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By K. A. Prisbrey

Mineral carbonation is the reaction of carbon dioxide with mineral silicates to form solid, carbonate compounds. The carbonate ion holds carbon in a low energy state – lower than in carbon dioxide. Thus the reaction of carbon dioxide to produce mineral carbonates captures the carbon in a stable, solid form. The University of Utah is investigating the carbonation of silicate minerals by mechanochemical processing, which has the potential of being much less expensive than other methods. Tests to date have shown that a marked change takes place in the lizardite variety of serpentine after 15 to 20 minutes of intense grinding in the presence of gaseous CO2. Further testing is in progress.

Jan 1, 2004

By Xu Xiaohe, Zhou Jiandong, Luo Shihui, Zhang Liqun

Recently, the research and applications of ES (Expert Systern) have been put forward actively in many mining fields in China. After various ES applications or instances are introduced, the paper has especially focused on the exclusive properties of a mining system different from any other system and the problems of the existing mining ES applications. And a synthesis methodology has been introduced in order to develop a applicable ES application

Jan 1, 1996

By J. D. Miller, Z. S. Nickolov

Sum Frequency Spectroscopy (SFS) is a powerful nonlinear optical technique to study interfaces at the molecular level. SFS has one major advantage over conventional vibrational spectroscopic methods, such as infrared (IR) absorption and Raman scattering, in that the method is inherently interface specific. As a result, the spectroscopy of molecules residing in the interfacial region can be probed selectively without any contributions from the molecules present in the more pervasive bulk phases. Analysis of SF spectra can yield information on population, structure, and orientation of interfacial species with several nanometers in-depth resolution. The recently acquired SF spectrometer at the University of Utah opens new possibilities for investigation of interfacial phenomena of great importance for separation technology, materials research, nanotechnology, bioengineering. Its application to studies of liquid/gas, solid/liquid, and solid/gas interfaces will be discussed.

Jan 1, 2004

By H. Suharyono

The results of an experimental study of polymer-induced flocculation of clay suspensions in continuous, stirred-tank reactors are presented. The effects of polymer dosage, mixing time and mixing intensity are shown to be generally similar to those observed for equivalent batch systems, but flocculation appears to be generally less effective in the continuous process. Settling rates are lower and supernatant turbidities are higher for the continuous system. It is postulated that non-equilibrium effects due to simultaneous polymer adsorption and floc growth can be exploited so as to enhance flocculation in batch systems. The nature of the continuous process, however, offers less opportunity for taking advantage of such effects. Conditions in a continuous flocculation system inherently lead to a closer approach to equilibrium.

Jan 1, 1994

By Thomas A. Colbert

Permanent reclamation of tailing and acid forming mine wastes in the western United States has been largely a losing proposition. There have been few if any successes without actual burial of wastes with soil, overburden, waste rock or other material more amenable to reclamation. Rather than major breakthroughs, development of new techniques has been slow and steady. Revegetation of acid forming wastes with little or no soil cover is now probably feasible. Three key elements include the use of adapted plant species which are now becoming commercially available, lime and selective bactericide for controlling acid, and organic amendments such as manure or sewage sludge. Benefits of this type of reclamation often include reduced mobility of toxic metals and improvements in water quality. With a stringent regulatory regime for mine wastes impending under Strawman II, the importance of good, economical reclamation techniques will become critical to successful and profitable western mining operations.

