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By Paul C. Schmall, John F. Donohoe, Arthur B. Corwin

In the aftermath of the September 11th attack on the World Trade Center, groundwater control was of immediate concern. Water in?ow from the adjacent Hudson River through the compromised slurry wall ‘bathtub’ surrounding the site, ruptured water and sewer mains, and saturation from fire hoses all contributed to an already critical situation, further hampering the recovery and rehabilitation effort. An extensive pumping and deep well installation program was initiated, focused on reducing the hydrostatic loading to the severely damaged perimeter slurry wall.

Jan 1, 2003

By Mike Tracy

This section of the Handbook deals with general principles to be evaluated in the development of a mining operation. It addresses the major issues that must be examined to fully evaluate a mining venture. Of course, one of the main topics to be evaluated is mine planning, which is covered in more detail in other sections (13, 17) of the Handbook and should be referenced in mine development projects. The topics to be discussed in this introduction include equipment and supplies, infrastructure, utilities, and project management. In any of the aspects mentioned, the current existing conditions at or near the mine site must be evaluated. This will include assessment of current use of utilities, infrastructure, housing, equipment suppliers, etc., as well as anticipated growth, both in the supply aspect of these systems as well as projected usage on these systems. After full assessment of both these aspects, an evaluation must be made as to the requirements the project will place on these items. Assessment must be made as to any up-grades required to bring the project on line, what impact the project will have on existing or expanded systems, and anticipated future growth impacts on support systems not only of the project but of other surrounding industry and urban devel-opment

Jan 1, 2008

The Gold Ridge Mine is an open-cut gold mine in the Solomon Islands. The mine is owned and operated by Gold Ridge Mining Limited, a wholly owned subsidiary of Ross Mining NL. At the invitation of the Solomon Island Government, project construction commenced in July 1997 and gold production commenced in August 1998. The mine is the countryÆs first, and represents a major milestone in the development of the Solomon Islands. At the time of project approval and construction, there was a growing awareness in the country of the potential impacts of mining in the tropics, partly due to unfavourable publicity surrounding a number of other mining operations in the Pacific region. The management of environmental impacts was therefore an important consideration in the approval of the project, and continues to receive a high level of attention from the Government and community. Ross Mining did not commit to the Gold Ridge Project until it had satisfied itself that all waste rock and tailings could be safely contained on-site, and that the standards normally expected of a mine in Australia could be met. Ross Mining approached the approval, construction, and operation of the Gold Ridge Mine with a set of operating principles that met Government and community concerns. These were:best practice environmental management; operation of the mine in accordance with standards expected of mining operations in Australia; independent peer review of key technical aspects; on-going consultation with Government and community; and equitable transfer of wealth to landowners and the local community. As a consequence, the Gold Ridge Mine has developed into a successful mining operation with a high level of support from local landowners, the general community and the Central and Provincial Governments of the Solomon Islands.

Jan 1, 1999

By R N. Humphries

The aim of this paper is to question the need to develop bespoke monitoring and assessment methodologies and criteria, thereby ‘reinventing the wheel’, when designing and assessing the success of important natural habitat and ecosystem restoration schemes at mine sites in the UK and Australia. It draws attention to the existence and applicability of the Phase I Habitat, National Vegetation Classification (NVC) and Condition Monitoring methods in the UK and similar approaches used in Australia. These are long accepted established methodologies and have published accounts for describing, assessing and managing natural vegetation communities, habitats and ecosystems. They are often used at the environmental impact stage, but seemingly rarely, if at all, in restoration design and management at mine closure. Their application to mine restoration and closure is illustrated and discussed by reference to a surface coalmine in South Wales, UK.It is concluded that the application of a combination of the Phase I Habitat, NVC and Condition Monitoring methods is highly relevant to the expectations of the Convention on Biological Diversity (CBD) and its implementation in the UK, and probably in Australia too. The methodology and criteria described could be incorporated into the guidance and specified in the mining permits so that there is clarity as to the expectations and requirements for monitoring and assessment for bond release. Their use could be of wider application where there is a requirement to assess the success of restored CBD assets and ecosystems.CITATION:Humphries, R N, 2014. Why reinvent the wheel when there are established methodologies to aid the design and assessment of restored natural ecosystems on mined land?, in Proceedings Life-of-Mine 2014 , pp 675–692 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Michael R. Norland

