Search Documents

By Armstrong

This is a world of change and has been from the beginning. There are constant efforts on the part of natural forces to wear down the high spots and fill in the low spots. Wind and water over eons of time tunnel through obstacles and build windways and waterways to make movement of air and water easier and more efficient. It is a natural, never ending, ever changing continuing effort. Man in his struggle to survive, and to progress, has had to adapt the terrain of the earth to fit his needs the best he could. First, he used natural caves to protect him from the elements; then he learned how to build earth and rock-moving tools from antlers, bone, rocks, and sticks and adapted his cave to increase his security and provide better protection from heat and cold and from his predatory enemies. As his numbers increased, so did the necessity of further adapting his environment to accommodate his needs. Water was usually not available when and where needed, especially in the desert areas where civilization developed, and long tunnels were drilled to intercept ground waters and lead them to underground caves carved out of soft limestone. Most of the tunnels of early man were to bring water from where it was to where man needed it. Then, as now, as man increased his chances for physical survival, he turned to the quality of life -- and this reflected in the concern for life after death. This lead to the elaborate shafts and tunnels for the protection and prservation of the more affluent noblemen and pharaohs of the early Egyptian civilization. Man used the underground for the stable temperature and for protection and safety.

Jan 1, 1974

By A. G. Wylie

The dimensions and shape of both airborne and bulk amphibole-asbestos fibers are different from those of cleavage fragments of the amphiboles. These differences are related to the mineralogical properties unique to the habit of asbestos. These properties include the fibrillar structure, small fibrill widths and distinctive crystallographic faces of fibrills. Criteria for distinguishing amphibole cleavage fragments from amphibole-asbestos include mineralogical proper-ties observable in bulk samples and the dimensions of particles collected on air filters.

Jan 1, 1988

By T. R. Ellis

The author is the leader of the Extractive Industries Task Force of the International Valuation Standards Committee. The Task Force has developed an Extractive Industries section for inclusion in the International Valuation Standards (IVS). The Extractive Industries Guidance Note provides comprehensive standards for valuation of all minerals and petroleum industry property types for all valuation/appraisal purposes. The document is scheduled for release as an exposure draft for public comment by December 2003, then it will be finalized for publication in the IVS in mid-2004. This paper discusses the content and philosophy of the Extractive Industries Guidance Note within the context of the framework of the IVS. It also discusses the international implications and implementation of this IVS addition.

Jan 1, 2004

By Gary A. Nowlan

The Casa Grande West-Santa Cruz porphyry-¬copper deposit is in the Basin and Range physiographic province west of Casa Grande, Arizona (Fig. 1). The Casa Grande West portion of the deposit is controlled by Casa Grande Copper Company and the Santa Cruz portion by ASARCO. The deposit contains at least 350,000,000 metric tons of rock with greater than 1 percent Cu. The deposit is covered by at least 300 m of sediment, with no visible expression of the deposit at the land surface. The deposit is in an area of prime agricultural land that depends heavily upon well irrigation because of a hot and arid climate. Because of the deep sedimentary cover, the chance is extremely remote that the geochemistry of soil or stream sediment would reflect the deposit even if the land surface were not disturbed by many years of farming. Irrigation wells of the area generally bottom in the sedimentary cover. The purpose of the study is to see if the Casa Grande West-Santa Cruz deposit is geochemically reflected in ground waters over and near the deposit.

Jan 1, 1981

Impala Platinum?s No.16 Shaft mine is currently under construction and is expected to reach full production of 256 500 tons per month by 2014. Mining will start at 1 260 m below surface with a maximum mining depth of 1 535 m where virgin rock temperatures of 56.6°C will be experienced. As a result of depth, high virgin rock temperature and narrow reef mining, an expected total of 31.5 MW[R] of air cooling capacity will be required to achieve acceptable underground conditions. This will be achieved by cooling mine intake air in a single dedicated air cooling installation located on surface. The compact installation includes air cooling spray chamber, refrigeration machines, condenser cooling towers, evaporator and condenser water reticulation as well as all electrical and control systems. Construction and commissioning of the first phase of this air cooling installation has recently been completed on a turn-key contract basis.

