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By A. M. Tunstall

Blasting is commonly viewed separately from mechanical handling and crushing. This view is misleading because the degree of fragmentation achieved by blasting can have a significant effect on the efficiency of these processes and, hence, on the overall cost of the mining operation. In this paper, aspects of blasting and crushing and their interaction are examined. A case study is also presented that dramatically illustrates the influence of blast fragmentation on subsequent processing and on the financial implications involved.

Jan 1, 1998

In a world dependent in part on the consumption of depletable natural resources, development of new areas of mineralization is a necessity for replacing those reserves. Exploration, which is the initial task of replacement, is an information-gathering process which supplies input for management decisions on mine development. If the demand for resources is the driving force of exploration, then the scientific basis for its pursuance is the hypothesis of anomalous mineralization in a metallogenic province, which is tested by measuring physical characteristics of natural phenomenon. The resulting data are reduced, analyzed, and interpreted to locate expressions or responses associated with possible ore bodies. The process is, in fact, repeated in ever increasing measurement detail to increase the accuracy and precision of information for decision making. Exploration ceases when management makes the decision to develop a mineralized area, to hold a property for more favorable market conditions, or to drop a property because it is not economically viable.

Jan 1, 1979

By Sheldon P. Wimpfen

SHELDON P. WIMPFEN The measure of the success of any mining operation is the size of the difference between sales realization and cost of product, including operating, sales, administra¬tive, capital and others. Evaluation of a mining project necessitates projecting costs and sales realization as accurately as possible. Possible variations in specific cost elements and sales prices must be considered. To accomplish this, project studies should include giving effect to possible fluctuations to determine the break¬even points with varying costs and prices. Development of cost data is never an easy task. Mining is characterized by a great variety of conditions which result in still more variables. Achieving realistic figures as of any specific time involves consideration of changes, which may be frequent, in labor-contract terms and equipment used, variations in working condi¬tions and mining practices, and changes in mineralization and metallurgy. The purchasing power of the dollar, which has been declining persistently, also affects the situation at any given time. The only thing that can be said of costs, with certainty, is that they will change. With this in mind, the "guideline" data in this section are offered for the use of the mining engineer. It was provided for the most part by representative companies, whose contributions are gratefully acknowledged. In reviewing the tabu¬lations and other material it is of course necessary to remember that the data presented are valid only for the time periods specified, and will change with changing economic conditions in any other. 31.1-CAPITAL COST OF PLANTS Plant capital costs are set forth in Tables 31-6 and 31-7 by year of construction. To estimate capital cost of plants built in future years, various cost bases and indexes are utilized. Design and Construction Manpower: Monthly Salary Ranges, January, 1970 Project manager $1,400-82,600 Project engineer1,000- 1,500 Project design engineer1,050- 1,800 Senior engineer1,000- 1,700 Senior design engineer1,100- 1,700 Senior engineering designer1,000- 1,300 Layout draftsman750- 1,000 Detail draftsman650- 1,000 Material engineer900- 1,400 Construction-project manager1,500- 2,500 Project engineer1,500- 2,500 Construction superintendent 1,500- 2,500 A rule of thumb in design work is one man-month per drawing. The number will vary for each specific plant. For a recently constructed 30,000-tpd (tons per day) copper concentrator, 1,800 drawings were made. Design should provide for the addition of milling units when these may become justified in relation to investment markets and life of the deposit.

Jan 1, 1973

By Cynthia M. Walck, S. K. Grant, R. D. Hagni

The Post Gold deposit is located in the northern part of the Carlin trend. The mineralization at Post occurs in proximity to a Jurassic-Cretaceous composite stock. Most of the gold at Post is hosted by non-metamorphosed calcareous siltstone and highly altered diorite, adjacent to the low grade skarn. Endoskarn, exoskarn, hornfels and marble are developed outward from the intrusive. The skarn is composed dominantly of diopside, tightly intergrown with gannet, k -feldspar, and sphene. The highest grade gold values are adjacent to the skarn, which acted as a permeability barrier to fluid migration. Post is the first Carlin-type deposit at which a skarn has been recognized to play a significant role in the localization of gold.

