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By Ronald G. Schmidt

AND SOME RIN UP HILL AND DOWN DALE, KNAPPING THE CHUCKY STANES TO PIECES WI' HAMMERS, LIKE SAE MANY ROAD MAKERS RUN DAFT. THEY SAY IT IS TO SEE HOW THE WARLD WAS MADE. Sir Walter Scott St. Ronan's Well - 1824 In the minds of many, geologic exploration has advanced little since the early nineteenth century. In truth, despite the development and refinement of new and potentially valuable technological tools, the approach or philosophy of the explorationist has received meager attention in professional literature. In many areas, the explorationist relies upon experience, subjective judgement and general intangible inspiration, often traveling together under the misleading pseudonym of "art," in achieving both an exploration plan and in making the myriad day to day decisions necessary to the execution of that plan. Without a solid, objective basis for decisions, exploration under this concept is little more than guesswork largely by intuition, and it is small wonder that many exploration programs flounder in a sea of over-expenditure inefficiency or fail to fulfill their expected goals within the funding which has been provided. From a rational management point of view, such a state of affairs is frustrating and inconsistent with the application of the same scientific principles which are presumed to be the basis for the exploration methods which are used. This somewhat presumptuous point of view cannot be extended as a general condemnation of the many exploration programs which are both technically and economically successful. On the other hand, the

Jan 1, 1968

By Felicia F. Peng

The plant data were collected from three streams around a dense medium drum for coarse coal cleaning operated at various volumetric ratio of medium-to-feed. The effect of the volumetric ratio of medium-to-feed (MF) and particle sizes on the performance criteria, g50 and Ep, of the dense medium drum. These measured data were adjusted and calculated for the yields and balanced relative density distributions by mass balanced method based on the statistic principle. These balanced data were then used to formulate the mathematical models of the separation distribution curves for the various feed size intervals. The correlation equations for the g50 and Ep as the function of inverse of the feed size, and MF and total throughput were established. A numerical algorithm utilizing the Secant method, based on the root searching principle, was developed for yield optimization and simulation of dense medium drum separation to improve the separation efficiency and hence the product yield. The relationships between the direct ash content and relative density of the particles in feed and the products were established and incorporated into the numerical algorithm for predicting the product quality.

Jan 1, 1996

By Ronald J. Roman

A mathematical model was developed for the grinding and flotation section of Union Carbide's Bishop mill and this model was used to indicate how variations in grind, retention time, and calcite and fluorite content effects the mill capacity, tungsten units produced, and the grade and recovery of the scheelite concentrate. A model such as this is a starting point in determining the economic optimum running condition for a mining and milling operation and an example of this is given.

Jan 1, 1969

By Brian J. Gorva

The key objective of forming a cartel is to increase profits to members of the cartel by taking the following action: a) control output; and b) control price. However, while attempting to obtain monopoly profits the cartel members have to contend with costs associated with cartelization and such costs include the following: political costs; the cost of coordinating output and price; organizational costs (such as cheating); and administrative costs (such as the cost of attending cartel meetings). The objective of commodity exchanges is to provide an open, free market where buyers and sellers may openly complete transactions and pricing information can be immediately disseminated. These transactions include the following: a) to provide facilities for "hedging", or transferring price risk from buyers and sellers of physical commodities to "speculators" through the medium of buying and selling futures contracts, and b) taking physical delivery of metal on due dates.

Jan 1, 1983

By James M. Barker

The occurrence of borates and zeolites at Mesa del Alamo is well documented by McAnulty and Hoffer (1) and Lefond and Barker (2). Further investigation indicates the presence of priceite and meyerhofferite in addition to the howlite (1) and colemanite (2). Analcime occurs in addition to the clinoptilolite and phillipsite (2). The Mesa del Alamo area is about 200 !a south of Tucson, Arizona, and 13 km southeast of Magdalena, Sonora, Mexico, just south of the unpaved road to Cucurpe (Figure 1). The geology and mineralogy of northcentral Sonora is known only on a regional basis except for small areas mapped in detail during copper exploration. The study area is within the Basin and Range province of North America from which borates and zeolites are now produced in California. The borates and zeolites at Mesa del Alamo occur in geological environments similar to those of the Mojave and Death Valley regions of California (3, 4). Thus, a detailed exploration pro- gram in the Magdalena area could result in the discovery of economic borate and/or zeolite deposits.

