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By Madan M. Singh

A new mining project can raise questions about what effect it will have on the community after it closes. Historically, little was done by communities to plan for and accommodate the changes in the economic infrastructure when a mine project is finished either after the ore runs out or if market conditions deteriorate and make it unprofitable. Projects that were underfunded were generally unable to withstand periodic market downturns. However, data in a recent study conducted by the Seidman Research Institute leads to the conclusion that, even when a mining project is terminated, there can be (and, in the specific case studied, is) a residual beneficial economic effect in the community, which lasts for a long period of time.

Jan 1, 2010

By T. Diering

Gemcom PCBCTM is a software package which has been developed over the last 22 years for the planning and scheduling of block cave mines. This paper presents an update of the various research and development activities done to PCBC recently. It also provides an overview of the current capabilities of the software including tools for both feasibility type studies as well as tools for operating mines. PCBC is used extensively by prospective and operating block cave mines and some of the recent applications are described.

Jan 1, 2010

By C. H. Bucknam

Acid neutralization titrations were applied to the characterization of soil and overburden for the control and prediction of acid rock drainage in the coal fields of the eastern United States in the 1970?s (1). These became known as the Sobek methods as a result of the early United States Environmental Protection Agency publication and the methods have been modified (2) to be adapted to many applications in the metal mining sector (3,4,5,6,), and, as a result, there are a large number of acid neutralization potential methods being used that are referred to as Modified Sobek methods. Standardization of neutralization potential methods for metal bearing ores and related materials based on carbonate carbon, rather than titration, commenced in the 1990?s through the American Society of Methods and Materials (ASTM) Committee E01 on Analytical Chemistry for Metal Ores and Related Materials Subcommittee E01.02 on Ores, Concentrates and Related Metallurgical Materials (7). A subcommittee section, E01.02.05 on Environmental Methods, was organized to coordinate the method and material standardization efforts of ASTM and the Acid Drainage Technology Initiative Metal Mining Sector (ADTI-MMS) Prediction Committee (8), which took on the project of standardization of the acid neutralization potential acidity titration method (ANPA) to supplement the carbonate carbon method in E1915 (9) for application to samples which have metal carbonates (10), in particular, which result in overestimation of the neutralization potential using the carbonate carbon methods (11).

Jan 1, 2010

By V. A. Scovazzo

The analytical pillar design procedure employing the Wilson equation is based on the site-specific material strength of the floor, pillar, and roof rock. Stable pillars so designed will sometimes be larger than those designed using empirical methods thus providing more stability or at other times smaller than empirically designed pillars thus conserving natural resources. Presented here is a detailed procedure for the analytical design of soft rock pillars using the Wilson Equation. An example of this procedure is presented that uses data from a mine in the Owl Seam in Southern Appalachia. These Owl Seam pillars are now in use and are performing as expected. Also addressed is an assessment of the Dr. Scovazzo?s analytically designed pillars based on pillar performance data gathered by Dr. Mark in the Southern Appalachian Coal Field.

Jan 1, 2010

In September, a fleet of 363-t (400-st) Liebherr trucks became operational in Brazil and have already begun moving iron ore in Para state. Prior to the arrival of the the trucks the Brazilian fleet relied on trucks up to 218 t (240 st). With the addition of the 363 t (400 st) trucks, the fleet has since experienced the high productivity offered by Liebherr T 282 B trucks.

Jan 1, 2010

By M. Gorman

The Mineral Park Mine is an open pit copper-molybdenum mine located in northwestern Arizona, approximately 74 miles southeast of Las Vegas, Nevada. The property has been owned by the Duval Corporation, Cyprus Mining Company and Equatorial Mining of Australia. Mercator purchased Mineral Park from Equatorial in 2003. Mineral Park commissioned a 25,000 tpd copper and molybdenum concentrator in November and December of 2008. The process includes two stage milling (SAG and Two Ball Mills) fed by primary crushed ore. Metals are recovered in a copper-molybdenum flotation circuit consisting of mechanically agitated roughers and cleaners. The copper- molybdenum flotation concentrate is thickened and further processed in the molybdenum flotation circuit which separates the copper and molybdenum minerals into salable concentrates. The molybdenum circuit also uses mechanically agitated cells. This paper describes the plant and some of the highlights of the commissioning process.

Jan 1, 2010

By A. House

Newmont Mining Corporation owns and operates the Phoenix Mine near Battle Mountain, Nevada, USA. The existing milling facility has operated since 2006. Following the startup of the milling operation, and coupled with the upswing in the copper market, Newmont realized that Phoenix needed a process option to treat lowgrade transition and oxide copper ores. This meant that potentially revenue generating ore was being mined as waste. With no system in place to treat the transition and oxide copper, work began to determine the most feasible approach. After evaluating multiple options, the flow sheet was set for a run-of-mine (ROM) heap leach pad and solvent extraction/electrowinning plant (L-SX/EW). This paper will discuss the synergies and challenges of developing a copper L-SX/EW plant at the Phoenix copper-gold mill.

