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By Cherie H. Tilley

The possibility of drilling oil wells from underground locations is not a new concept. It bas not been cost effective for the oil industry in the past and therefore disregarded. Today's state of the art in tunneling and shaft sinking greatly improves the potential for this type of oil field development scheme. This report presents a plan for providing a aeries of drilling bases and the design of the drilling location. The design minimizes the amount of excavation needed to develop the oil field and maximizes the use of rapid excavation techniques.

Jan 1, 1983

By R. W. Fedors, S. T. Green, R. A. Hart, D. B. Walter

Computational fluid dynamic (CFD) modeling of a potential nuclear waste repository drift may be an important tool to estimate moisture redistribution caused by natural convection within the drift. To refine and support CFD techniques, a small laboratory cold-trap experiment was developed. Results from numerical modeling of the laboratory experiment show the sensitivity of the bulk air flow rate and average air temperature within the drift to several key parameters, including various boundary condition assumptions and surrounding porous media properties.

Jan 1, 2004

By P. N. Saavedra, E. A. Salamanca

"The maintenance strategies in the mining industry are changing from operative and periodic inspection strategies to a condition-based, predictive maintenance strategy centred in vibration analysis plus complementary techniques. Condition monitoring can also help to improve availability by being able to pinpoint and diagnose problems on operating machinery at an early stage. This reduces unscheduled downtime and production losses.However, in mining, for shovels operating in transient modes, with variable load and/or speed, the FFT (Fast Fourier Transform) standard approach is not directly applicable for analysis. This work illustrates how spectral order analysis and new transforms, called time-frequency transforms (TFT), allow us to monitor the shovel when it is working. Some practical examples showing the application of these analysis techniques to occasional vibrations measured on hoist and crowd transmission of a shovel are also presented. It is shown that at present, it is possible to carry out the vibration monitoring in the mining shovel while it is working, therefore avoiding the high cost of a loss of production which can occurr in traditional monitoring, where the measurement is taken while the shovel is out of production."

Jan 1, 2002

By X. Cui, H. Ding, J. Wen, Q. Gu

This study is a continuation of previous work designed to further explore the mechanism of the bioleaching of sulfide concentrate at neutral pH by heterotrophic bacteria Bacillus megaterium QM B1551. The concentrate contained 13.2 percent nickel (Ni) and 0.2 percent cobalt (Co), which presented primarily as pentlandite and pyrrhotite. Contact and noncontact bioleaching experiments were conducted with finely ground ore at an initial pH of 6, resulting in 44.7 percent of Ni and 38.2 percent of Co leached in the contact-bioleaching treatment. Oxidation experiments of sulfur, thiosulfate (S2O32−) and ferrous ions (Fe2+) by cell membrane were performed to verify whether sulfur transferase, thiosulfate quinone reductase and enzyme cytochrome B558 on the surface of the bacteria could be expressed to oxidize the sulfide. The results show that thiosulfate quinone reductase and cytochrome B558 could be expressed to oxidize S2O32− and Fe2+ to SO42− and Fe3+, respectively.

By Larry A. Cramer

"Three primary drivers are setting the trend for base and precious metal processing . they are: continued low real base metal prices, environmental concerns, and continued high prices for PGM.s. Low base metal prices are increasing the search for economies of scale and company consolidation as well as the development of some hydrometallurgical technologies. Environmental concerns are pushing for continued reductions in SO2 emissions and hydrometallurgical technologies. The high prices for PGM.s are driving major expansions and a focus on minerals processing recoveries and, to a lesser extent, reductions in the refining metal lockup.In nickel, HPAL operations on laterites have failed economically but Inco is still pursuing some alternatives. BHP-Billiton and others are developing bioleaching alternatives for nickel laterites and sulphides.Copper continues to be dominated by the hydrometallurgical and pyrometallurgical debate; new hydrometallurgical developments are being tested at several sites whilst the pyrometallurgists continue to make competitive cost and environmental improvements.Gold processing developments are dominated by the use of improved gravity recovery equipment and by the development of thiosulphate as a more environmentally acceptable lixiviant.PGM processing trends are the use of fine grinding technologies, higher power input flotation cells, and new pyrometallurgical technologies. Hydrometallurgical options for some applications are being sought.OVERVIEW The metals industry has remained under price pressure for some time; low and decreasing real prices for most metals have become an expected scenario. Occasional price spikes give some relief but invariably bring expansions and new entrants into an already oversupplied commodity market, thus leading to the continued price pressure. Technical innovation, economies of scale, and improved work systems are continually sought, so as to improve the competitive position of each individual company in such a climate; however, these developments add to the downward price pressure. In such a situation the application of scarce funds to research and development is a difficult task. Excess funding is not available in tight economic times and yet the main route to higher profits is clearly the application of technical developments to lower the cost of producing a metal commodity. Many technical centers have closed as a cost saving exercise and some have coalesced to obtain economies of scale. The Australian based AMIRA research organisation has grown to serve the R&D part of the market well in Australia and in South Africa by acting as the catalyst to form research partnerships between a number of industry players and as an administrator to direct the funding of research projects towards the various applicable research institutions. AMIRA has developed closer ties to Camiro (Canadian Mining Research Organisation) through the appointment of Camiro.s metallurgical processing research director as AMIRA.s North American based director. AMIRA is continuing discussions with MIRO (Minerals Industry Research Organisation) in regard to a merger, with a report outlining the merger proposal expected in March of 2003. Company focused research centers continue to be effective at Anglo American Research Labs, Teck-Cominco Research, Falconbridge Research center, Inco Research and some others."

