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By B. G. Stone

"INTRODUCTION “Sampling is the process of taking a small portion of an article such that the consistency of the portion shall be representative of the whole” (Baxter and Parks, 1939) “An orebody is a mixture of minerals in proportions that vary in different parts of the mass. As a consequence the proportion of contained metals also varies from place to place. Therefore, a single sample taken in any particular place would not contain the same proportion of metals as does the orebody as a whole except by a highly improbable coincidence. The probable error, which would be very large if only one sample were taken, decreases with the number of samples, but it never disappears completely unless the samples are so numerous and so large that their aggregate is equal to the orebody itself, in which case the orebody would be completely used up in the process of sampling. Since carrying sampling to such an extreme would defeat its own purpose, some probable error is always present in actual cases and the practical objective is to reduce this probable error to allowable limits. This means balancing the number of samples against the desired accuracy; if there are not enough samples the result is unreliable; if there are too many, the time and expense of taking them is excessive.” (McKinstry, et al., 1948). In an actual orebody, the accuracy of sampling depends not alone on the number of samples but also on proper distribution of them throughout the orebody, for it would obviously be incorrect to take all of the samples either in a rich part or a lean part. Therefore it is important to select the places in such a way that all parts of the orebody will be represented. “For those who cultivate land which is alike arid, heavy , and barren, and in which they sow seeds, do not make so great a harvest as those who cultivate a fertile and mellow soil and sow their grain in that. And since by far the greater number of miners are unskilled rather than skilled in the art, it follows that mining is a profitable occupation to very few men, and a source of loss to many more.” (Georgius Agricola page 5 Book 1 as translated by H.C. Hoover and Lou Henry Hoover, 1950)“It is evident that mining is very profitable to those who give it care and attention”"

Jan 1, 2015

By C. Frenzel, N. Blechschmidt

"INTRODUCTION There is no doubt about the time and effort companies put in establishing and maintaining their equipment. However, the question about how these companies can map the benefits comes up. Neither do they have the tools to quantify the benefit of their action, nor do they have the tools to know the actual quality of their current maintenance system. The resources used in the process seem futile to observers. It seems impossible to trace improvements and to get information about the impact of actions in retrospect. Improvements in maintenance performance cannot be recognised by management or shareholders. Thus the necessity for measuring the performance of maintenance systems is given. In this paper ConMoto is systematically showing the strengths and weaknesses of many companies' maintenance management and is providing field-tested proven design elements for measuring maintenance systems and implementing Value Oriented Maintenance. Considering only business assets in production facilities and related machinery out of all investment goods in Europe, you reach a value of around 9.7 trillion euros in 2008. In Germany alone the equipment replacement value amounted to about 1.9 trillion euros [8,10,11,13]. If you calculate a cross sector maintenance costs rate of 4.8 % (corresponding to the average value identified in this study), direct maintenance costs in European production locations add up to over 450 billion euros per year [3]. These figures speak for themselves. Yet maintenance is not only of enormous significance for European enterprises. Our experiences show that maintenance and asset management, particularly sustainability issues, are also increasingly moving to the forefront in the BRIC states, in the Middle East and in many emerging countries. First of all, in order to meet the resulting high quality and cost related requirements of maintenance systems, a comprehensive overview of the issue is needed. This overview is provided by a detailed analysis of 83 companies and production plants from various sectors – with amazing results. SIGNIFICANCE OF MAINTENANCE Current studies show the high financial significance of maintenance and asset management. According to the market study in the Asset Manager [9], in industrialised countries about 10 to 15 per cent of the labour force are employed in maintenance and facility management tasks. In Europe about 40 to50 million people are directly and indirectly involved in retaining the value of machinery, plants, buildings, transport systems and infrastructure facilities. A glance at the costs side also demonstrates the great relevance of maintenance. EU-wide annual direct maintenance costs amount to a total of more than 1,500 billion euros. In Germany alone they are about 250 billion euros. This impressive total is considerably exceeded by indirect maintenance costs caused by technical failures. Indirect costs are estimated to be five times higher (Figure 1). [7,12,14]"