This U.S. Bureau of Mines report on U.S. and Canadian 1iterature pertaining to soil characterization and the use of soil amendments as a part of the reclamation process of coal surface-mined lands contains 1,280 references. The references were published during the 1977 to 1988 period. Each reference is evaluated by keywords, providing the reader with a means of rapidly sorting through the references to locate those articles with the coal mining region and subjects of interest. All references are annotated.

Jan 1, 1991

By Magdy Ibrahim

This paper presents experimental design and development of a low-cost remote sensing hardware designed to support automated site data acquisition for near real-time progress reporting of construction operations. The developed hardware utilizes open source microcontroller equipped with multiple sensors that include 3D accelerometer, GPS, Data logger and Bluetooth. The use of open source microcontroller makes the developed design cost effective; freeing it from the need for costly license fees. Its platform configuration is flexible; enabling the addition of temperature, weight and other sensors, Wi-Fi and Xbee capabilities to suit individual field applications. Pilot tests have been carried out in laboratory and outdoor environments. The results prove effectiveness and robustness of the developed configuration. The paper provides description of the individual components used in the development of this prototype hardware. It also describes the technical characteristics, capabilities and limitations of the developed hardware. The findings of comparison with alternative technologies used for outdoor tracking of construction operations are presented. The comparison is carried out with respect to range, cost and suitability for outdoor environment. The developed hardware is expected to support a wide range of applications including tracking of earthmoving operations, highway construction and onsite resources. As well, it is expected to enhance safety on construction jobsites.

Aug 1, 2013

By Louis R. Iverson

Patterns of species colonization, biochemical interaction among species, and competitive phenomena were studied in four reclaimed areas in western North Dakota ranging in age from one to four years after mining, along with a site from a native mixed grass prairie for comparison. Early successional changes in floristic composition and soil chemistry were quantified. The mined sites had been contoured, topsoiled, fertilized and seeded. Despite seeding of agronomic species, initial colonization was by fugitive species; analysis of the seed bank in topsoil showed that the most dominant colonizers immigrate after topsoiling. Of the 95 species encountered, Kuchia scoparia was the most dominant in the first two years following mining. Kochlo had relatively low densities in the first year (50-80 plants m-2), but was robust and attained heights of 88 cm with a biomass of about 400 g m-2 In the second year, the plant densities increased to over 10,000 plants m"2 but the height and biomass were reduced to 15 cm and 90 g m-2. However, during the third and fourth years Kochia density declined and was practically non-existent by the fourth year, while the planted Agropyron grasses had concomitantly increased. Other pioneers like Amaran thus retroflexus, Chenopodlum album, Helianthus annuus, Salsola spp. And Setaria spp. showed a less abrupt but similar decline. Chemical analysis of the soils over the same time period showed decreases in electrical conductivity (E.C.), and in the concentrations of P, Ca, Mg, Na, Li, Sr, and SO4 (due to leaching), while N increased. Field studies were conducted on the competitive relations between the dominant species - Kochia scoparia and Agropyron spp. - during early succession. It was found the Kochia acted as a "nurse" crop for several months during the first year of Agropyron spp. establishment, but then began to shade heavily by late July, thus reducing grass tillering. Field and growth chamber experiments on the intraspecific competition relations of Kochia demonstrated that its density and dry matter production, per plant and per unit area, conformed to several laws of plant population biology. Autotoxicity or the depression in growth of a species by its own degradation compounds, in Kochia, appears to be the main factor causing the decline in its growth. Results from a field experiment indicated that thinning dense second year Kochia stands to the density of first year stands did not alter the growth of Kochia, providing strong evidence for autotoxicity. Similarly, several growth chamber experiments demonstrated that small amounts of decaying Kochia leaves and especially roots were toxic to Kochia growth, but not Melilotus officinalis or Agropyron canlnum, Chemical analysis of the soils and plant tissues indicated nutritional im¬balances as shown by P/Mn and P/Zn ratios may be responsible for autotoxicity. In addition to Kochia, a bioassay experiment showed allelochemics to be important in several other colonizing species. Although our results indicate that later stage species generally have greater toxicities than first year colonizers, autotoxicity in the very initial stages seems to be accentuated by harsh habitat conditions. Several practices (mowing. fire, etc.) are used to manage grasslands. Mowing of the first year erect, annual, colonizing vegetation was shown to be beneficial in the growth and establishment of wheatgrasses after mining in western North Dakota. Plots containing Kochio predominantly were mowed in mid-and late-July, and in mid-August, during the first year of growth after recontouring, replacing topsoil. seeding and fertilizing. It was found the Kochia densities were reduced to two percent of the control and its biomass reduced to less than one-third when the area was mowed in mid-August. On the other hand, wheatgrasses showed increases of 23% in stem density and 860% in biomass production over the controls when mowed in mid-August. The mowing of Kochia just before seed-set apparently reduces interspecific competition between Kochia and Agropyron spp. during the following growing season. The method is highly recommended for use in hastening the establishment of planted grasses.