Jan 1, 2003

By J. W. Thompson

RAILROAD GRANT-MDIERALS. Diatomaceous or infusorial earth when found in such quantity and quality as to render lands containing deposits valuable therefor are mineral lands within the meaning of the mining laws and must be excepted from grants to the Central Pacific Railway Company. Central Pacific Ry. Co., In re, 45 Land Decisions, 223, p. 226. RAILROAD GRANT-CLASSIFICATION, If any evidence of minerals is found upon lands within a railroad grant and the showing is sufficient in the opinion of prudent and qualified persons to warrant further exploration and expenditure, with reasonable prospects of success, then the land can not be classified as nonmineral and is not subject to the grant to a railroad company. But where there is no present indication of minerals nor any geological evidence upon which to base a mineral finding, land should not be classified as mineral, or held for further classification and reserved from the railroad's grant, upon the surmise that future prospects might disclose evidences of minerals. Southern PacUl.c Ry. Co., In re, 45 Land Decisions, 326, p. 329. INDEMNITY SELECTION BY RAILWAY COMPANY, Under section 3 of the act of July 2, 1864 (13 Stat., 365), and the joint resolution of May 31, 1870 (16 Stat., 378), the Northern Pacific Railway Company could take coal and iron land within its primary or grant limits. It could not base an indemnity selection upon the claim that certain land was coal or iron in ;;haracter, as such land was not lost to it as part of the grant. But the company was authorized to select other lands in lieu of those lost because of their mineral character, but the word "mineral" did not include iron or coal, and, accordingly, the railroad company was entitled to take coal lands under its indemnity selection.

Jan 1, 1917

By Mehmet Guney

At the Armatcuk mine in Turkey, various modifications of sublevel methods have been tried during the last decade in an effort to eliminate gob fires, dangers from roof falls, and surface subsidence, and also to increase extraction efficiency. From the experience thus gained, it was decided that the most likely system to give maximum benefits, considering the existing geological conditions and coa1-seam characteristics, was hydraulic stowing. This paper examines trends in the working techniques of hydraulic stowing and discusses the favorable results and technical problems that the method produced at Armutcuk. The Armutcuk mine, a subsidiary of Eregli Coal Mines (EKI), produces 1300 tons of run-of-mine coal daily from thick (about 10-90 ft) and highly dipping (about 50-90°) coal seams. The coal is highly volatile with good coking properties that make it highly suitable for industrial use. Most of this coal is used in the iron and steel industry at Eregli on the Black Sea coast. Complete recovery of the coal is of vital importance to industrial development and progress. Initial coal extraction was carried out by means of a sublevel mining system modified to accommodate local geological conditions and coal seam characteristics. This method is similar to that employed in metalliferous mines. Several problems arose from the application of the method, one of them being the prevalence of gob fires which caused periodic shutdowns in some sections. To achieve maximum coal extraction with minimum dilution, to eliminate gob fires and surface subsidence, and to reduce fatal accident rates, a decision was taken to change from this method to a hydraulic stowing system. The pres- ence of large deposits of conglomerate and sandstone on the surface contributed to the decision to employ this new method. Although hydraulic stowing practices have been carried out in America and Germany, Upper Silesia may, so far as coal is concerned, be considered the birthplace of the method. Here the process was adapted to thick coal seams on a large scale to reduce dangers from gob fires and damage from surface subsidence. Today, the mining system is not only widely used in the coal mines of France, the Saar, India and Poland, but has also been successfully applied to the iron ore and potassium salt mines in Russia and Germany. LOCATION AND HISTORY The Kandilli-Armutcuk coal field, the most western outcrop of the North Anatolian coal basin, extends for five miles along the Black Sea coast (Fig. 1). The Armutcuk Mine is situated on the southern boundary of the coal field about 40 miles from Zonguldak and about 12 miles from Eregli. The history of coal mining in the North Anatolian coal basin goes back more than a century. Mining commenced on a small scale in the Kandilli-Armutcuk coal field in the late 1880's, and from this time until nationalization in 1940 the mines were operated by private Turkish and foreign interests. In 1940, Eregli Coal Mines was established to takeover the management of these enterprises. The Armutcuk Mine was developed for the first time in the mid-1940's. Since then it has been in continuous production and it now produces an annual 440,000-ton run-of-mine output from which 320.000 tons of salable coal is obtained. MINE GEOLOGY The carboniferous inlier of the Kandilli-Armutcuk coal field crops out over an area about three miles long and one mile wide. The major part of the inlier consists of the Namurian formation with only a relatively small area of Westfalian-A visible on the surface (Fig. 2). The Namurian formation, which has no exploitable coal seams in the Armutcuk Mine, consists mostly of arkose sandstones and black shales often having