Jan 1, 2009

By R. D. Williams

In spite of the increasingly polarized and politicized view of climate science and climate change in the United States, many of the principles behind the ?theory? of Anthropogenic Global Warming (AGW) or Global Climate Change (GCC) are in fact firmly established both in fundamental physics and detailed observations and are widely accepted elsewhere. The discovery of the earth?s ?greenhouse effect? dates back nearly 200 years to the work of French mathematician and physicist Joseph Fourier in 1824 and 1827. In 1872, John Tyndall an English physicist and mountaineer, described the capacity of various gasses to absorb radiant heat. He identified water vapor and carbon dioxide as the principal ?greenhouse? gasses. The work of Fourier and Tyndall was the foundation for the theory that increasing carbon dioxide (CO2) in the atmosphere might be responsible for an increase in global temperatures developed by the brilliant Swedish chemist Svante August Arrhenius in 1896. This was backed up by the additional work of Gilbert Callendar in the 1930s, and Gilbert Plass, Hans Suess and Roger Revelle in the 1950s. There is little scientific dispute about the physics by which this occurs: carbon dioxide in the atmosphere absorbs long wave radiation that would otherwise escape into space, thus warming the lower atmosphere and respective temperatures worldwide. The Intergovernmental Panel on Climate Change (IPCC), approximately 2500 climate scientists from around the world, has concluded that increases in carbon dioxide resulting principally from the burning of fossil fuels are responsible for most of the continuing increases in global temperatures (IPCC, 2007). NASA?s Goddard Institute for Space Studies (GISS) states; ?The ten warmest years all occur within the 12-year period 1997-2008? (GISS, 2009). 2009 was the second warmest year on record and 2010 was tied with 2005 for the warmest year on record (GISS, 2010, 2011). The science is in fact settled; the earth has not cooled since 1998 as some have claimed. It continues to warm as evidenced by not only surface temperature records but also ocean temperature records as well as changes in physical and biological systems (IPCC, 2007).

Feb 27, 2013

By Claude E. Wykes

Deep Well turbine pumps receive constantly increasing application to the problem of mining water and other fluids from great depths. Many installations of medium settings are presently operating successfully and it is felt that mach greater depths are immediately within reach. Settings and lifts in excess of 2000 feet: are not at all out of reason with present knowledge experience, and materiels; however, conditions of individual applications will govern in each case and dictate methods and possibilities to the designer. Design and operating problems of deep set -turbine pumps ire discussed together with a description of various types of equipment falling within this category. Although the deep well turbine pump has been produced In the vertical turbine pump industry for many years, the connotation of the word "deep" still remains questionable. Among the manufacturers of this type of machinery, answers to the question implying the practical limitation of setting for a deep well pump will vary to an extreme. Most pump designers are in accord that this type of equipment has not yet been exploited to its fullest degree; however, the subject is admittedly fraught with unsolved problems and un¬tried solutions so that such a discussion must necessarily derive from personal opinion and, belief., even though based on substantial experience and background. For this reason, it will be stipulated that the present writing will deal with what may be termed euphemistically ?a highly controversial subject.? During the nineteenth century, a paper was published under proper authority proving beyond question that the human body could not withstand speeds exceeding 20 miles per hour. As a limitation, this looks ' pretty ridiculous to us today. At the beginning of the twentieth century, there was not a single machine in operation that could be described as mullti-stage deep well centrifugal pump. As a matter of fact, very few centrifugal pumps of any type wire operating against heads in excess of 50 feet, since such applications were considered impractical. In the

Jan 1, 1960

By G. E. Erdman

The total attitude of the industrial minerals producing company is a most important factor in how they regard quality control, technical support for their customers, and procedures used in mining their minerals products. This philosophy of the producing organization directs their action along certain courses. For instance, one producer might see itself as a mining company with its major goal mining efficiency to make it exceedingly price competitive in the market place. Another producer might see itself as a wide spectrum multi-mineral producer that furnishes a reputation for a complete line of products. Another producer might see itself as a specialist in one specific industrial mineral and bet its whole bankroll on providing the very best of quality with the goal of becoming the largest producer of the mineral commodity. Each perception can have a different impact upon the producer's operations and its regard for quality control. Minerals Being Produced The specific markets being served will have their own influence on how mineral product quality is regarded. Ceramic raw materials, for instance, have a very low tolerance for iron which is the cause of low fired color. Thus, industrial minerals for use in glass and ceramic markets must be won from deposits with a very low iron content. A high iron silica sand might be sold to a manufacturer of good old beer bottles. That is a solution to one particular quality facet, but eliminates selling to a significant market in clear glass, porcelain enamel, ceramics whiteware bodies and hobby glazes. Thus, there is a need for sound research in the industries expected to be served before the product is brought to market.