Jan 1, 1982

By Nadir Ansari, Brian W. Wilson, Marina S. W. Li

"A hybrid shoring system consisting of cast-in-place soldier piles with Cutter Soil Mixing (CSM) infill panels was constructed for temporary support of a 19.8 m (65 ft) deep excavation in Vancouver, British Columbia, Canada. Deep Mixing (DM) was completed up to 9.7 m (32 ft) in fill, peat, wood waste and clayey silt with embedment in dense till, and soldier piles constructed through the dense till extending to below final excavation level. Two trial CSM panels were installed ahead of production to assist with developing the termination criteria of the CSM panels in the dense till. The constructed depth of the CSM panels was based on interpretation of real-time monitoring data obtained through the Bauer B-tronic system. Inclinometer monitoring data from two CSM panels and two soldier piles, as well as soldier pile survey target data was used to assess and monitor the performance of the hybrid shoring system throughout bulk excavation. The objectives of this paper are to provide an overview of the design and construction aspects of the hybrid DM shoring system and to present inclinometer and pile target data to demonstrate the lateral performance of the CSM infill panels and soldier piles. This paper also discusses the merits of using real-time monitoring data as part of the engineering decision-making process for validating CSM panel construction. BACKGROUND A hybrid DM shoring design was recently completed for a high-rise development in downtown Vancouver, British Columbia for temporary support of a five level basement excavation. Deep mixing was proposed by the excavation and shoring design-build team as the preferred method to construct infill panels between soldier piles because of the speed at which the shoring system could be constructed in variable fill, peat, wood waste and overburden compared with traditional secant piling methods. The development site is generally a truncated triangle in plan, with the longest side of the triangle being approximately 115.7 m (380 ft) long and the two shorter sides being approximately 71.6 m (235 ft) (Hybrid Shoring Wall 1) to 75.0 m (246 ft) (Hybrid Shoring Wall 2) long. The site is bounded by an existing bridge off-ramp structure along its longest side, and by city streets on the other two sides, as shown in Figure 1. The truncated section is approximately 16.8 m (55 ft) (Hybrid Shoring Wall 3) long. Due to project constraints, the hybrid DM and soldier pile shoring system was only proposed for the two shorter sides of the triangle and the truncated section. Traditional secant piles were installed for the longest side. This paper focusses on the hybrid shoring system. A typical detail showing the CSM infill panel with the soldier piles is presented in Figure 2."