Jan 1, 2010

By M. Soderstrom

In a solvent extraction (SX) plant, stage efficiency calculations are used to determine mixer efficiency. With modern extractants and mixing equipment, it is generally taken for granted that stage efficiencies will be above 95%, but this is not always the case. Dependant on mixer/solution conditions, stage efficiencies can occasionally be low, therefore leading to higher reagent usage. Proper methods to identify when stage efficiency performance is below expectations, and ways to identify if it is an equipment or chemical issue are valuable tools for a plant metallurgist. With these tools and skills an on-site metallurgist can more quickly return their SX plant to proper operation. This paper will discuss methods for analyzing stage efficiency, evaluating factors that may affect stage efficiency, and evaluating the impact of stage efficiency on the overall operation.

Jan 1, 2010

By G. Deschênes

In an earlier study (Deschênes et al., 2009), gold and silver were shown to be efficiently extracted from samples taken from the Kupol Mine in Russia using lead nitrate in a cyanide leach system. In the current study, a com-parison of the technical and economic merits of a new technology called CANMET enhanced leaching process (CELP) was made with the cyanidation/acidification-volatilization-recycling (AVR) process using eight metal-lurgical variability samples, as well as a large composite sample, which was to represent the initial two years of Kupol mill feed. The composite sample leach feed assayed 33.4 g/t Au and 289 g/t Ag. The metallurgical results from the large composite sample demonstrated that CELP produced very similar gold and slightly higher silver leach extractions compared to the conventional cyanidation/AVR leach conditions at 1/2 the cyanide concentra-tion (1,000 ppm NaCN in CELP vs. 2,000 ppm for cyanidation/AVR leach conditions). It was estimated that the total cost per ton was approximately the same for the two technologies (total cost of CELP with the use of Merrill-Crowe at $46.48/t, with cyanidation/AVR at $46.13/t). However, the implementation of CELP would eliminate a capital expenditure of approximately $5 million for an AVR system based on a 2005 feasibility level cost estimate. Eight variability samples used to confirm the composite sample results showed that, on average, the gold leach extractions with CELP and the conventional leach conditions were very similar, but the average silver leach extraction was 2.1% higher for CELP. Furthermore, CELP silver leach extraction was 4.6% higher on average compared to conventional cyanidation for the four mid-grade variability samples evaluated. The decision was made to remove AVR cyanide recovery from the flowsheet and implement CELP at Kupol. The ability to use the conventional leach equipment with CELP and simplify the flowsheet was also a factor, given the remote location of the Kupol Mine.

Jan 1, 2010

By M. I. Brittan

A technique has been developed that analyzes routine mill operating data to determine the key operating parameters responsible for gold losses to tails. These parameters represent the prime operating variables having a dominant effect on gold recovery. The technique quantifies these effects for the specific plant being analyzed, providing a tool to optimize recovery and costs and so enhance the mine?s cash flow. The quantitative relationships generated will be different for each ore and plant: every case is site-specific and has to be treated on its merits. Examples are provided to illustrate the considerable metallurgical and financial benefits which can be realized from optimization. The examples are taken from case studies of mills in four major gold mining districts of the world.

Jan 1, 2010

By K. Oraee

Excessive emissions of methane from the coal seams can have a serious adverse effect on both safety and productivity of longwall coal faces. Mechanization of coal faces has increased production possibilities to the extent that normal ventilation systems may not be able to ventilate coal face areas in order to lower methane content in the air to within legal limits. Production increases may therefore be prohibited for this reason, especially in gassy seams. Methane drainage from the coal seam by means of long holes and before production starts can act as a useful remedial action. In this paper a two dimensional mathematical model has been produced. The model that is based on finite elements, simulates a methane drainage system where the resultant risk is linked to the coefficient of diffusion, coal permeability, holes pattern and the duration for which the seam is subject to drainage. It is concluded that methane drainage of this type can assist in achieving production increases in many coals seems, especially where high gas content is a virtue of the seam.

Jan 1, 2010

By N. O. Lotter

The reliability of a set of flotation results is key to minimizing project risk, either at the commissioning of a concentrator or at the point of implementing an improvement to an existing concentrator operation. High-confidence flotation testing (HCFT) was developed for this purpose and is part of the list of technologies at various scales used by Xstrata Process Support (XPS) in addressing these projects. The methodology is based on two principles: one, to ensure that the ore sample is representative and has been well-blended and subsampled; two, to perform the flotation tests in sufficient numbers of replicates with appropriate quality controls, so as to improve the reproducibility of the test data. Across ten years of research on this methodology at Xstrata Process Support, Sudbury, several improvements to the HCFT method and complementary connections between sampling and quantitative mineralogy have been developed. Two case studies are reviewed. These show the capability of this system in both optimizing an existing concentrator operation and in serving a new mine scenario. Further work to improve the efficiency of this procedure has been identified. Key words: Flotation testing, Flotation