Jan 1, 1987

By D. Kumar, R. J. Sweigard, J. Silva

The Forestry Reclamation Approach (FRA) recommends that the upper 1.22 m (4 ft) of spoil material on reclaimed surfaces should be left as uncompacted as possible to facilitate efficient tree root growth. However, the main concerns about applying the FRA to steep slopes is that the upper 1.22 m (4 ft) of loose spoil material could cause instability. Successful application of the FRA on the flat and rolling surfaces precipitated this investigation. Details of a field investigation conducted at a steep-slope mine site are available in an earlier publication (Kumar and Sweigard, 2011). A total of 70 survey monuments were driven into the slope in a regular pattern to monitor any type of slope movement. Quarterly surveying of the monuments were done to quantify slope movement, either horizontally or vertically. The methodology developed in this research for field slope movement monitoring was validated using computer model results. Analytical models based on the limit equilibrium method (LEM) and numerical models based on the finite element method (FEM) were developed for slope stability analysis. The LEM analysis was done using the Geo-Slope/W program following the simplified Bishop method. However, numerical models were developed using the PLAXIS computer program following the Mohr’s Coulomb failure criterion and strength reduction technique. The slope stability analysis was performed for two different scenarios: first with the top 1.22 m (4 ft) of loose graded spoil material and second without top loose graded spoil material. Finally, the field investigation results were compared with stability analysis results. Both of these approaches showed that application of the FRA on steep slopes is not causing any significant instability problems, due to 1.22 m (4 ft) loose graded spoil that would not exist otherwise for overly steepened slopes.

Jan 1, 2013

By Jan K. Wolski

Detection of the air recirculation branches within a large ventilation network may be difficult, therefore a PC computer routine has been developed to perform this task in an efficient and reliable manner. This paper describes the method illustrated using a network with complex multi-recirculation circuits. The fact that only the air flow directions and not the flow rates are used in calculations is of some interest. The air recirculation during a real mine fire is demonstrated using the PCVENT program, whose version 4.0 includes current information about any recirculation branches during network calculations or during a fire simulation. This paper also discusses some transient problems related to air recirculation, and gives examples.

Jan 1, 1993

The impact of smoothing on the definition of ore and waste boundaries using linear estimation and conditional simulation methods is discussed. The nature of transfer functions is examined including their ability to incorporate categorical data (e.g. a dominant lithology code). An Ore Block Optimization (OBO) transfer function is presented that provides a clear guide for the mining geologist. Advantages are seen in defining stockpile cut-off grades and meeting production targets such as maximizing head grade, maximizing ore tonnes or minimizing ore loss or dilution. Each of these scenarios impacts on mine profitability and grade control.

Jan 1, 1999

By William X. Chavez

The Mantos Blancos copper-silver district is located in northern Chile about 45 kilometers northeast of Antofagasta, as shown in Figure 1. Disseminated and veinlet copper and copper-iron sulfides containing economically significant silver values are hosted by andesitic to rhyolitic volcanic rocks of probable Jurassic age (Chavez, 1983). Field, mineralogical, textural and lithochemical evidence show that three major alteration types may be recognized within the district: (1) district-wide sodium metasomatism, manifested as albitization of feldspars and development of albite veinlets and pore-fillings, (2) local to widespread, incipient to intense addition (chloritization) or removal (bleaching) of magnesium and iron and (3) local to widespread, moderate to intense hematitization, usually spatially associated with bornite-digenite-covellite (as specularite) or digenite-covellite-chalcocite (as red hematite staining with or without specularite) mineralization. Carbonatization, occurring as veins, veinlets, vesicle fillings and irregular patches of calcite, varies in magnitude of development but is widespread. Sericitization of feldspars and groundmass is only locally intense yet is generally present as incipient alteration throughout the district. The district-wide albitization of the Mantos Blancos volcanic sequence has altered what were originally more potassic and calcic, less sodic, rocks to what are now more properly referred to as keratophyres (Battey, 1955; Gilluly, 1935, Hughes, 1975). The petrographic and lithochemical characteristics of the three major alteration types noted above are summarized below.

