- wan. It is likely that the total Pacific Rim markets will reach 206 m.t.p.a. by 1990 and 290 m.t.p.a. by 2000, with the major growth in steam coal demand. Australia has an efficient coal industry, represents a stable long term source of supply and is favourably situated geographically to continue to be the largest single supply source.

Jan 1, 1982

By Arthur M. Ribe

In my experience, nothing helps me better to get off to a good start in preparing a paper or a talk than a copious consultation with a comprehensive dictionary. I also feel defining the perimeters of a particular subject is helpful to the listener and reader. Sometimes thus precisely defining even the most common of words is helpful. Our general topic this morning as all of you know is "Transportation of Industrial Minerals." The definition of transportation given by the dictionary which I think is appropriate here is: "Systems and modes of conveyance of persons or goods from place to place." Our preceding panelists have outlined for you the state of the art inso¬far as systems and modes of conveyance from place to place are concerned today via rail, water and motor. My assignment is somewhat different as indicated by my topic, "The Traffic Manager in an Industrial Minerals Operation."

Jan 1, 1969

By Nicholas S. Lynn

Introduction Borne out of the need for reductions in capital expenditure and increased production, several new and innovative carbon systems have been developed for small precious metal heap leach operations throughout the United States. Perhaps the most important aspect of these systems is the carbon column. Though diverse in design, these columns can be categorized into three basic types. The first is known as the gravity flow type or Cortez type. As the name indicates, solution flows via gravity, throughout 4 to 6 columns which are arranged in a normally stepped con- figuration which is conventionally upflow in design. The second type, known as the vertical column, is an arrangement whereby flow is established through pressurization in an upward manner, throughout 4 to 6 columns in a vertically stacked configuration. This arrangement is typically intended for use with small portable heap leach operations and employs a semi-continuous mode thus preventing gravity from occurring. The third type and newest development in carbon columns is an arrangement whereby the solution flows throughout 4 to 6 columns placed in a side by side configuration and pressurized by a single feed pump (Figure 1). A unique aspect to the third type, is that the adsorb and desorb cycles are accomplished in the same column, due to a fixed carbon charge. An in-depth analysis is warranted due to numerous advantages of this arrangement, and is therefore the subject of this paper. Advantages and Variations One advantage to the third type of carbon column is the fact that initial capital expenditures and operating man- power requirements are reduced. Another advantage is that the system can be made fully portable up to a 0.0315 m3/s (500 gpm) capacity. Systems of this nature are operational at several sites. Above this flow rate, the system's portability is one which can be maintained, but disadvantages (i.e. larger diameter carbon column and greater weights) far outweigh the advantages. There are several variations in each of these systems which allow for unique operation. For example, carbon columns made highly portable, can be moved from unitized heap leach operations to central stripping facilities. Although this method has been used in Colorado, transportation of these units has been known to be quite cumbersome. If distances exceed 5 km (3.2 miles) then special front-end loaders are required. This limits heap locations to within 5 km (3.2 miles) of the central processing facility. Another example transports the carbon charge from the heap leach locations to a centralized processing facility; this method is quite effective. For the past 5 years one mine has employed this technique of transporting carbon in 907 kg (1 ton lots), in DOT containers, towed by company pick-ups. This operation uses a vertical column with a 907 kg (1 ton) carbon charge. A third example uses static carbon columns with fixed carbon charges. Carbon Adsorption System The carbon adsorption system (Figure 1) is fed by a single preg solution feed pump. This feed pump pushes the preg solution through all four to six fixed charged carbon columns, which are on line. The sequencing of the carbon columns is achieved using valves. Expansion of the carbon charge is dependent upon the carbon selected. The carbon typically used is a 6 x 12 mesh size, with a nominal flow rate of 0.00135 - 0.00138 m 3/s (22-25 gpm) per square foot of carbon, based on a 40% bed expansion. With 8 x 16 mesh size,

Jan 1, 1987

By H. G. Fleshman

Thousands of years ago, Chinese water well drillers developed a technique for punching holes in the ground by lifting massive metal bits and letting them fall against the rock. With diligence, they could pound away about 2 feet a day. The Chinese drillers pounded holes in the ground this way for almost 2000 years. In the 1860's, French water well drillers developed a perforated bit moistened by fluids pumped into the hole through a hollow rod. The fluids carried the cuttings from the hole and spared the Frenchmen the task of bailing them out by hand.

Jan 1, 1986

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