Jan 1, 1991

By Edward I. Erlich

1984 saw the 30th anniversary of a momentous event in Soviet geology-the discovery of kimberlites in Siberia, an event that vaulted the Soviet Union to second rank among the world's producers of both gem and industrial diamonds. There are many legends associated with this story, legends about those who predicted the discovery and those who achieved it in the field. The story told here unfolded during the field campaigns of the 1940s through 1960s, as witnessed by the authors and their companies of an earlier generation. This story illustrates science, chance, and human emotions at work, resulting in a blend of conviction, courage, bureaucratic sniping, and competition for glory. At the same time, it is an illustration of the workings of the Soviet exploration system. In a broader sense, it is the realization of the Russian image-boundless natural wealth, indomitable ingenuity, and the rigid political economic system that permeates the Russian landscape as well as the people. Most accounts of the Siberian diamond saga begin with statements such as, "This discovery confirmed the predictions of...", or "It was a result of predictions of one of the greatest Soviet geologists, Academician V.S. Sobelov...". These are only part of the truth. It had become apparent even in the 1930s that the Siberian Platform contained one of the Earth's greatest Basaltic provinces, described in a monograph by Sobolev...; and at the end of the thirties, G.G. Moor of the Institute of Arctic Geology found alnoites, similar in many ways to kimberlites. At the same time, the famous polar geologist, N.N. Urvantsev found other kimberlite like rocks in the southern Taymir Peninsula, adjacent to the Siberian Platform. In publications describing these rocks, Moor and Urvantsev mentioned for the first time the possibility of finding diamondiferous kimberlites similar to those in South Africa. Unfortunately, Urvantsev spent little time in the field between terms in concentration camps. Moor was considered by his superiors to be no more than a good descriptive petrographer; they suggested to him that his conclusions should be backed up by more highly regarded specialists. Thereupon, Moor asked Sobolev to coauthor a paper with him and this became the widely quoted prediction about diamonds in Siberia. Another early paper should also be mentioned, an unpublished paper found by M.I. Rabkin in the geological archives of the Norilsk Metallurgical Plant, written by Yu. M. Sheinmann when he worked in the concentration camp there in the late forties. This report placed the probable location of yet-to-be-discovered kimberlites within less than 100 km of their correct location.

Jan 1, 1990

By John Reilly

"INTRODUCTION Successful management of megaprojects, meaning delivery within budget, on time and according to expectations, is a fundamental requirement. Many projects have been successful, some have not. This paper reviews megaprojects1, drawn from the author’s projects over the last 50 years, with “lessons-learned” and a summary of recommendations that, if implemented, would improve megaproject management and delivery. Characteristics of these projects are summarized – including outcomes related to key factors such as politics, management, organizational structure, contracting methods, cost estimates, risk and other elements. The projects include the Washington D.C. Metro, Boston Southwest Corridor, LA Metro, Toronto Rapid Transit Expansion Program, BART San Francisco, MARTA Atlanta, London Underground and the Washington State Highway megaprojects – including the SR520 Floating Bridge and the Alaskan Way tunnel. Other projects that illustrate successful, innovative management and contracting methods include the Madrid Metro (low-cost delivery), the Sydney Northside Storage tunnel (outturn cost, alliancing) and the Lake Mead tunnel (working in partnership, risk management). KEY ISSUES A characteristic of megaprojects is that their complexity increases exponentially with size (Reilly 2010, Galloway et al. 2012). These projects are very visible politically, have many stakeholders who must be satisfied and generally span many years and political election cycles. To be successful they must meet expectations, function efficiently, and be delivered under, at or close to budget and schedule. There is a widely-based perception that large, complex projects are always delivered late, over budget and with problems. Specific examples include projects such as Tren Urbano in Puerto Rico – $1.28 billion over initial budget (+133%), the Silver Line Transitway Project in Boston – $286 million over budget (+90%), the London Jubilee Line Transit Project – 2 years late and £1.4 billion (+67%) over budget, the Channel Tunnel Rail Project – £3.7 billion (+80%) over budget, Denmark’s Great Belt Link rail and road link (54% over budget), the 2003 Woodrow Wilson bridge tender in Virginia (72% over estimate) and Boston’s Central Artery Project – several billion (perhaps 100%) over what would have been a realistic initial budget and years late (Reilly 2001c, 2004a; Salvucci 2003)."

Jan 1, 2016

By J. Iannicelli

High intensity, high gradient magnetic separation can economically remove weakly paramagnetic contaminants down to 0 1 micron from industrial minerals This process is employed by all waterwashed kaolin producers in Georgia where seventeen huge magnetic separators are used to upgrade this product As a result, reserves of kaolin in Georgia have been doubled Design improvements have steadily increased the efficiency of separators and reduced power consumption below 300 KW for a nominal 65 TPH unit Beneficiation of ultrafine minerals is discussed based on pilot plant results on bauxite, ball clay, calcium carbonate, glass sand, talc, and numerous other minerals Operating parameters of the process are reviewed and some alternative equipment configurations discussed

Jan 1, 1983

By Toyohisa Fujita, Mitsuo Mamiya, W. Tai Yen, Hiroki Kogita

Green algae taken from an acidic mine drainage and blue-green algae taken from an alkaline hot spring stream were collected and tested for their ability to recover or remove dilute metal ions. Experimental results demonstrated that unwashed blue-green algae and washed green algae effectively adsorbed base metals ions and eluted them at pH 1. It was also found that washed and dried algae adsorbed precious metal ions more effectively than unwashed algae. For example, the washed and dried blue-green algae was capable of adsorbing 0.31 kg of gold per kg of algae. The gold from tetrachloroaurate solution which was adsorbed on washed blue- green algae was found to change to a metallic state following initial metal binding. In the case of a dilute gold complex solution leached with thiourea, only a small amount of gold could be captured by algae. Further experiments were conducted on components of the algae, such as alginic acid, agar, cellulose and chitin and mixtures of these components, in order to determine their contribution to metal adsorption characteristics. However, a mixture of these two components demonstrated both good adsorption and desorption characteristics indicating an interaction between the individual components.