Jan 1, 1979

By P. D. Rao

Chemical and physical properties of typical low-rank coal (LRC) ash are significantly different than bituminous coal ash. With the exception of extraneous ash, which is incorporated during mining or is due to ash partings within or between coal seams, LRC ash consists primarily of inherent ash that is bonded into the coal's organic matrix or finely disseminated mineral matter. This paper reviews the nature of LRC ash, both inherent and extraneous, and how this impacts the prospects of washing and utilizing LRCs. A literature review, as well as washability data, proximate and ultimate analyses and ash analysis of 25 Alaskan LRC seams are used as a basis for this discussion. The authors' recent research into the nature and distribution of phosphorous in an Alaskan LRC is also discussed

Jan 1, 1997

By J. -B. C. Varnier, J. A. Cremeens, D. D. Overton

"Slope failures that occurred in 2008 and 2009 at the Pikeview Quarry in El Paso County in Colorado in the United States were investigated using three-dimensional discrete element modeling methods. Large-scale block sliding failures occurred along weak bedding planes that dip steeply into an excavation located at the toe of the slope. Several mining sequences at the toe of the slope were simulated to evaluate the effects of various degrees of extraction and backfill on slope stability. Slope stability back-analysis was conducted using prefailure and post-failure conditions to determine the joint shear strength properties. Laboratory testing was also conducted to determine intact rock properties. Three-dimensional discrete element analysis was uniquely applicable to this evaluation because it allowed representation of shear stress of the basal sliding surface and afforded evaluation of several scenarios of extraction and backfill at the toe of the slope. IntroductionThe Pikeview Quarry is an aggregate quarry located approximately 8 km (5 miles) northwest of Colorado Springs in El Paso County, CO, USA. The quarry has been operated by several owners since the early 1900s. According to the U.S. Mine Safety and Health Administration (MSHA, 1986), the quarry has been a major source of construction aggregate for the Colorado Springs area for many years. In the 1950s, the site was mined by Peter Kiewit and Sons to provide limestone for the construction of the nearby Air Force Academy.A large-scale slope failure occurred on Dec. 2, 2008, which stopped mining activity at the Pikeview Quarry. A second, related slope failure occurred on Sept. 13, 2009. The second slope failure was located immediately adjacent to the initial December 2008 failure.The objective of this paper is to discuss the three-dimensional slope stability evaluation. The causal relationships of slope instability are not within the scope of this publication. However, omitting the precursors to slope failure would limit understanding of the nature of the slope stability evaluation. The regional and local geology and the history of slope instability at the Pikeview Quarry aid in understanding these precursors. Two main failure mechanisms were hypothesized during the failure investigation to explain the triggering of the 2008 and 2009 large slope failures at the Pikeview Quarry, and both of these mechanisms were given equal credence in the present study. Quarry excavation and backfilling was a key factor in the slope instability for both failure mechanisms. The excavation was backfilled in stages in an effort to provide slope support. The objective of the three-dimensional model was to evaluate the effects of extraction and backfill at the toe of the slope with respect to slope stability."