Jan 1, 2018

By John G. Holmes

The generation of low cost power is but one phase of the TVA program for regional development. During the 36 years since TVA began, growth in its generation of electric power has necessitated a shift from a predominantly hydroelectric power system to a combination steam and hydroelectric system. The addition of steam-electric power plants to TVA's generating system was necessitated by the rapid increase in the traditional and defense demands for electric power in the 80,000-square-mile area served by TVA, the need to firm up the hydroelectric power, and the fact that all available sites for sizeable hydroelectric projects had been developed. At present TVA owns and operates 40 power plants--29 hydroelectric and 11 steam-electric plants. The total generating capacity of the hydroelectric plants is 3,105,430 kw, and the capacity of the steam plants is 13,951,135 kw. This provides a total generating capacity of 17,056,565 kw for the plants operated by TVA. Individual capacity of the 112 hydroelectric units ranges from 10,000 to 67,500 kw, and the individual capacity of the steam-electric units now in operation ranges from 60,000 to 950,000 kw. In addition to this generating capacity, TVA distributes the power from 6 U. S. Army Corps of Engineers hydroelectric plants on the Cumberland River. These plants contribute an additional 725,000 kw. Also, under an agreement with the Aluminum Company of America, TVA directs the stream flows and generation of their 423,715-kw system on Tennessee River tributaries and shares with Alcoa in the increased generation resulting from this coordinated operation.

Jan 1, 1969

By David A. Greenhut

The Kubota surface melting system has been under development since 1975. It has found commercial application on the melting of municipal sludge, and ash from solid waste. The melted product has physical properties allowing its use as a substitute for aggregate in cement and asphaltic construction. This paper describes the surface melting system, its current use and anticipated future use.

Jan 1, 1991

By David Yankovich, Geoff Hughes, David Haug, Jon Kaneshiro

"In March 2013, the Sanitation Districts of Los Angeles County began final design of the Joint Water Pollution Control Plant (JWPCP) Effluent Outfall Tunnel project. The new, approximately 7-mile, 18-ft internal diameter tunnel will provide additional capacity and redundancy for the existing 8- and 12-foot diameter tunnels, which were built in 1937 and 1958, respectively. Connections to an existing, active 14-foot arch force main and four existing ocean outfalls ranging from 5- to 10-foot diameter are required. This paper will present geological features for the project, and details of the proposed post-tensioned tunnel liner and associated structures. INTRODUCTION The Sanitation Districts of Los Angeles County (Sanitation Districts) are 23 independent special districts serving approximately 5.3 million residents in Los Angeles County. Seventeen of the districts that furnish sewerage services to the metropolitan Los Angeles area are signatory to a Joint Outfall Agreement that provides for a regional, interconnected system of facilities known as the Joint Outfall System (JOS). The JOS service area is shown in Figure 1. The JOS serves an area that encompasses 73 cities as well as unincorporated territory and parts of the City of Los Angeles. The JOS provides wastewater collection, treatment, reuse, and disposal for residential, commercial, and industrial users, and it includes seven treatment plants, the largest of which is the JWPCP, located in the City of Carson. Currently, secondary treated effluent is conveyed through two 6-mile long parallel tunnels, 8- and 12-feet in diameter, from the JWPCP to a manifold structure located at Royal Palms Beach, near White Point on the Palos Verdes (PV) Peninsula, from which four seafloor outfalls extend offshore. The two main outfalls, 90- and 120-inches in diameter, extend approximately 1.5 miles offshore and discharge at a depth of approximately 200 feet below sea level. The other two outfalls, 60- and 72-inches in diameter, are used for additional capacity during heavy rain events and extend a shorter distance offshore and discharge at shallower depths. A schematic of the existing system with the proposed tunnel and structures is shown in Figure 2, and the proposed 18-ft diameter tunnel alignment is shown in Figure 3. Both existing tunnels and main outfalls are required to be in service at all times."