Jan 1, 2017

By L. P. Kleinmann

To control the formation of acid drainage at its source, the Bureau of Mines has investigated the role of iron-oxidizing bacteria in the oxidation of pyrite. In laboratory tests, it was determined that Thio-bacillus ferrooxidans could be controlled in coal refuse using anionic surfactants, with an associated decrease in acid production of about 75 pet. Based on these results, large-scale tests were conducted at an 8-acre active coal refuse area in northern West Virginia and an 11-acre inactive refuse pile in southern West Virginia. Acid production was decreased 60 to 95 pet for 4 to 5 months after application of 55 gal/ acre of 30-pct sodium lauryl sulfate solution. To date, effluent surfactant concentrations have been extremely low. Either a hydroseeder or a road-watering truck can be used to apply the surfactant. Since the surfactant solution must reach the pyritic material to be effective, sites that have been reclaimed are generally not amenable to these procedures. A simple laboratory test is described that provides an estimate of adsorption potential; this can be used to calculate a safe application rate.

Jan 1, 1983

By K T. Mandisodza, T J. Cartledge

The principal objective of Geotechnical Engineers supporting operating mines is to provide safe working conditions and ensure that pit designs are geotechnically optimised to site conditions and pre-defined stability requirements. Pit slope designs are delivered in advance of pit excavations. Making changes to these designs is usually slow to enact and involves a layered sign-off before implementation, leading to unwanted delays in their adoption and subsequently increased production pressures. When unexpected ground conditions are encountered during the mining process, or short-term mining schedule requirements demand it, changes to these designs may not be easily feasible in certain situations. It is when these scenarios arise that Geotechnical Engineers need to be proactive and consider unconventional options to deliver safe operating conditions while satisfying short-term requirements to the mine schedule. Essentially, the geotechnical short-term strategic designs double-pronged approach supports the mine schedule while providing safe conditions and minimising geotechnical risks for people and equipment. Common short-term strategic geotechnical designs include; slope buttressing, over-steepening cut slopes to increase reserve recovery through unplanned or emergency cutbacks, and accepting risk threat and operating under unstable slopes. When implementing strategic design options, the Geotechnical Engineer must consider the broader implications for such designs. They must think of the plan’s long-term effects on the mine schedule and pit wall stability. Initiating aggressive designs to recover additional reserves to satisfy a short-term scheduling demand could result in-pit wall instability or suboptimal pit layout. Before and during the implementation phase, the Geotechnical Engineer must communicate and engage with relevant stakeholders to ensure that the plan is executed accordingly and geotechnical risks are effectively managed. Proactiveness to ground response and implementation of risk management strategies will improve safety performance and optimise mining schedules.

Jun 22, 2022

By Mark Colwell, Russell Frith

This paper summarizes the results of a research project whose goal was to provide the Australian coal industry with a chain pillar design methodology readily usable by colliery staff. The project was primarily funded by the Australian Coal Association Research Program and further supported by several Australian longwall operations. The starting point or basis of the project was the Analysis of Longwall Pillar Stability (ALPS) methodology. ALPS was chosen because of its operational focus; it uses tailgate performance as the determining chain pillar design criterion rather than simply pillar stability. Furthermore, ALPS recognizes that several geotechnical and design factors, including (but not limited to) chain pillar stability, affect that performance. There are some geotechnical and mine layout differences between United States and Australian coal fields that required investigation and, therefore, calibration before the full benefits offered by the ALPS methodology could be realized in Australia. Ultimately, case history data were collected from 19 longwall mines representing approximately 60% of all Australian longwall operations. In addition, six monitoring sites incorporated an array of hydraulic stress cells to measure the change in vertical stress throughout the various phases of the longwall extraction cycle. The sites also incorporated extensometers to monitor roof and rib performance in response to the retreating longwallface. The study found strong relationships between the tailgate stability factor, the Coal Mine Roof Rating, and the installed level of primary support. The final outcome of the project is a chain pillar design methodology called Analysis of Longwall Tailgate Serviceability (ALTS). Guidelines for using ALTS are provided.