Jan 3, 2018

By J. Zhai, Z. Yin

"The electrokinetic and flotation behaviors of ilmenite using lead ions as the activator and sodium oleate as the collector were studied. The results of microflotation show that the flotability of ilmenite can be improved by lead ions obviously. The isoelectric point of ilmenite increases from 5.32 to 7.7 after the addition of lead ions because of the adsorption of Pb2+ and Pb(OH)+. The results of zeta potential measurements and the collector adsorption density calculation show that the adsorption of sodium oleate on the ilmenite surface via chemisorptions in addition to electrostatic interactions. Besides, the adsorption density calculation results show that as the addition of lead ions as the activator, the adsorption amounts of collector are greater than those without activation which is in aggrement with the flotation behaviors. INTRODUCTION Ilmenite, as an oxide mineral of formula FeTiO3, is usually used as the main resource of the extraction of titanium (Bulatovic and Wyslouzil, 1999). There are many researches showing that the conventional methods, such as gravity separation, magnetic separation and flotation, do not work efficiently as expected (Mehdilo et al., 2015; Zhu et al., 2011). Nowadays, to produce ilmenite concentration feasibly and efficiently, these separation methods above are combined for a reason that the raw ilmenite ores are characteristic of poor, fine and complicated. Moreover, surface modification, such as surface dissolution method, microwave irradiation and oxidation roasting, is applied to improve the flotability of ilmenite currently (Welham and Llewellyn, 1998; Zhang and Ostrovski, 2002). Generally, fatty acid salts are used as the collector for the flotation of oxide minerals and sodium oleate is usually used as the collector for the flotation of imenite ores (Fuerstenau and Pradip, 2005). The mechanism, such as individual ion electrostatic adsorption, chemical adsorption, ion–molecule dimeric complex adsorption, and the coadsorption of ion and molecule, have not been discussed systematically using sodium oleate as the collector in the flotation of ilmenite (Somasundaran, 1983). Under the activation circumstance using the lead ion as the activator and sodium oleate as the collector, the interaction mechanism seems to be still unclear. In the present study, the interaction mechanism between ilmenite and sodium oleate using lead ion as the activator are studied by microflotation, zeta potential measurements and adsorption density calculation. EXPERIMENTAL Materials and reagents Pure ilmenite minerals were obtained from Panzhihua, Sichuan province, China. The minerals were ground in a porcelain mill with an agate ball. Following that, the prosucts were sieved, and the samples of -0.074+0.038 mm size fraction were used for the microflotation experiments. The results of XRF show that the content of titanium element is 30.58%, showing that the purity of ilmenite is above 90%. On the basis of the results of XRF, it is determined that the purity of ilmenite is very high and meets the needs of microflotation"

Jan 1, 2017

By J. D. Miller

Contact time during bubble/particle collision is calculated by taking into considera¬tion the effect of bubble and particle motion, buoyant force, bubble size, and particle size and specific gravity density for different cases of collision. From this motion analysis approach for the prediction of contact times and from bubble attachment-time measurements,, fundamental aspects of flotation such as flotability, kinetics, and separation can be explained and are discussed with respect to the effects of bubble/particle motion, bubble size, particle size, and attachment time.

Jan 1, 1987

By E. C. Winegartner

In producing and selling coal, the coal company is faced with many different parameters by which the quality of its product is evaluated. One type, which we choose to call the economic parameters, includes moisture, ash, sulfur, and Btu's. These are reasonably well understood by both the coal supplier and the customer, and the dollar values can be placed on them. This is the group of parameters of primary interest to most purchasing agents buying coal. A second group of parameters governs how the coal will behave in the boiler itself and is of primary concern to the engineers designing the boiler and to the men who must operate and maintain it. Since we have not yet learned to put dollar values on these parameters, they generally show up in coal contracts simply as cutoff points, the purchaser simply saying that he will not accept coal outside of certain limits.

Jan 1, 1975

By Gary Peach, Peter Mason

Planning and estimating progress rates and costs for tunnelling is always best done based on experience and historic precedent. Much precedent is available but the use of data monitoring, data mining and other retrieval techniques on modern TBM machines can enable this to be further expanded and refined. Advance rates can be related much more closely to rock types as can associated rock bolt and mesh/ shotcrete requirements. This in turn can lead to a further refinement in best likely combinations of equipment, such as shotcrete jumbos, better selected for the anticipated conditions, rather than the potential advance rates of the machine. Efficient and timely construction of the tunnel will also be linked to times needed for finishing work, such as contact and void grouting and to how this can be initiated while the TBM is still in operation, in order to save overall construction time. Indeed, this in turn may affect the most preferable layout and construction details of the permanent tunnel. Considerable experience has been gained in the use of two large diameter TBM tunnel drives through the Himalayas at the Neelum-Jhelum hydropower project in Pakistan. All the above aspects will be discussed in the paper based on the considerable experience and data which came from that operation, including appropriate measures in highly stressed areas potentially subject to rock burst.