Jan 1, 1984

By Paul J. Ehret

With the passage of the Surface Mining Control and Reclamation Act (SMCRA), and the implementation of state permanent programs, underground coal mining operations are for the first time subject to government regulations regarding subsidence. These regulations now and in the future will directly affect the manner in which mining companies mine their coal. Since the promulgation of the original final regulations by OSM, numerous changes in those regulations have been made and many additional changes are pending in the near future. This paper will discuss state and federal approaches to regulating underground coal mines and examine issues surrounding future subsidence regulations.

Jan 1, 1986

By Quanjun Liu, Rongping Lin, Rongdong Deng

Arsenic contamination significantly affects the quality of copper concentrates, presenting challenges during smelting processes. Considering that covellite and enargite have similar surface properties, they are difficult to separate by flotation, resulting in copper concentrates with excessive levels of arsenic. To address this issue, this study systematically investigated the flotation separation of covellite and enargite in microflotation and bench-scale flotation tests using calcium lignosulfonate as a depressant, with the results indicating that calcium lignosulfonate can be used to separate covellite and enargite because it enables the separation of arsenic-bearing copper minerals into high- and low-arsenic (As 0.57%) copper concentrates. According to contact angle and adsorption tests, scanning electron microscopy–energy dispersive spectroscopy, and X-ray photoelectron spectroscopy, the differential adsorption of calcium lignosulfonate onto covellite and enargite is the primary reason for their distinct flotation behaviors in the presence of calcium lignosulfonate. The selective depressive effect of calcium lignosulfonate provides a novel approach for improving the flotation separation of arsenic-bearing minerals from copper sulfide minerals.

Feb 28, 2024

By Roland Trunk, Marcel Imbach, Yves Boissonnas, Jan Vesely

"INTRODUCTION The expansion of the Suez Canal, which runs between the Mediterranean and Red Sea, is at the top of Egypt’s economic agenda. The £8 billion development plan includes a new channel alongside the existing one which will double the number of ships able to pass each day and several tunnels to connect the Sinai peninsula to the main part of Egypt. The Egyptian government ordered three new tunnels under the Suez Canal in the area of Port Said as part of the Canal Region Development Plan. The three tunnels will contribute to the North Sinai expansion, helping to create a vast industrial zone and completing the coastal road extension from Rafah to Nuewiba. Two of these three tunnels will be allocated for roads and the third for railway traffic. A further part of the Suez Canal development mega project are an additional six tunnels in the area of Ismailia and Suez. The focus of this paper is on the two road tunnels in Port Said and will give an overview of the project and the challenges encountered regarding the technical complexity and tight time schedule both in its design and execution. PROJECT OVERVIEW The tunnels will be built in the area of Port Said (see Figure 1) which is the most northern part of the Suez Canal.The road alignment connects the Port Fuad Road in the east bank of the Suez Canal to the Port Said-Ismailia highway in the west bank with a dual carriageway section. Each of the carriageways has two lanes. The bored diameter of the 2.8 km long road tunnels is 13.050 m and will be driven with two Mix-Shield TBMs. The distance between the two tunnel axes is planned with 42.5 m (discussion about a reduction are ongoing). The width of the Suez Canal is around 340 m at upper level and around 170 m at the bottom. During the TBM drive, three main geological layers are expected. Below a depth of around 40 m in a very soft clay layer, a dense to silty sand layer is predicted. Within the sand layer another silty hard clay is expected in different depths with variable thickness. After finishing the excavation of the road tunnels, the same TBM will be used for the railway tunnel. The lowest points of the road tunnels will be located 59 m below the surface (tunnel invert to surface) and only 18 m of ground cover exists between the tunnel crown and the Suez Canal invert. Minimum ground cover over the tunnel crown is approximately nine meters at the tunnel portals."

Jan 1, 2016

By JA Vallejos

High stress underground mining poses a significant challenge to rock mechanics and rock engineering. To overcome theses challenges significative improvements in solutions and best practices of the design and operation of mines under high stress have been developed and implemented. This paper presents certain topics related to the management of high stress for sustainable underground mining. The topics include; the effect of preconditioning techniques (destress blasting and hydraulic fracturing) in the seismic rock mass response to underground mining and the dynamic behaviour of rock support systems. The opportunities associated with research in rock mechanics and practical rock engineering are discussed.