Jan 5, 1999

Raises are widely constructed underground in hard rock mining for ventilation, material transport or emergency escape. The four major raise excavation methods, Drop Raise, Conventional, Alimak and Raise Bore can be divided into two categories from ground control point of view, one ground support can be installed during excavation, the other not. Excavation method must be chosen carefully to keep the raise wall in stable state during excavation and make sure enough rock stand-up time to install ground support if needed. If rock quality is permitted and there is no strict space limitation, raise bore method which is the only method that ground support can not be installed after the whole excavation is finished should be considered first because it is faster, cheaper, safer and less disturbance to the hosting rock. Support may or may not be needed depends on the purpose of the raise and rock quality. In high quality hosting rocks, if the raise is only for ventilation or material transfer, support may be not needed. If it is for emergency escape or escape and ventilation, which provide or require personnel access, the whole raise must be supported either in high or low quality rock. Based on on site data collection, construction and raise utilization, this paper gave out the rule of thumb how to decide an excavation method. After purpose of the raise, required raise diameter (size) and raise site options being known, geotechnical data collection is the next important step in a raise project.

Jan 1, 2011

By S. Hon, C. Searcy, R. DasGupta, B. Fleet, A. Davidse, A. Pringle

"The mining industry is facing serious long- and short-term challenges relating to uncertain commodity prices, environmental pressures, and margin compression due to rising energy costs. Energy issues, formerly treated as an operating cost, are changing as executives search for longer term solutions to deal with uncertain fossil fuel prices and greenhouse gas emissions. Consequently, mining executives are increasingly willing to consider introducing a proportion of renewable energy (RE) systems into the mine energy mix. This paper examines how RE can be successfully integrated at mine sites, as well as some of the benefits and barriers to their wider adoption.RÉSUMÉ L’industrie minière fait face à de sérieux défis, à long et à court terme, en raison de l’incertitude des prix des matières premières, des pressions environnementales et des compressions de la marge bénéficiaire dues à la hausse des coûts de l’énergie. Les questions énergétiques, auparavant considérées comme un coût d’exploitation, changent alors que les cadres cherchent des solutions à plus long terme afin de prendre des mesures pour contrer les prix incertains des combustibles fossiles et les émissions des gaz à effet de serre. C’est pourquoi les cadres miniers sont de plus en plus disposés à considérer l’introduction d’une proportion de systèmes d’énergie renouvelable dans l’équation énergétique de la mine. Le présent article traite de la manière dont les énergies renouvelables peuvent être introduites avec succès aux sites miniers ainsi que quelques-uns des avantages et des barrières à leur application à une plus grande échelle."

Jan 1, 2015

By James J. Brady

The basic story at Bear Swamp was how to excavate an underground chamber 79 feet wide by 227 feet long and 150 feet high, along with the related access, tarbrace, leads, power tunnels and shafts, do it under cost and ahead of schedule and still have just about everybody love you. The isometric sketch of the overall project follows. I won't go into any of the details of the physical scope at this point. Instead, we'll bring out the sizes, grades, particular problems of the different areas as we cover them. First of all, let's establish that Bear Swamp was a Target Estimate - Fee with Incentives type of contract. Gates and Fox's contract was with the project's general contractor, J. A. Jones. We were one of three contractors who submitted proposals and estimates to Jones. After much negotiation and many submittals, Gates and Fox was notified we had been selected to do the underground excavation on April 12, 1971. We had our first people back on site in two days, set up a temporary office, made our first steel order for jumbo erection, pacing our jumbo construction to meet the date when J. A. Jones would have the access portal ready for us. The shops, yards, dry house, compressor building were all erected as sites were designated for our use. At last, on Thursday, June 3, we trimmed the face and moved our 9-machine Euclid jumbo up a hastily constructed haul road and started our portal preparation of the access tunnel.