Jan 1, 1995

By Jaime E. Sepúlveda

Semiautogenous grinding (SAG) operators have been realizing the very significant impact of fresh feed particle size distribution on the mill grinding capacity. In actual practice, this impact may be quite difficult to assess because of the natural process variability that may also involve- concurrently other critical factors such as ore hardness. Recognizing the limitations of the empirical approach, the current publication proposes the use of mathematical models and simulators to explore and assess the net effect of feed particle size only, independent of any other factors. The simulation analysis here reported provides a basis to claim that the size distribution of the particles being ground (simply characterized by a % - 2" or similar measurement) is one of the most relevant controlling variables of the overall mill performance, regardless of the SAG circuit configuration.

Jan 1, 2005

By James S. Hanson

Existing models proposed for the bacterial leaching of metal sulfides generally fail to predict solubilization rates at times greater than a few tens of hours. The reasons for this may be that these models are empirically based and use first order bacterial and chemical oxidation rates. This type of model is satisfactory for short time predictions (on the order of 20 hours) when the bacterially catalyzed dissolution is relatively minor. However, when bacterial action becomes more pronounced, these models consistently predict higher dissolution rates than those commonly observed in laboratory experiments. The present model uses several fundamental chemically and biologically based assumptions to predict the dissolution rate of a chalcopyrite concentrate for extended leach times up to the precipitation of jarosite. The main assumptions made are that Monod growth kinetics prevail, T. ferrooxidans adsorb onto the surface of the mineral (not necessarily mineral specific), and that during periods of high growth oxygen transport may become rate limiting. The model also relies on the energy efficiency of the bacteria in fixing carbon (growth yield) and correlates this value with available surface area of the mineral particles and the bacterial growth rate.

Jan 1, 1989

By M. Selamat, J. Nirdosh, S. V. Muthuswami

High-grade uranium ores of Cluff Lake and Key Lake mines from the province of Saskatchewan in Canada are treated with nitric and hydrochloric acids with the objective of leaching 230 Th and 226Ra simultaneously with uranium to produce environmentally safe mill tailings, h is found that optimum conditions for uranium leaching are 50°C, 4 h, 30% solids in leach slurry and an acid concentration of 1 mol/L for HNO, for both the ores. In the case of HCl, a 3 mol/L acid concentration is needed and addition of an oxidant is required because otherwise 230Th and 226Ra extractions remain poor.

Jan 1, 1990

By Richard Druesedow, Richard Ray

Tests at the VP-5 "C" shaft fan installation of Island Creek Coal's Virginia Pocahontas Mines were performed to determine pressure drop due to the design of the shaft collar and ductwork leading to the fan. Data from the test locations in the shaft, duct and fan indicate significant pressure losses in the system as well as significant turbulence in the flow. Data taken with a 3-D probe in the fan annulus confirmed the importance of using this type of instrument in turbulent flow applications. This data will be later supplemented with data taken after addition of turning vanes in the 45° turn adjacent to the fan inlet.