Jan 1, 2016

By Mark J. Zdunczyk

"Frac sand is industrial silica sand much like glass, foundry, filtration and blast sand. The sand must meet certain specifications set forth by the industry that consumes the product. The production and consumption of frac sand has experienced record growth in the last 10 years because of new oil and gas drilling, new horizontal well drilling, multi-stage fracturing and the stimulation of older wells that have little or no production. Frac sand is needed to “prop open” the fractures in the rock reservoirs to allow oil and gas to flow out more freely.According to the U.S. Geological Survey (USGS), the estimated production of frac sand in 2015 was 71 percent of the total production of industrial silica sand or 67.4 Mt (74.3 million st). This is a decrease of about 12 percent from 2014. However, the silica sand industry and other industry sources estimate only 50 Mt (55 million st) of frac sand were produced in 2015. In recent years both the USGS and industry studies have been very close in estimating the production of frac sand but with the recent downturn in frac sand production, perhaps, reporting to the USGS was not as accurate. These discrepancies may be that the USGS statistics are based on voluntary reporting by the industry and some companies report their approximate production, others may not. It is always difficult to obtain accurate production figures of any industrial mineral or construction aggregate operation as most companies tend to keep those figures somewhat confidential. It is certainly accurate to report that the production of frac sand had decreased since the last quarter of 2014 and through 2015. The oversupply of oil and natural gas has led to this decline in frac sand usage. Oversupply has idled drilling rigs and well completion activities. World Oil Magazine reports that 2015 was the worst year for rigs in a quarter century. The only wells being completed are those that have contract agreements to do so, others have been capped. Very few new wells are being drilled. Since about 98 percent of well completion is sand and water, the sand supply has caught up with the demand. There are some bright spots in the “oil patch” as the Permian Basin in Texas and the Woodford Shale in Oklahoma have kept pace somewhat with drilling and completion. It has been reported that the frac sand producers in the Brady-Voca, TX area are producing to nearly capacity. The northern frac sand producers like those in Wisconsin, Illinois and Minnesota are feeling the downturn because of the cost of shipping sand to these moderately active basins and plays. The “rule of thumb” is that freight is 2/3 and sand is 1/3 the cost."

Jul 1, 2016

By Alain S. Kivava, Olawale K. Aromolaran, Charles Nzolang, Anthony T. Bolarinwa, Georges M. Kasay

Rare earth elements (REEs) are crucial in high-tech and green technologies. The Democratic Republic of Congo (DRC), rich in mineral resources, shows potential for REE deposits in carbonatites, pegmatites, and placers. This paper reviews global REE resources, highlights potential REE targets in Africa, and emphasizes the need for further research and exploration in the DRC to unlock its REE potential.

Feb 4, 2022

By D. McCarthy

This paper discusses the process involved in developing an optimum method of treating and removing heavy metals from water that have leached out from the native rock -prior to discharge back into the environment. Also designed into the system is a manner to stabilize the metals removed as a precipitate, so that they can be disposed of as a non-hazardous waste.