Jan 1, 1974

By Donald K. Sparling, C. Edwin Baker

The White Mesa uranium/vanadium mill is six miles south of Blanding, UT, on the Colorado Plateau, which has historically spawned more than 200 uranium mines. As uranium prices approached an all-time high during the mill planning period, Energy Fuels Nuclear Inc. anticipated the reopening of many of these mines, whose low grade ore suddenly looked economic. The company located the White Mesa mill close to these mines, to minimize hauling distances to the mill and give vendors added incentive to reopen or expand mine operations. A receptive local community, a relatively unencumbered trip through the regulatory maze, and some mill circuit innovations all helped to make the White Mesa mill a well functioning reality. From a strategic standpoint, and to begin ore stockpiling as early as possible, Energy Fuels constructed two ore buying stations and began receiving ore in early 1977. The buying stations were located at Hanksville and at what is now the Blanding mill site. Ore receipts at Hanksville did not materialize as anticipated and the facility has since been closed. The Blanding ore buying station is now an integral part of the milling operation. All ores, whether company, vendor, or for toll milling, are received at the Blanding station. The Blanding site was central to the plateau mines, and was well received by area residents, who encouraged the introduction of industry to the area. Residents viewed mill construc¬tion as an economic blessing and were prepared to accept the associated im¬pacts. Energy Fuels hired as many local people as possible for mill opera¬tions.

Jan 4, 1981

By Alp Gokalp

The aim of this article is to present an application of jet grouting technique in stiff clays for foundations of the natural gas combined cycle power plant, under construction in Aliaga, Turkey. The plant site is in the Aegean coastal region and 60 km north of Izmir. The foundation soil is composed of quaternary alluviums on top and tuff base rock. The thickness of the alluvium varies between 16 m to 30 m. Groundwater was observed 2.5 m below the ground level. At the design stage, settlement analyses were carried out for the various buildings and facilities in the power plant. Based on the analyses, it was predicted that total and differential settlements are not tolerable, thus jet grouting is implemented as a ground improvement under the majority of the foundations of the power plant. This paper also describes the selection of jet grouting technique, application type and details of the process parameters such as injection pressure, number and size of nozzles, lifting and rotation speeds. Prior to the commencement of the jet grouting works, a number of preliminary parameter tests and preliminary pull-out tests were carried out throughout the site in order to define and verify the jet grouting process parameters to achieve the required diameter of 600 mm and minimum jet grout strength of 3.2 MPa. Moreover as part of the comprehensive quality control and quality assurance program pursued in the project, a number of tests; such as continuous coring, integrity testing, installation of confirmatory jet grout columns, were carried out during the production of jet grout columns.

Jan 1, 2002

By W. Fourney

In the late 70’s and early 80’s in conjunction with other oil and gas well stimulation studies, personnel from the Dynamic Effects Lab performed model testing to demonstrate the effectiveness of utilizing an open section of borehole just before a plug. We called the process stem induced fracturing. The open section beneath the stem was used to increase the pressure magnitude and spread out the duration of the pressure pulse. This technique was later utilized to by Frank Chiapetta (1) in the fracture and fragmentation of rock in quarry blasting situations. He called his technique air deck blasting. In fact, Frank found that the Russians had previously discovered the same technique. There is currently interest in utilizing air deck blasting with an open section of hole beneath the explosive at the bottom of the bore hole to better remove the toe in a fragmentation shot. This paper reviews the development of stem induced fracturing and then describes a series of model tests conducted to measure borehole pressure at points along a borehole when an explosive charge is detonated at the midpoint of the borehole. Tests were conducted in both stiff boreholes (aluminum) and less rigid boreholes (PMMA-Plexiglas). Pressure time profiles were measured at the charge site, midway between the charge and the bottom of the hole, at the stemming at the top of the borehole, and at the bottom of the borehole. Crack initiation sites and crack propagation were also determined in the PMMA models. Some high speed pictures were taken of the event in the PMMA.