Apr 26, 2022

By Paul Kents

The Canadian Javelin Limited Cerro Colorado copper-porphyry deposit in Panama, possibly the largest known copper-porphyry, contains between 1350 and 450 meter elevations, drill proven and probable ore in excess of 3.0 billion tons averaging 0.65% of copper equivalent. The deposit is located in the Central Cordillera Range, straddling the Continental Divide at 1500 meter elevation. Local topography is very steep. Accessibility is difficult, all logistics made by helicopter, and only recently a 52 km. road from the Pan-American highway was completed into the area. The deposit was discovered in 1969, and since then 75 shallow exploratory holes and 98 deep holes, the deepest 1340 meters, totalling 45,000 meters have been drilled. Deep holes were drilled at the corners of a regular rectangular 150 meter grid.

Jan 1, 1975

By Don Stainbrook

Over a period of many years a highly automated computerized system of ore control has been developed at the Newmont Gold Company, (NGC). It is the purpose of this paper to review the development of this system, describe the setting in which it functions and to mention some of the future developments and enhancements. Discussion of the evolution of the system in a historical perspective helps to understand its present status and illuminate some thinking about future directions of development.

Jan 1, 1989

By John G. Whellock

Over the last decade new constraints have emerged in the metallurgical industry which challenge the very basis of design and construction of smelters and refineries. The hackneyed designs of the past will not now serve the revised objectives of: - minimal cost of ownership - improved productivity - reduced energy consumption - greater flexibility in feed or product - minimized recycle loops and by-products - more stringent environmental control The impact of these constraints has been channeled constructively into process intensification - exemplified at the large scale by the introduction of flash smelting technology and at the smaller scale by the application of rotary process vessels and converters for augmented heat and mass transfer. The design of successful process plants depends on the understanding of the unit operations and their interactions which is the discipline of systems engineering. With the advent of increased process intensification the importance of a systems approach to process design and implementation becomes paramount. This paper describes the systems approach with specific reference to medium scale projects in the primary and secondary metallurgical industry.

Jan 1, 1985

By D. Hulse

Mineral resource classification is described in both the SME and CIM Standards for Mineral Resource Reporting. The CIM Standard states “… sampling … is sufficient to assume geological and grade or quality continuity between points of observation”, thus is a function of continuity and sample spacing. Continuity can be measured by use of a variogram model, but average sample spacing in three dimensions is more difficult to measure. The declustering algorithms provided with Geostatistics software, are commonly used to weight data for statistical analysis due to the sometimes-irregular spacing between drill holes during exploration. The weights are lower when data is closer, reflecting shared influence between samples, and higher for isolated samples reflecting independence. This paper will discuss the potential to use estimates of the declustering weight as an inverse relative measure for average sample spacing to gauge the confidence of the estimate independent of the single nearest sample. PROBLEM The classification of mineral resources and reserves has long been a combination of science, past experience of the estimator, judgment, and feeling. All of the definitions as presented in the standards of the various countries that participate in CRIRSCO are similar and deal with “sample points sufficiently closely spaced to support confidence in the continuity of …” This has been interpreted as the distance between the block estimated and the nearest sample (or samples). Geostatistics gave us the calculation of the estimation variance of the block, an implicit part of the calculation of weights in Kriging, to account for the confidence in the estimate. More recently, “Kriging Efficiency” has been used, however it is still dependent on the estimation error and responds in a similar fashion to the distance to the closest sample. It is also sensitive to the variogram nugget. Many of these methods result in very low distance/high confidence measures for blocks adjacent to a sample point with confidence decreasing (sometimes rapidly) as the distance to one nearest sample increases. This results in the “spotted dog” phenomenon where individual samples are surrounded by a higher classification near each sample decaying into pattern of decreasing confidence halos. In addition to the visual image of the spots, this raises the more practical problem of mine design when the classification changes between measured, indicated and inferred. This has led to ad hoc methods to classify material within the mining block so all of the stope receives that classification. These manual methods re both labor intensive and subjective. A popular technique is a multiple search method, where the estimator defines a minimum of number of samples from a minimum number of holes within a nested set of search distance that are used to classify estimates. These specified set of increasing distances are usually proportional to the variogram range. While this is generally a good technique and overcomes the spottiness of the closest sample or kriging error, it has certain issues including:

Jan 1, 2019