Jan 1, 1992

By Q. Feng

Study has been carried out to apply fly ash as a high strength, water-resistant precast construction material through geopolymerization. Experiment results show that the working conditions such as water content, the concentration of NaOH, curing temperature and curing time, significantly affect the mechanical property of geopolymer matrix. Through optimization, an above 100 MPa compressive strength has been achieved with the geopolymerization products. Water soaking tests show that the geopolymerization product has a very high water resistance without losing noticeable compressive strength even after a one month soaking time. To elucidate the geopolymerization mechanism, microscopic techniques such as SEM/EDS and XRD are also applied to investigate the microstructure, the elemental and phase composition of geopolymerization products. The findings of the present work provide a novel method to apply fly ash as a high strength water-resistant precast construction material. INTRODUCTION Geopolymerization is a process of obtaining a polymeric structure from aluminosilicate by dissolving aluminosilicate sources in a strong alkali (NaOH) solution and condensation of free [SiO4] and [AlO4] tetrahedral units (Davidovits, 1985 and 1988; Duxson et al, 2005; Xu et al, 2000, 2002). After being cured at an elevated temperature for a specific time, the geopolymerization product shows a greatly increased compressive strength. Therefore, the product can be used as construction material such as bricks and road pavement. It provides a very promising method to apply aluminosilicate sources such as fly ash as a construction material for a sustainable development. Fly ash is a main industrial waste which needs to be carefully impounded because of its potential impact on environment. Many efforts have been tried to utilize fly ash as construction materials substituting Portland cement because of the following reasons. First, fly ash is a silica/alumina rich aluminosilicate source, which makes the specific material an ideal source for the geopolymerization process. Secondly, the particle size of fly ash is usually very small (< 50 microns) and it saves a lot of energy consumed during the production process of cement for grinding. Thirdly, fly ash is an ideal source for geopolymerization because it is reactive to alkali even at a mild temperature. In the past twenty years, many studies have been carried out on the geopolymerization of fly ash to a make construction material. However, there are some disadvantages associated with the conventional methods of treating fly ash (Palomo et al, 1999; Perera et al, 2007; Temuujin, et al, 2009; Hanjitsuwan et al, 2014). First, in most of the proposed geopolymerization methods, a salient amount of sodium silicate has to be added. It therefore makes it complex whether the achieved mechanical strength of geopolymerization products is due to a real geopolymerization process between fly ash and alkali or just largely the solidification of metal silicate in air at an elevated temperature. Secondly, the authors have noticed that when the geopolymerization product is soaked in water, the solution pH increases sharply and the products will lose its compressive strength gradually in water. Thirdly, the compressive strength of the geopolymerization product as reported is usually less than 50 MPa.

Jan 1, 2019

By Jeff Reid, Mohamed Maghari, Nicholas Joens

The Burnaby Mountain Tunnel was an integral part of the Trans Mountain Expansion Project. General Contractor, Kiewit Ledcor TMEP Partnership (KLTP), contracted with McNally Construction to build an underground tunnel between the Burnaby and Westridge Marine terminals under Burnaby Mountain. The pipeline was constructed within a 2.6-kilometre tunnel, eliminating the need to run the pipeline over the mountain and minimizing community impacts. The complexities of this Project led to multiple innovations, including the design of a Tunnel Boring Machine (TBM) capable of excavating through mixed-faced conditions concurrently thus allowing the Project team to complete the tunnel with limited geotechnical information.

Jun 23, 2024

By Howard N. Egan

The importance of coal as the major energy source has led to wider interest in the recovery of waste coal fines as a usable product. An additional incentive for fine coal recovery has been the increased emphasis on environ- mental pollution control and conservation of the nation&apos;s natural resources, Accordingly, a series of studies and tests were performed to investigate the feasibility of the recovery, concentration, balling and pelletizing of coal fines as a marketable adjunct to existing mining and beneficiation operations. These studies were conducted at the existing operations of the Eastern Coal Corporation at Stone, Kentucky, and the Metallurgical Laboratory of Arthur G. McKee & Company in Cleveland, Ohio. The purpose of the investigations was to recover the fines from the effluent waste waters of an existing preparation plant and transform them into a high carbon, low sulfur and ash product capable of being handled with a minimum of degradation and dusting problems. The fines were relatively high in ash content prior to processing, and flotation pretreatment served a combined function of beneficiation, recovery and water clarification, The minus 28 mesh coal concentrate containing 40 to 45 percent minus 325 mesh size material had an ash content varying between 5 and 7 percent and a sulfur content of less than 0.5 percent. Chemical and size analyses of the effluent and concentrated fines are presented in Table I for comparison.

Jan 1, 1967

By S. Dixon

The use of warm (40-50°C) solution for the selective elution (pre-strip) of copper cyanide from gold and silver cyanides adsorbed on activated carbon was found to elute +90% of the adsorbed copper compared to the use of ambient (20°C) solution eluting 50-70% of the adsorbed copper. The warm solution pre-strip elution did have higher co-elution of gold (1-4%) and silver (10-18%) with the copper. The use of ambient solution pre-strip elution co-eluted less gold (0.2%) and silver (2%).