Jan 1, 2006

By Lee Trudick

The secondary dispersion of copper, zinc and fluorine in A horizon soils was examined in Pope and Hardin Counties, IL, by sampling 122 sites along five traverses. Four of the traverses were taken above a deeply buried manto; a fifth intersected a vein complex exposed at the bedrock surface. Plants at each site were examined and analyzed for fluorine and on one traverse for copper and zinc. The A horizon soils were also tested for lead, manganese, barium, nickel and cobalt. The total content of copper, zinc, and other heavy metals in soils was determined by atomic absorption spectrometry (AAS) after acid bomb dissolution. Fluorine in soils was determined by fluoride ion-specific electrode after fusion with NaOH. Several cold- leach methods were also used. The analysis of A horizon soils for copper and zinc by AAS after acid bomb dissolution is a promising geochemical tool in the search for fluorspar. The acid bomb dissolution method is simple and takes little laboratoy time; it Produces a total dissolution of the sample with relatively little loss of the elements, and 20 elements can be analyzed from the same sample. In this study, the highest copper values were 80 times the local background level of 25 ppm and anomalies of this element tended to outline the fluorspar orebody better than either zinc or fluorine. The greatest zinc value was 15 times the local background level of 100 ppm, while the highest fluorine values were approximately four times the local background level of 165ppm.

Jan 1, 1982

By E. Koufetzis

Rock mass classification systems are core elements of tunneling and empirical mine design worldwide. The Bauxite division of S&B Industrial Minerals S.A. decided to implement a rock mass classification system in order to provide mining engineers and supervisors of the underground mines, with guidelines of stability performance and with a complementary tool for the selection of the appropriate tunnel support. The back analysis system employed is based on visual observation of especially selected underground mine sites, representative of all rock types. This fact combined with the failure or success of the already existing support system, constitute the fundamental part of the work undertaken. The paper is divided into three main parts. In the first part the classification methods of Q, RMR89 and GSI are presented and the advantages and disadvantages of each method in connection with underground mining are indicated. RMR89 and GSI are conclusively selected for use, the main criteria for the selection being, the simplicity in use and the competency of the support system suggested for each rock mass category. The second part points out the methodology for measurements, the practical difficulties encountered during this process and the guiding principles followed, in order to avoid these problems. In the third part, the final conclusion of this project is demonstrated and the different rock mass categories are presented with their relative support recommendations, as they were applied and tested in all phases of the bauxite mines? exploitation. The generated methodology is being implemented by the site mining engineers, for validation and potential improvement.

Jan 1, 2008

By Kazuyo Yokoyama

New environmental assessment model based on the Waste Input-Output analysis has been developed and applied for the "Landfill mining activity". "Landfill mining" implies the digging up of the landfilled wastes, the recovery of valuable material and energy resources and, thus, the reuse of the saved space as a new landfill site. In this study, the landfilled wastes are assumed to be treated by the gasification/melting processes. Two kinds of reactors, the fluidized bed type (FB) and the shaft furnace type (SF), have been considered in this work as the typical gasification/melting processes adopted in Japan. In FB, the dug-up wastes are heated in the sand fluidized bed zone under reducing atmosphere, Fe and Al are recovered in the metallic form, and then, the gasification/melting of residues is made in the second zone. In SF, the waste is charged in the high temperature coke bed, and the gas is recovered together with molten metal and slag. Both processes generate electric power by the recovered heat and fly ash as waste to landfill. It has been found in this study that the both processes can reduce the total volume of waste and save the available landfill space. SF seems to have higher potential for decreasing volume of wastes because of less emission than FB while FB has great benefit to recover metallic Fe and Al individually. The results of scenario analysis have also indicated that the landfill mining activity is effective for sustainable management of landfill sites.

Jan 1, 2006