Jan 1, 1993

By M. Szatkowski

The studies conducted by Laplante and coworkers (1983,1984) with flotation of galena and quartz, showed that the rate of flotation reaches a maximum value for a certain intermediate value of the air flow rate. A similar, though less pronounced, effect of the air flow rate on the selectivity was also observed. Luttrell and coworkers (1985) showed that the size of air bubbles has a significant effect on both rate and selectivity of coal flotation. These two studies used flotation tests in which no froth layer was formed. This note describes effects of the air flow rate and bubble size on the rate constant and selectivity of coal flotation, using a mechanical laboratory machine with a froth layer allowed to form. Experimental A raw, dry ground Illinois coal was used in flotation tests. The size distribution and ash content of the samples are : Particle size (µm) Weight (%) Ash (%) +600 4.30 41.7 600/200 43.05 19.0 200/74 22.25 16.0 - 74 30.40 24.0 average 20.8 No. 2 fuel oil with a concentration of 200 g/t of feed and M.IBC with concentrations of 11, 22, and 33 mg/L of pulp (128, 256, 384 g/t, respectively) were used as flotation reagents. Tap water with a natural pH of 7.0 to 7.8 was used throughout the tests. No other reagents were used. The starting concentration of coal in the pulp was 86 g/L. A standard flotation machine with the pulp volume of 5 L was used in experiments. Three different air flow rates were employed, resulting in three air escape velocity values of 14, 30, and 70 cm/min. The air escape velocity (AEV) was calculated as the ratio of air flow rate (Qa) to the slurry surface (Ss) in the machine. For a comparison, the upper limit of air escape velocity values used in commercial size flotation machines is between 70 and 100 cm/min (WEMCO, 1983). A machine consisting of a generator of fine bubbles and a separatory column, described elsewhere (Szatkowski and Freyberger, 1985), was used for some tests where bubble size lower than that generated in the standard machines was required. Prior to a flotation test, a batch of coal was mixed with water in the flotation cell for at least 10 minutes to ensure that all coal was thoroughly wet. Then the specified amount of fuel oil was added and the pulp was conditioned for five minutes. The specified amount of MIBC was added 15 seconds before the end of conditioning. After air flow was opened, flotation products were collected for 0 to 30, 30 to 60, and 60 to 120 second intervals. Content of the combustible material in samples was determined by subtracting the ash content from 100%. A photographic technique was used to determine initial distributions of bubble size generated by the flotation machines. Bubbles generated in water containing the prescribed amount of the frother but no solids were photographed against a black background. The average diameter and standard deviation were then calculated for each set of flotation conditions. The method gives results reproducible within k 5% of the average bubble size. Table 1 contains information about the measured bubble size distributions expressed by the average bubble diameter (Db) and the standard deviation ( SD ) . Results and discussion The general formula for calculating the flotation selectivity is: o = recovery of coal/recovery of ash (1)

Jan 1, 1988

By K. Irmscher

During the last years, using modular computer models on the software and distributed computer capacities on the hardware side has become quite common in the mining industry. When tackling real mining problems under the condition of heterogeneous systems, however, some problems become obvious: the incompatibility of the heterogeneous platforms in connection with the heterogeneously structured information and the necessity of interpreting the data. Knowledge based approaches are employed for solving different planning problems in the field of mining industry. The main problems here consist in the knowledge representation and data acquisition. Starting point of the investigation form classifications of mining planning problems and the corresponding models which can be transformed into information models for evaluation. With help of an expert system a practical solution is represented. Distributed systems with mobile computing and communication facilities for immediate access can be used as an additional support for planning and processing. On the base of public or private computer networks (including mobile networks) the foundation is given for a computer supported treatment of planning tasks. Additionally the use of teleworking scenarios in regions of mine planning and data collection in geological applications is prepared. Foundation forms a workflow system on an object-oriented distributed platform.

Jan 1, 1996

By Ken A. Phillips

Like the Arizona jeans commercial says: Arizona's not just a state, its a state of mines. Nearly 300 mines operate in Arizona making it the largest nonfuel mining state in the nation. Although copper is king in Arizona's mineral complex, nonmetallic minerals play important roles both regionally and nationally. Throughout Arizona's mineral resource development history industrial minerals have dominated over the metals for most, but not recent years. The State's metal mining industry which makes Arizona the number one mining state in the United States is a relatively young phenomenon. Arizona was an important industrial mineral producer long before her metal mining industry got started. Salt, phosphates, silicates, and oxides as food additives, tanning chemicals, gemstones, components of aboriginal ordnance, pigments, and construction materials are among the minerals produced long before copper, gold, silver, and the other metals became important. Around 92 % of Arizona's mineral industry is made up of nonfuel minerals, 86 % of that is accounted for by copper. Another 4 % is taken up by copper byproducts of molybdenum, silver, and gold. The remaining 10% of the production is occupied by non-fuel, non-metallic minerals. Arizona's 1994 industrial mineral production of nearly $380 million ranks us among the top 25 in the nation and higher than the total mineral production of at least 15 states.