Jun 13, 2021

By Michael Li, Kathryn Rogers, Arie Moerman, Mike Cooper

The Brunswick Mine, a Division of Noranda Inc., produces zinc, lead, copper, and bulk lead-zinc concentrates through underground mining of a large massive sulphide deposit. The mining method employed is longhole open stoping with delayed backfilling. In 1996 Brunswick began a review of its mining methods and backfilling operations. In 1997 the decision was made to convert the backfill system from cemented and uncemented rockfill to paste backfill prepared from mill tailings. This paper will describe the features of the backfill preparation and distribution systems, review the handling of technical issues, and discuss experiences since plant commissioning.

Jan 1, 2001

By Timothy O’Rourke, Karrie Buxton, Chris Lynagh, Daniel Dobbels, Frederick Vincent

The Doan Valley Storage Tunnel Project in Cleveland Ohio was constructed to control Combined Sewer Overflows (CSOs). It is a complex system of three tunnels ranging from 8.5 to 18 feet in diameter with a total length of about 2.3 miles that was put into operation in mid-2021. The project lies within and below the cultural, educational, and medical hub of Cleveland, which presented unique design and construction challenges. This paper provides a case history of the design and construction, with particular attention given to lessons learned in devising a large tunnel system that can carry both dry and wet weather flows constructed in rock with limited cover, within a flood plain area and vibrant urban center

Dec 1, 2022

By W. Joseph Schlitt

Aqueous SO2 (sulfurous acid) is an interesting chemical compound. It functions as a reagent in various hydrometallurgical systems, but also represents an undesirable constituent in pyro- and hydrometallurgical effluent solutions. When present in such streams, SO2 can be oxidized to the more stable sulfate form to avoid exsolution of SO2 as a source of fugitive emissions and to simplify standard water treatment plant operation. This study provides information on the stoichiometry, kinetics and mechanism of SO2 oxidation using oxygen and an iron salt catalyst with solutions containing 0.05 to 20.0 g/l S02. Other test variables include iron salt concentration, oxygen pressure, temperature, degree of agitation and pH.

Jan 1, 1982

By Pramod C. Thakur

During the past ten years, the US coal industry has experimented with various ways to extract methane from coal seams. Drilling long horizontal boreholes in solid coal from mine workings and vertical gob degas boreholes are becoming standard techniques for methane recovery from coal seams. Prime motivations for such work have always been safety and productivity in mines, but the commercial value of gas so produced is encouraging utilization. The paper reviews various ways to produce methane from coal seams and discusses some utilization projects extant in the industry.

Jan 1, 1984

By C. L. Lin

A PC image-based on-line coarse particle size analyzer has been developed to measure particle size distributions under plant situations where overlapped particles are being transported on a moving belt conveyor. Although previous testing had shown satisfactory performance of this image-based system for separated particle size measurements (the non-overlapped case), it was necessary to modify original algorithms in order to solve the overlap problem and make the system suitable for plant operations. On-site testing has been conducted at a large copper concentrator in the southwestern U.S. for further investigation of the overlap problem.