Jan 1, 1990

By Robert C. Dunne, Jeffery P. Vaughan

The Archean ores of Western Australia are in total the largest producers of gold in Australia. In addition to numerous small and medium sized deposits, the province also contains the giant Kalgoorlie Golden Mile deposits. A variety of different gold ore mineralogical associations has lead to the development of a number of different processing routes for both refractory and non-refractory ore types. Intense weathering and lateritization of Archean greenstones in the semi-arid Yilgarn region have resulted in the development of a deeply oxidized profile (60-100m) above most sulphide orebodies. Residual and re-deposited supergene gold within iron oxide/silica gangue of this zone responds well to CIP, CIL, heap and vat leaching techniques. Although gold is easily liberated in principal from oxidized gangue, in practice recoveries are sometimes affected by iron oxide coatings on gold grains, and by clay minerals which can interfere with plant performance. Refractory ore types in the Eastern Goldfields fall into three main categories - pyritic, arsenopyritic and telluride-bearing. Pyritic ores may be either free milling or require roasting. The difference appears to depend largely on whether gold occurs along grain boundaries or fractures, which can be liberated by grinding, or whether gold occurs as inclusions within pyrite grains and therefore cannot be satisfactorily liberated by grinding. Arsenopyrite bearing ores are not well understood and are complicated by what appears to be a variable degree of gold solid solution, in addition to included gold. Gold occurring in complex gold-silver telluride assemblages has traditionally been recovered by roasting in the Eastern Goldfields.

Jan 1, 1987

By Victor F. Hollister

This first section of case histories of mineral discoveries, Vol. 3, covers some of the milestones in porphyry copper and skam exploration successes. It was during the era of these discoveries that large, complex exploration departments emerged as permanent adjuncts of large mining companies. The discoveries helped shape how and where exploration activity was conducted. Probably the most important factor in exploration success is management. Few management people are mentioned in this section or in any exploration history, yet the distinction between success and failure ultimately rested with the decisions they made. One of the most successful groups was initiated by Roger Straus and Herbert Brownell when they sought to make Asarco into an important metal producer. Relying on Clem Pollock and L.H. (Bill) Hart to identify and push worthwhile projects, the Asarco management remade the company. Asarco will benefit from exploration successes com- pounded by that team for years to come. Duval is an example of a management that decided to add metal production to its industrial minerals output. When Page Morris was president, that company opened three major porphyry copper mines and became an important factor in metals. Under the Monis management team, Duval became a leader in exploration. At the other end of the scale are managements that snatched defeat from the jaws of victory and by so doing changed the character of their companies in other ways.

Jan 1, 1991

By Osvaldo A. Bascur, J. Pat Kennedy

Large metallurgical complexes have more data than a small city and much of it is "real time," changing rapidly as internal and external conditions evolve. As corporations buy and sell assets and reengineer their staff, the structures and tools that were used to understand these data are lost. The lack of an integrated approach makes the profitability of metallurgical plants lag behind that of other industries despite technical advances that have occurred in recent years. This results in significant deterioration in the ability to maintain a "smart” operation. The solution is to use the sophisticated new tools built for the Internet so as to leverage information in a familiar browser format that people can use and understand. Combining real-time infrastructure with portal technology is becoming an accepted methodology. This paper introduces real-time portals and team sites to support decision making by work- groups which require both real-time and documentary information from manufacturing assets, vendors, head office and the Internet. Workers get insight from the overall process effectiveness index based on key variables such as losses due to plant availability, performance efficiency and rate of quality. Real-time portals and smart clients are part of any real-time performance management (RtPM) solution. Three case studies in large metallurgical complexes are presented. PLANTS ARE YOUR STRATEGIC HANDICAP Information technology is arguably one of the fastest moving technologies used by the mining/metallurgical industry. However, the business model for managing that

Jan 1, 2004

Projections of coal reserves in Central Appalachia are essential for long-term planning in the region. Annual production is declining in states such as Virginia. And minable reserves for the Central Appalachian coalfield are challenged by difficult geological, mining and market conditions. To project coal mining longevity in this region, interviews with mining companies were conducted to determine and assess technical and economic factors that affect coal seam minability. This information was ap- plied to seam and coal reserve data developed by state and federal governments. The results were analyzed to determine the effects of various factors on the overall minable coal reserve base.