Jan 1, 1996

By D. M. Galbraith

British Columbia's physiography - the mountains, valleys and watercourses - provides the basis for rich and varied plant and animal resources and for complex land uses. Mining alters the physical environment in a manner that may create a disproportionate impact on biological resources and land use systems. The object of environmental legislation is therefore largely the protection of the basic physical environment: land surface, water, and air. The pace of mineral exploration, placer mining, and underground and surface gold mining has recently quickened in British Columbia, testing the ability of both industry and regulatory agencies to respond to legislative requirements. Some parameters of mining activity have critical significance for environmental protection, for example: the area disturbed; the physical and chemical qualities of ore, waste and overburden; and the nature of materials handling. Acid mine drainage is a particular hazard. Provincial legislation that applies to mining includes the Mines Act, the Environment Management Act, the Waste Management Act, and the Water Act. Government of Canada legislation includes the Fisheries Act and the Metal Mining Liquid Effluent Regulations. Every new mine proposal in British Columbia is reviewed in the Mine Development Review Process, which receives its mandate from the Provincial Environment and Land Use Cabinet Committee. The proponent submits reports to the Mine Development Steering Committee in succeeding stages: Prospectus, Stage I (after which approval-in-principle may be granted by ELUC); and if necessary Stage 11. Stage 111 is the

Jan 1, 1987

By Robert Sutton, Milan Sjaus

Conveyor pulleys are an important and integral component of a conveyor. Conveyors work in sequence to make up conveyor systems. Each conveyor system is only as reliable as its crudest component. If the pulley fails, then the whole material handling system stops. So what is the effect of this downtime? What are the costs of repair? How much are we willing to pay to solve the problem? What should we spend to prevent an unscheduled shutdown? Do we use the technological improvements at our disposal or do we ignore them to satisfy immediate cost savings? This study will focus on the cost of pulleys relative to the total conveyor cost, the cost of downtime, the maintenance costs and the costs for resolution of the problem. Some philosophic and design concepts are injected for illustration and discussion.

Jan 1, 2000

By R. E. Weeks, D. J. Millenacker

Utilization of true in situ technologies for mining copper in Arizona will involve a complex environmental permitting process. This process is a key factor in determining the feasibility, costs, and implementing time- frames required for development of this innovative mining method. The regulatory structure in Arizona is presently changing due to enactment of the Environmental Quality Act (EQA) of 1986 and development of new aquifer protection rules and regulations. The US Bureau of Mines has reviewed the comprehensive hydrogeologic characterization, ground water monitoring, mechanical integrity testing, well construction, contingency planning, and other regulatory elements that will serve as mechanisms to assure protection of ground water resources. The purpose of this paper is to inform the domestic copper industry of the significance of the new Arizona regulatory structure and its implications for prospective in situ operators.

Jan 1, 1987

By Liyan Ren, Huayang Dai, Yingcheng Li, Enquan Wang

"Three-dimensional geological modelling of coal mines is critical to the sustainable development of the mining industry. On the basis of comprehensively analyzing 3D geological modelling methods, according to the available data of mine such as geological terrain maps, cross-sections and boreholes, we present a 3D modelling method by integrating ArcGIS and 3D GeoModeller. Our motivation is to integrate the advantages of both software modules in processing, converting, integrating and transferring geological information. Special attention has been given to the data structure and processing flow. We build a 3D geological model of the Xieqiao coal mine and successfully extract the geological framework of the strata in the 11118 workface, which is consistent with that of the actual explored geology.Introduction/Background Pertinent impediments such as a lower information degree, the out-of-date information infrastructure and the low level of information management and decision-making make it critical for there to be improvements in mines. Modern exploration technologies favour the construction of digital mine. Digital mine promotes the transformation of the mining industry by integrating information, automation and intelligence to build safe, efficient, high-yield, green and sustainable mines. Three-dimensional geological modelling and visualization of mines are at the core of digital mine. Compared with traditional 2D geological data, 3D models express the various geological phenomena completely, as well as reproduce the spatial distribution of geological units quickly, allowing for the prediction of mining subsidence, better decision-making and improved geological analysis. Modelling methods such as multi-DEM, tetrahedral grid and the generalized tri-prism that are based on borehole estimation and interpolation data are used to construct 3D models of mine geology (Chen 1995,Wang et al 2003, Wu 2004a); nevertheless, these methods cannot fully use multi-source mining data, whereas multi-source integration methods can be used to build 3D models (Kaufmann and Martin 2008, Zhao et al 2009) but require user interaction in model construction and low automation in model updates. During coal production, a plethora of geological data is accumulated. The organisation of discreteinformation under dynamic conditions and the extraction of meaningful information to better service for three-dimensional modelling is a meaningful work (Wu et al 2004b)."

Jan 1, 2017