Mar 2, 2022

By Christopher J. Bise

It is somewhat reassuring to note that the United States has an abundance of coal reserves which can be used to bridge the widening gap between the nation&apos;s energy production and consumption. The U. S. Bureau of Mines has recently established a demonstrated coal reserve base of 434 billion tons. (31)(Figure 1) As can be observed, the major percentage of the reserves is in the West. Although surface coal mining in the West has been gaining increased attention in recent years, western reserves that must be deep mined are significantly greater. Though deep mining activity in the west is very limited and accounts for less than 2% of the annual production, the primary reason, quite probably, is the greater thickness of the seams as compared to those found in the East. Forty-five billion tons of the western demonstrated coal reserve base for underground mining are in seams greater than 10 ft. in thickness. (37) Thick coal seams do not lend themselves readily to extraction with the underground mining methods practiced in the United States today. Experiences from the practices in other countries can serve only as guidelines. Consequently, a concerted effort is necessary to overcome the technical difficulties.

Jan 1, 1975

By Shawna Von Stockhausen, Hong Yang, Tung T. Vu, Derek Penrice, Kevin Huynh

"The Regional Connector Transit Corridor is a 1.9 mile long light rail transit project in downtown Los Angeles, California. The project includes approximately 4,930 feet of twin bored tunnels together with a mined crossover cavern, 3 deep stations, and other cut-and-cover structures. The bored tunnels will be excavated using an earth pressure balance tunnel boring machine through Fernando Formation (extremely weak to weak rock) and alluvium. The tunneling will be performed in close proximity to a large number of existing structures, including the existing Metro Red Line tunnels with as little as 6 feet of separation. Thus, the evaluations of the tunneling effect on these structures and the instrumentation and monitoring program is an essential part of the project design. This paper provides a very brief overview of the considerations and evaluations of the tunneling effects on the existing structures and results of evaluation obtained during the final design stage of the project. INTRODUCTION The proposed Regional Connector Transit Corridor (RCTC) project provides a 1.9 mile-long connection between the Metro Gold Line from Pasadena and East Los Angeles; and the Metro Blue Line to Long Beach and the Expo Line to Culver City. The alignment is shown in Figure 1. The Regional Connector will provide new tracks through downtown Los Angeles. The project will extend underground from the Metro Blue, Expo, Red, and Purple Lines’ 7th Street/Metro Center Station following Flower Street, curving northeast to the north of 3rd Street under the 2nd Street Tunnel. The alignment will then continue eastward under 2nd Street, turning northeast to cross under the intersection of 1st and Alameda Streets, then splitting into two branches above the ground surface, one branch extending north along Alameda Street and the other extending east along 1st Street. The project elements include 3 deep stations, a SEM cavern, segments of TBM bored tunnels, and cut-and-cover guideway structures. The bored tunnels have an excavated diameter of 20.3 feet. The subsurface conditions along the tunnel alignment generally consist of artificial fill overlaying finer-grained alluvium (dominantly medium dense to dense sandy soils), underlain by coarser-grained alluvium (a wide variety of medium dense to dense sandy and gravely soils). Below the coarser-grained alluvium is Fernando Formation, which is characterized as extremely weak to very weak sedimentary bedrock. A long stretch of the alignment will be excavated in this formation. The soil layers above the Fernando Formation are of variable thickness and spatial distribution. The geologic profile is shown in Figure 2."

Jan 1, 2016

By R. Brantley Sudderth

There are three broad categories in which most solvent extraction technology can be distributed?: 1) reagents, 2) equipment, and 3) systems. Reagents which are now used in commercial solvent extraction plants are of many chemical types, and each possesses certain properties which make it more economically desirable than another alternative. The equipment which is&apos; used in solvent extraction plants for contacting the organic and aqueous phases and separating the same is varied. Most common to the industry is the mixer-settler unit which in itself, can be of varied design; but many new innovations in contacting and separating equipment have been recently introduced or are :now being studied. Each specific solvent extraction application will often dictate the type of contacting and separating equipment used. Obviously, the trend is toward smaller less expensive equipment which reduces the often expensive organic inventories necessary for most solvent extraction plants. The current thrust of .investigations in ancillary equipment is usually aimed at recovering organic from solvent extraction sludges or from aqueous streams exiting the process.6 This type of equipment helps to reduce the total organic losses from solvent extraction plants and thus reduce the operating costs. The term "systems" in solvent extraction applies to the manner in which a solvent extraction process is carried out. This manner is usually dictated by the properties of the reagent which is used, and it involves a tailoring of the equipment or the process flowsheet. Some of the things which can be tailored are: 1) The aqueous media -whether acidic or basic and what type of acid or base 2) Counter-current or single stage (co-current) contacting 3) EMF or pH control 4) Organic "crowding" alternative 5) Heating or cooling process streams Regardless of the type or extent of tailoring, efforts to do this are usually a result of the low cost of solvent extraction as a unit process.