Jan 1, 1995

By R. J. Sheets

In 2009 the Gold Quarry open pit mine, located 11 km northwest of Carlin, Nevada, USA, experienced multiple large-scale slope instabilities of the upper east highwall that reduced gold ore extraction for nearly 18 months. The slope instabilities occurred within a weak, consolidated sedimentary sequence that exhibits strength characteristics that are transitional between soil and rock. Instability initiated as mining exposed the lower clay-rich sub-units of the Carlin Formation (Fm.). This deformation created preferential flow paths that allowed groundwater from the upper sandy sub-units to infiltrate low permeability clay-rich sub-units, thereby enhancing deformation of the slope toe which in turn destabilized the upper portion of the highwall. The outcome was a 160 m high slope instability that had a lateral run-out of 850 m. The effort to return the pit to ore production required both the geotechnical and hydrogeological investigations and the preliminary remediation mining activity to be concurrent. This approach required the development of detailed safety procedures and a requirement to modify the remediation design as new results were obtained. An initial challenge was to mitigate a near vertical, 90 m headscarp with blast induced, localized slope failures. Back-analyses applying numerical modeling indicated that the failure surface did not coincide with initial interpretations based on field observations; drilling results eventually confirmed this alternative failure geometry. The final remediation design incorporated shallower slope geometries and an approximately 3 Mt buttress along the base of the Carlin Formation and bedrock contact to reinforce the lower clay-rich sub-units. The outcome is a stable highwall within the Carlin Fm. following nearly ten years of repeated slope instability, and an example of the necessity to conduct appropriate geotechnical and hydrogeological studies during the early stages of a new layback evaluation or new open pit development.

Feb 23, 2014

By S. J. Page

The personal dust monitor (PDM) is a combined tapered element oscillating microbalance (TEOM) respirable dust monitor and cap lamp, configured to have dimensions and weight similar to those of a lead-acid miner’s cap lamp battery. The Higgins-Dewell (HD) cyclone design operated at 2.2 L min-1 airflow has previously been reported to have low bias relative to the International Organization for Standardization (ISO) convention. Previous reports have described the PDM as meeting the NIOSH Accuracy Criterion. In order to avoid certain analysis anomalies encountered during these evaluations, a different method of establishing the PDM relative standard deviation was employed. Re-analysis of laboratory data for both the early prototype and precommercial PDMs indicates that the PDM still meets the NIOSH accuracy criterion, and that the precommercial PDMs are more accurate than previously reported.

Jan 1, 2011

By J. A. González-Anaya

This laboratory work presents a study of the effect of ultrafine grinding on the gold recovery of a highly refractory gold concentrate. The particle size of the concentrate was P80 = 46 µm and the main species present were quartz (28.58%), dolomite (25.63%), pyrite (20.93%), arsenopyrite (15.39%) and 112 g/t gold. After optimizing hydrated lime and lead nitrate additions, standard cyanidation with 1% NaCN, pH = 12.3, 25% S/L permits to recover only 9.4% of the gold. Different particle sizes were submitted to cyanidation. When the concentrate was ground to ultrafine sizes (P80= 4.6 µm), the gold recovery for the same cyanidation conditions increased to 67%, with cyanide consumption of 66.7 kg NaCN/t. Additional tests were performed in order to reduce the cyanide consumption. The reduction of the cyanide concentration in the leaching solution from 1 to 0.5% and the addition of 100 g Pb(NO3)2/t allowed the reduction of the cyanide consumption to 27.6 kg NaCN/t (58% reduction), while maintaining the same gold recovery of 67%. The remaining gold could be present as very fine inclusions or in solid solution in the matrix.

Jan 1, 2011

By R. C. Kellner

Duval Sierrita Corporation, a wholly-owned subsidiary of Duval Corporation, operates an 86,000 STPD copper-molybdenum concentrator near Tucson, Arizona. Shortly after production commenced in February, 1970, it became apparent that the reduction crushing system represented a limitation to reaching the design capacity of 72,000 STPD. The development work performed on the reduction crushers in order to first meet design capacity, and to subsequently increase production to 86,000 STPD is described in this paper. The Sierrita plant is a conventional three stage crushing sys- tem. All crushers were supplied by the Allis-Chalmers Corporation and consist of two 58 x 89 Superior gyratories, four 138b EHD hydrocones, and ten 384 hydrocones. Screening is performed prior to and subsequent to secondary crushing and in closed circuit with the tertiary crushers. Typical throughput rates and equipment sizes are presented in Figure No. 1.

Jan 1, 1975