Jan 1, 1969

By Paul R. Thomas

The Bureau of Mines evaluated the impact of the depletion allowance upon the economic availability of copper from domestic deposits. The potential long-run percentage depletion deduction, cumulated over the life of the properties, was estimated at approximately $2.5 billion for producing properties and up to $11.7 billion for nonproducers. The income transfer, in the form of higher Federal income tax payments if the allowance were repealed, was estimated at $1.5 billion for producing properties and up to $8 billion for nonproducers. The percentage depletion allowance, through its role in determining Federal income tax liability, was found to be very significant in affecting profitability. Repeal of the allowance could result in major domestic copper availability reductions at all price levels, now and in the future, as a result of reduced profit margins for current producers, and postponement of development decisions for nonproducers. It was demonstrated that a 50-percent reduction in the percentage depletion rate applicable to copper would also result in a significant decrease in profitability for nonproducing properties. For producing properties, the percentage depletion rate on copper was shown to be less significant than the income limitation that is placed upon the total amount of the depletion deduction. Repeal of the minimum Federal tax provision was shown to be significant in enhancing profitability for both producing and nonproducing deposits. The report concludes that the percentage depletion allowance operates as an important method of capital recovery and production incentive.

Jan 1, 1982

By Patrice Favreau

In 1990 the Noranda Technology Centre commenced a project to develop an interactive three-dimensional blast design system using a commerical computer-aided drafting and design package (CADD). The objective was to alleviate the blast engineer from the tedious and time consuming blast layout and design functions normally done by hand. This would allow more time for optimizing blast designs through assessing multiple options. Since several blast design software "tools" already existed at Noranda, the need arose to integrate all the applications into one overall system that shared one common database. The result is BLASTCAD.

Jan 1, 1992

By Carl Bertrand, Patrice Nadeau, Claude Bazin

"Rio Tinto Fer et Titane processes the ore extracted from the Lac Tio orebody to concentrate the hemo-ilmenite (FeO.TiO2-Fe2O3) mineral that is subsequently smelted to produce pig iron and titanium oxide slag. The ore is crushed, heat treated (roasted) and concentrated using dry magnetic separators. This paper describes a model to predict the magnetic susceptibility of the roasted ore and its behaviour in the magnetic separation plant. The model uses a classification of the ore as a function of the size and magnetic susceptibility of the particles. A subsequent division into mineral species allows the simulation of the magnetic separation process. The model is used to assess various operating options when process disturbances occur.INTRODUCTIONOre processing operations consist of ore size reduction followed by the recovery of valuable species in a concentrate that is subsequently sold for its minerals or metal content. The concentration processes are based on the physical and/or chemical properties of the minerals contained in the ore. Flotation is typically used to recover minerals of base metals such as copper, zinc, lead or nickel. Iron ore and other dense minerals are typically concentrated by gravity separation processes. Magnetic separation uses the magnetic properties of the minerals to concentrate magnetite and other minerals, to clean coal concentrate and to recycle ferrosilicon for dense separation processes (Brophy, 1985).Magnetic separators can be divided into low and high intensity separators and high gradient magnetic separators (Gillet, 2008). Most of the low gradient magnetic separators are built as rotary drums that are operated in wet or dry conditions. Dry magnetic drum separators are used by Rio Tinto Fer et Titane in Sorel-Tracy, Canada to concentrate hemo-ilmenite from the ore extracted at the Lac Tio Lake mine near Havre St-Pierre, Canada. The analysis of production data suggests that process improvement could be achieved by identifying key variables for the control of the magnetic separation circuit and/or by modification to the circuit flowsheet. The use of a process model was considered to be an effective approach to conduct a preliminary analysis of the circuit with a view toward process optimization. However, the literature contains few detailed studies dealing with the modelling of magnetic separation processes."