Jan 1, 2010

By J. Urosek

Since the promulgation of the Mine Safety and Heath Administration?s (MSHA?s) Final Rule on mine seals (30 CFR § 75.335(b)), which became effective on October 20, 2008, many seal designs have been approved by MSHA and constructed by the mining industry. Since the effective date of the Final Rule, several issues on the design, construction, and/or inspection of seals have been brought to the attention of MSHA. Several such issues discussed in this paper include; the directional, design-load criteria required by MSHA for 50-psi seals, 120-psi seals, and greater-than-120-psi seals; the presence of fireclay in the surrounding strata where a mine seal is to be built; the measurement of convergence of the mine opening in which a seal has been constructed; where gob-isolation seals can be used; and the importance of periodic inspection of seals.

Jan 1, 2010

By M. Solomon

Crushers are designed and manufactured to survive the severe duty of mining environments worldwide. Under these conditions the crusher performance and availability is one of the critical factors in the mine?s production and profitability. Traditionally the development of these machines tends to be experience-based, incremental improvements in design due to challenges of different applications, duty, or manufacturing. In order to better serve the mining industry a new approach was taken to the design of primary crushers. This approach was to focus on safety and maintenance activities. The result of this effort is a new generation of gyratory crushers that can be serviced from above. Using the features of this new generation of crushers to their fullest extent crushing installations have improved safety, reduced design and construction costs, and lowered maintenance requirements. This presentation explores the benefits of two crusher installations utilizing top service crushers.

Jan 1, 2010

By J. W. Gulyas

Settling a contract for process design involves a negotiation between the design engineers and the client. Clients wish to offload as much risk as possible by seeking various guarantees about the process performance. Design engineers respond with preconditions and qualifiers, believing that the risk must remain with those who stand to benefit. This paper presents the engineers? point of view on guarantee types and precedents, performance testing, damages that may be claimed, and remedies that can be provided with particular reference to the mining industry.

Jan 1, 2010

By Hitch M.

Many mining wastes, especially those from the metal mining industry, have traditionally been treated as a matter of little or no value and in practice a cost burden. Some wastes, due to their reactivity characteristics, have emergent values that go beyond purely economic and into the environmentally beneficial realm. This paper discusses the changing paradigm of mine waste management. Such fundamental parameters such as cut off grade, and strip ratio, are positively impacted by the revaluation of waste rock material. Mine rock waste can now be seen as a commodity of value, similar to the underlying ore being mined and influences the economic performance of suitable projects. This valuable material can be used for industrial purposes including acid neutralization as well as the capture and long-term disposal of anthropogenic carbon dioxide. The Turnagain Nickel project, located in northern British Columbia serves as an example of how waste rock material can become an important matrix for carbon capture and sequestration and can benefit economically from it. By producing material that has emergent economic value as well as carbon capture and sequestration capabilities, the sequestration matrix producer is a beneficiary of new carbon credits that have a market value and is looked upon favourably by regulatory authorities and affected stakeholders.

Jan 1, 2010

Australia is a hub for mining technology development. The paper describes many of the key players involved in mining research in this country along with some of the interesting research outputs to emerge over the past decade.

Jan 1, 2010

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 Wayne Green

The Regional Municipality of York, located north of the City of Toronto in Ontario, Canada, has experienced unprecedented growth during the past decade, with new home construction averaging 15,000 units per year. This rate of growth is planned to continue well into the future with a projected growth of more than 500,000 new residents by 2031, combined with a tar-get of more than 300,000 new jobs to provide a sustainable economic base for the region. It should be noted that York region has been designated as one of the key growth centers by the province of Ontario, aimed in part to meet the housing and employment needs of Canada?s growing population. York Region is a mix of urban and rural areas and is one of the most desirable areas to live in Southern Ontario. York region offers an attractive lifestyle, with its nine municipalities and the amenities created by the many rivers, streams and protected greenbelt areas that encompass more than 69 per cent of the region?s area.

Jan 1, 2010

By ?. ?ivkovic

The silicate slag and copper matte that are the byproducts of smelting copper in a reverberatory furnace contain SiO2, FeO, Fe3O4, CaO and Al2O3, and Cu, Fe and S, respectively. These components influence the oxide (Cuox), sulfide (Cusul) and total (Cutotal) copper content lost in the waste slag. This paper uses multiple linear regression analysis (MLRA) to determine the degree of influence. The results of calculations obtained using MLRA were compared to actual measured results and found to have a large degree of correspondence, with the coefficient of determination R2 = 0.975. These results indicate that slag composition and copper content in the matte influence the copper losses in the waste slag with a probability of above 97%. It was determined that, of the total copper content of the slag, 74% is in sulfide and 26% in oxide form, and that this ratio is not dependent on the slag or matte composition.

Jan 1, 2010