Jan 1, 1977

By James H. Barks

Commercial development of the mineral resources of southwestern Missouri began about 1850 and spread into southeastern Kansas and northeastern Oklahoma, forming the Tri-State Mining District with Joplin as the urban center (fig. 1). The value of the Tri-State mineral production from 1850 to 1950 exceeded one billion dollars, and until 1945 the region was the world&apos;s leading producer of lead and zinc concentrates, accounting for one-half of the zinc and one-tenth of the lead produced in the United States (Gibson, 1972 1). By 1950 most of the rich ores had been extracted, and mining and milling operations declined during the 1950&apos;s and ceased in the 1960&apos;s. The sulfide minerals, mainly galena and sphalorite, were mined from cherty limestones at depths of 25 to 75 m (meters). Crude ores were brought from the mines to the surface where they were milled into lead and zinc concentrates. , Barren rock was discarded in piles while the ore-bearing rock was crushed and ground into fine gravel. The minerals were separated from the rock by a jigging process and the tailings were skimmed off and discarded in large piles. Ground-water flooding of the mines was controlled by constant pumping. When pumpage declined in the 1950&apos;s and 1960&apos;s tile abandoned mine drifts and shafts filled with water. At present (1977) numerous tailings piles and flooded mines remain as visible evidence of the mining era and as a threat to the quality of ground and surface waters of the area. In 1976 the U.S. Geological Survey in cooperation with the Ozark Gateway Council of Governments made a study of the effects of the mines and tailings piles on water quality in the Missouri part of the Tri-State District. The study area covers approximately the southwestern quarter of Jasper County, an area of about 725 km2 (square kilometers), and is bounded by long 94 o 15&apos; w.&apos; and the Missouri-Kansas state line, and lat 37 o 15 N., and the Jasper-Newton County line.

Jan 1, 1977

By Samuel Frimpong

The preparation of graduate talent for the mining industry is a challenging process, given the multifaceted and complex array of decisions mining engineers make in discharging their responsibilities. As leaders, mining engineers must manage operations, lead project teams, mentor junior engineers, chart the technological directions of companies and deal with several organizations for maintaining the technical and economic feasibility of operations within strategic and tactical framework. Traditionally, the completion of the bachelor of science degree curriculum, with a minimum cumulative grade point average (CGPA), has been used as a graduation measure by Missouri University of Science and Technology (Missouri S&T). Companies have long realized the limitations of the CGPA for recruiting graduates because mining engineering is an applied engineering discipline. Company recruiters have sought to correct the limitations by factoring experience and behaviors into the selection process when recruiting knowledgeable and well-rounded graduates. In this paper, the authors introduce a new metric, which combines the current CGPA (knowledge) with experience and attribute (KEA) metrics to gauge the job readiness of graduating engineers. The KEA metric, also called the job-readiness factor (JRF), is the sum of K (50%), E (30%) and A (20%). The KEA process has been applied to a graduating class in Missouri S&T to demonstrate the value of the new metric system. The results show a fairly positive correlation between CGPA and the KEA metric, with a coefficient of determination of about 70%. Overall, the KEA metric system provides a better picture of the capacity and job readiness of graduates entering the workforce.

Jun 1, 2013

By G. Righettini, P. Mousset-Jones

Diesel powered vehicles have made underground mines more efficient, but with the advent of DPM regulations, in most cases, extra ventilation and/or engine emissions control technology will be required. Using fuel cell powered vehicles will not need these measures to be taken. Nine US underground mines of varying production rates and mining methods were studied to determine possible ventilation reductions if their diesel fleets were replaced with identical fuel cell powered vehicles. Factors that might limit ventilation reductions, such as heat and the effects on other pollutants were determined for each mine. The ventilation cost savings and other benefits of fuel cell vehicles show that when they become commercially available they have the potential of being viable alternatives to diesel vehicles.