Jan 1, 1998

By N. Edmonson

During the last 30 years, a dramatic increase in the supply of byproduct sulfur substantially reduced the share of the market held by Frasch-mined (non-by-product) sulfur in North America. Even though Canadian sulfur production is not discretionary, the geographic remoteness from the large US markets and the high transportation costs associated with delivering sulfur to those markets has meant that Canadian producers act like discretionary producers in many important ways. They have effectively replaced the US Frasch producers as the cost-marginal sulfur source to large US markets. Implications of this change in market structure include more volatile sulfur prices and longer sulfur price recessions.

Jan 1, 1997

By Klaus Böde

Within the national and international strategy of the German based construction company HOCHTIEF, the majority of its business units is equipped with the comprehensive software package ARISTOTELES. This software is a powerful business information system for all accounting and controlling related processes in medium-sized and large construction and other related companies. Due to the complexity of the software, time constraints, and limited financial resources an implementation of this software package requires thorough project management. In this paper the relevant elements of project management are outlined based on practical experiences gained during this international IT - implementation project. Special emphasis is directed to the identification and management of potential risks. In this case particular acknowledgement was given to the multinational nature of the project and modernization of the business. This includes thorough reorganization of the company, significant changes of job requirements, and substantial trainings for its employees. At the same time key success factors like knowledge transfer, adoption of Czech legal requirements, commitment of management, networked thinking, and integrated project planning come into play. The costs for implementation had to be carefully evaluated because the software was implemented in a country with a considerably low cost I price level. All these impacts to the business had to be managed within the scope of transformation of business and political environment from socialist to market driven economy.

Jan 1, 2002

By Atmesh K. Sinha

The market for thermal coal has recently been growing rapidly and it is projected to continue to do so in the foreseeable future. Both the national and international markets often demand high Btu low sulfur thermal coal in order to minimize the cost of utilization and meet the environmental restrictions. High quality thermal coal can be prepared to compete in the utility market by desulfurizing the high Btu midwestern coal and blending it with low sulfur western coal which is usually low in Btu content. The methods that can be used for optimizing the coal preparation plant operating parameters for physically desulfurizing coal is presented.

Jan 1, 1984

By Dapeng Zhang, Brij Moudgil, Shibo Zheng, Chunhui Feng, Wenyi Song, Wending Xiao, Patrick Zhang

The separation of dolomite from phosphate is the most challenging problem in phosphate mineral processing. More than 50 percent of the phosphate reserve in Florida contains too much dolomite to process using current industry practice. The current way of producing phosphoric acid requires less than one percent MgO in the phosphate concentrate as the feed material. The Florida Industrial and Phosphate Research (FIPR) Institute has collaborated with worldwide experts in the field to address this issue. As a result, the industry is now offered three feasible options. Option I entails three methods for reducing MgO content in the concentrate from the Crago process, including adding a dolomite depressant in the rougher flotation step, dolomite flotation of the cleaner concentrate, and scrubbing the cleaner concentrate in quartz sand, which could reduce MgO content in the final concentrate by 20 to 40 percent. Option II involves the crushing and grinding of high-dolomite phosphate pebbles followed by dolomite flotation at slightly acidic pH using a new collector that does not require phosphoric acid as a phosphate depressant, achieving a final concentrate analyzing less than 0.9 percent MgO at about 87 percent P2O5 recovery. Option III is a gravity separation technique using an innovative separation jig, and its full potential remains to be demonstrated.