Jan 1, 2004

By G. Whitney, J. Steiner

Introduction The Summitville Mine located in southwestern Colorado is an example of the potential impact that natural weathering and mining activities can have on environmental quality. Acid rock drainage and metals leaching from active and historic mine districts are a major environmental problem facing the mining industry today. Sulfide ore exposed naturally or during mining operations has the potential to produce leachates that contain high concentrations of dissolved metals. These leachates can affect the quality of plant and animal health in surface water used for agriculture, recreation and human consumption. Pintail Systems has developed biological processes for detoxification of cyanide in heap-leached spent ore and process solutions. During application of spent ore cyanide bio-detox processes we have also observed a substantial reduction in many of the leachable metals in biotreatment solutions. These field observations of soluble metal reduction led us to propose that metal bio-mineralization should be a secondary treatment goal of spent ore detox in Focused Feasibility Studies (FFS) for the Summitville Mine. In the FFS (described in a companion paper) for Summitville, spent ore from the heap leach pile (HLP) was loaded into PVC test columns (six inch X ten foot) and was leached with bacteria/nutrient solutions. Two treatment designs were studied: a standard percolation leach (aerobic) and a saturated leach design where the ore was saturated with the heap leach solution to which bacteria and nutrients were applied in a continuous biotreat leach. The bacteria for all column treatment tests were isolated from the spent ore at depth through the Heap Leach Pile (HLP) in the saturated and unsaturated zones. Bacteria isolated from the heap material were tested for cyanide oxidation capacity and were submitted to a bioaugmentation program to improve reaction kinetics and metals tolerance. The final treatment population consisted of several distinct species including aerobic heterotrophs, facultative anaerobes and sulfate-reducing bacteria. The remineralization of soluble metals was observed through a decrease in copper in column leachate solutions and the formation of observable mineral products on ore surfaces in the columns. Several of the tests were run in clear PVC columns to facilitate observation of mineral formation. The column ore contents were photographed before, during and after the biotreatment process which ranged from 10 to 20 days for each test column. Ores were collected from each column after the treatment was complete and were submitted for SEM and TEM study at two laboratories - the USGS SEM Laboratory in Denver, Colorado and the City College of New York SEM laboratory. Treatment Process Description Numerous species of bacteria, fungi and yeasts are capable of accumulating many times their weight in soluble metals. Both living and dead biomass are effective in removing soluble metals from waste streams containing gold, silver, chromium, cadmium, copper, lead, zinc, cobalt and others. Soluble metals may also be immobilized in soils by natural or engineered biomineralization reactions. Several commercial processes using biological reactions are being applied on an industrial scale for metal remediation. Bacteria found in natural and extreme environments have developed a wide variety of metabolic functions to adapt to these environments. These natural microbial functions contribute to global mineral cycling that continuously forms, transforms and degrades minerals and metals in the environment. Biomineralization is described as a surface process associated with microorganism cell walls where the remineralization occurs. The biogeochemical activities initiated by microorganisms in ores, soils, surface and groundwater environments can dominate the formation and transformation of those mineral environments.

Jan 1, 1995

By Peter Kreisman

This paper and four other papers on the MEQB Regional Copper-Nickel Study, presented today at the 1980 SME-AIME Fall Meeting are based on four years of extensive inter-disciplinary research and impact analysis supported largely by the Legislative Commission on Minnesota Resources. This study produced over 180 technical reports, the results of which are summarized in an Executive Summary available from the Minnesota State Planning Agency, St. Paul, Minnesota. Those wishing to examine the many scientific, engineering, environmental, social or economic issues addressed by the study are encouraged to obtain a copy of the executive summary. The executive summary includes a bibliography of all technical reports produced by the Regional Copper-Nickel Study and describes the five-volume, 26 chapter Regional Copper-Nickel Study Report.

Jan 1, 1980