By Brendan Parker, Joseph Skrypniuk

Boddington Gold Mine1 (BGM) commenced production in 1987 and is currently ranked as the second largest gold producer in Australia. In a strategy to improve plant efficiency, constraints to plant performance were identified and prioritised with a view to maximising benefit for minimal expenditure. After identifying that leach kinetics and circuit residence time were major constraints, the introduction of oxygen was identified as having the greatest potential for the delivery of sig­nificant cost benefits. The application of oxygen, initially by conventional tech­niques, and subsequently by installation of Atomaer's Filblast gas shear reactor, improved gold recovery, reduced the resi­dence time constraint and enabled higher mill throughput to be achieved. Additional benefits included operation at lower pulp densities and a reduction in reagent usage. A significant reduc­tion in unit operating cost resulted from these benefits. This paper quantifies the above benefits in a format accept­able to both metallurgists and accountants by integrating the findings in a techno-economic perspective.

Jan 1, 1996

By D. K. Grubbs

Red bauxites from Breadnut Valley, Clarendon Parish, Jamaica, are very homogeneous in texture. Bauxite minerals are uniformly distributed in a groundmass, the predominant grain size being smaller than l um (Figure 1 Although the deposits have a massive, non-stratified structure, they all seem to have been affected by postformational faulting which is evidenced by shear zones running subvertically through the deposits. These shear zones stand out very clearly because of a yellow staining along their faces. Often yellow zones, ranging from a few m to several cm in thickness, have developed. When the shear zones are cut at an angle, they appear as yellow veins. Near the surface of the deposits, yellow material forms shallow irregular lenses (Figure 2). In most cases, tree roots (hair roots), or their imprints, are associated with the shear zones or stained areas. In fact, the yellowish color is especially pronounced along these roots and often disappears where the roots end (Figure 3). The mineral composition and texture of red groundmass and yellow zones are markedly different. Secondary phosphate minerals and a higher goethite to hematite ratio characterize the mineral composition of the yellow zones. It should also be noted that Al-substitution in goethite from these areas is significantly higher than in goethite occurring in the groundmass (Figure 4).

Jan 1, 1980

By R. T. Leigh

The continued decline In the production of synthetic soda ash (sodium carbonate) due to high costs and associated environmental factors, has improved the world demand for natural soda ash. The largest resource of natural soda ash is the mineable trona deposits of Southwestern Wyoming. Wyoming trona, a lacustrine evaporite of Eocene Age, is mined by five producers which process over 90% of the United States and 20% of the worlds soda ash. Total world consumption of soda ash is forecast to grow 1% annually. Increased expansion into foreign market's is absorbing the domestic overcapacity.

Jan 1, 1989

By D. W. Park

Longwall mining is popular in underground coal production in the United States due to higher production rates and safety concerns. Because of the extreme complexity, it is necessary to plan an adequate design to achieve a safe and efficient working place. The proper sizes of yield and abutment pillars and panels can be determined by simulation using numerical modeling techniques. By means of three-dimensional modeling, stresses to be imposed on the pillars, panels, gob, and powered supports can be analyzed. In this study, an initial three-dimensional finite element model was developed and then modified into four different models. Using these models, the numerical outputs of distributed stresses on three different sizes of yield pillars, three different sizes of panels, and two different sizes of abutment pillars were compared and analyzed to determine the most adequate pillar and panel sizes. Progressive failure theory based on the Hoek and Brown failure criterion was used to determine redistribution of stresses in the yielded and failed areas in the longwall mine.

Jan 1, 1992

By C. Iglesias

Innovation in the tilemaking ceramic industry is stressing properties like powder flowability, ability to toughen green tiles, so turning technological requirements of ball clays ever stricter in terms of plasticity, dispersion in water, rheological behavior, workability in the green state, refractoriness and firing colour. Technological performance of ball clays was improved by taking as benchmark the highest quality raw materials on the market. The mineralogy, plasticity, methylene blue index and ceramic response of the Patagonian ball clays are analogous to those of European clays, but improvement is needed to approach the highest quality materials. On this basis, the Frente A, Super, Puma, and Lote 8 deposits were selected and their characteristics enhanced by additions of highly plastic and white-firing corrective clays targeted on the benchmark. Porcelain stoneware formulations, containing improved ball clay mixes, were experimented at both laboratory and industrial scale. The improved ball clays behave like the best raw materials currently used, although modest changes occur in the mechanical properties, water absorption and whiteness of the fired products.

Jan 1, 2010

By A. M. Tunstall

Blasting is commonly viewed separately from mechanical handling and crushing. This view is misleading because the degree of fragmentation achieved by blasting can have a significant effect on the efficiency of these processes and, hence, on the overall cost of the mining operation. In this paper, aspects of blasting and crushing and their interaction are examined. A case study is also presented that dramatically illustrates the influence of blast fragmentation on subsequent processing and on the financial implications involved

Jan 1, 1997

By Paul Saxton

INTRODUCTION AND SUMMARY This short paper deals with the history of the Nickel Plate Mine from 1898 to 1987, with the major focus on the time period 1984 to 1987. Operations from 1898 to 1955 are reviewed in a cursory manner with the emphasis on some interesting points in the early 20th century. A review of the major exploration work carried out in 1984 to 1987 is presented and the process of moving the project through feasibility, government permitting and construction is described. The Hedley gold camp is situated approximately 40 kilometres east-southeast of Princeton, in southern British Columbia. The area has had a long history of gold mining and between 1902 and 1955 approximately 1.5 million ounces of gold were won from several mineralized skarn orebodies. Most production came from the Nickel Plate and Hedley Mascot mines. AN EARLY TO MID 20TH CENTURY SUMMARY The Nickel Plate is one of the oldest mines in the province. The mine had operated from 1904 to 1930 and, after a period of shutdown, from 1934 to 1955. The mine was revived in 1967 for exploration and. will resume production during the first half of 1987. In the first period the Yale Mining Company and Daly Reduction Company operated for six years and Hedley Gold Mining Company for twenty-one. In the second period the mine was operated by the Kelowna Exploration Company Limited and Kelowna Mines Hedley Limited for twenty-one years. In the present period the mine has been revived by Mascot Gold Mines Limited.

Jan 1, 1987

By Ernest A. Draeger, James W. Collins

Water only cyclones, sometimes referred to as hydrocyclones, are one of the newest types of coal processing equipment. These devices have achieved wide acceptance as fine coal cleaners in the past decade. Many metallurgical coal plants employ water only cyclones to process 0.5 mm x 0 size coal. Some of these plants have as many as 40 to 50 305-mm-diam units with each unit receiving as much as 9 t/h of raw feed. The growth in the utilization of hydrocyclones is due partly to the energy shortage, partly to the general increase in over-all coal preparation, and also because of a need for a simplified fine coal (0.5 mm x 0 size) gravimetric separator. Large diameter water only cyclones are also available and in use to process feed sizes up to 32 mm in size. However, the size normally employed for cleaning 0.5 mm x 0 coal are 356 mm or 305-mm-diam for single-stage circuits. In two-stage circuits, the secondary units are normally the same diameter as the primary units or smaller, such as 203-mm-diam. By using the small diameter cyclones and treating a closely sized feed, 0.5 mm x 0 only, it has been found that the probable error or imperfection of the water only cyclones is comparable to that obtained on the same size fraction treated in a large 610-mm-diam heavy media cyclone washing 38 mm x 0. The water only cyclone can approach the efficiency of a heavy media cyclone when cleaning fine solids because it creates its own dense media by accumulating high specific gravity particles in the wide angle conical section of the cyclone. A cut-away cross sectional view of a water only cyclone is shown in Fig. 1. It is also true that when treating a wide range of sizes (38 mm x 0) in heavy media cyclones, the smaller size particles (0.5 mm x 0) separate in proportion to the split of the media through the cyclone rather than by particle density.

Jan 8, 1980