Jan 1, 2011

By James R. Wickens, David La Rosa, Robert E. McIvor, Adrian Dance

"The comminution circuit at Barrick Cortez Gold Mine uses an open circuit primary jaw crusher followed by a standard SABC grinding circuit. The grinding circuit incorporates a 26’Ø x 11’ SAG mill, an Omnicone 1560 pebble crusher and a 16’Ø x 28½’ ball mill. Both mills are driven by 4500 HP motors.In 2007, several comminution circuit studies were performed to assess circuit performance and map a course for improvement. This paper discusses the results of those studies including an analysis of mine-to-mill opportunities, grinding work index efficiency, and ball mill functional performance. Subsequently, improvements to the circuit were made to enhance operating efficiency. Specifically, improvements to the pebble crusher liner configuration, advanced process control system (expert system) and ball mill classification and ball charge are discussed. In addition, other current and future improvement opportunities are discussed.INTRODUCTIONThe Barrick Cortez property is expanding to include the new Cortez Hills open pit and underground mines. Ore from these new mines will be processed in the existing Pipeline mill facility. In conjunction with ore characterization work, performance of the comminution circuit needed to be quantified. Thus, in 2007, the comminution circuit was surveyed and opportunities for improvement identified.Figure 1 below shows the Pipeline mill flowsheet. It is a standard SABC grinding circuit using an open circuit primary jaw crusher followed by a 26’Ø x 11’ (7.92m Ø x 3.35m) SAG mill, in closed circuit with a Omnicone 1,560 pebble crusher, and a 16’Ø x 28½’ (4.88m Ø x 8.69m) ball mill. Both mills are driven by 4,500 HP (3,357 kW) motors. The SAG discharge screen aperture is 5/16” (8 mm) x 1-1/16” (27 mm) slots. Ball mill circuit classification is done with Krebs D20B cyclones."

Jan 1, 2009

By William D. Hissem

For those blasthole applications which require the use of holes ranging from 1” to 5.5” in diameter, the use of top hammer drills has been the equipment of choice for several generations of drillers. Pneumatic compressed air and hydraulic compressed oil systems represent the primary technologies which are available to the drilling practitioner. While both employ the same operating principals, the characteristics of performance, cost, and reliability can be markedly different between technologies and manufacturers.

Jan 1, 1998

By M. Jayaraman

With the ever increasing demand for commodities, due to changes in lifestyle and increase in population, people are striving to find ways to keep up. Mining is one essential element in the solution. Though being a powerful boost to a country?s economy, mining can have disastrous effects in the absence of waste management practice and technologies; because of the harmful heavy metals and toxic chemical waste that is generated as a by-product in mining operations. It is an established and documented fact that pollution is a major concern for communities having to live with it. Disproportionate water consumption significantly impacts local rivers and ponds thereby reducing freshwater availability and have given rise to social conflict. In light of these misgivings, management and treatment of mine water and waste has gained considerable attention recently. In this paper, we summarize some of the treatment methods that can be adopted by mining companies to reduce their environmental footprint. Appropriate treatment solutions depend on various factors including available space and capital cost for treatment solutions, type of mining waste generated, current state of the mining plant, geographical location, and other location specific issues. Incorporating waste and water management solutions as a priority within mining operations is critical for addressing increasing regulatory requirements and a starting point for initiating other Corporate Social Responsibility (CSR) programs. Collaboration among mining companies, NGOs, local community, and government facilitates successful projects which build trust leading to long term relationships. In this paper we also talk about the benefits of implementing a CSR project that captures the focus of local communities and allows the mining company to focus on operations. Implementing a sustainable business model that incorporates the broader community impacted by projects will continue to benefit even after the mining company ceases operation in that location. The challenges involved with implementing effective CSR projects, which require measuring and reporting effectiveness to create a positive social, economic, and environmental impact is also presented in this paper.

Aug 1, 2013

By Arthur M. Langer

Since the promulgation of the first Federal Asbestos Standard by the Occupational Safety and Health Administration in 1972, other federal agencies have modified the standard to better carry on their own unique missions. The instruments used to identify and measure asbestos, the sampling protocol, and the criteria used to define asbestos, have been modified to some degree. The Mine Safety and Health Administration regulates and controls asbestos dust in the mining and mineral commodity industries. However, crushed stone and processed ores contain mineral fragments that are frequently difficult to distinguish from asbestos. Mineral nomenclature, instruments for particle analysis, and sampling strategy must be accommodated to some degree to make asbestos control workable and meaningful. Precedent in other agencies has made consideration of these changes possible. Newly identified amphibole asbestos minerals have further complicated the agency?s regulatory charge. Changes in its Asbestos Standard are now being considered. Crushed taconite ore in the Eastern Mesabi highlights many of these issues. ©2008 Published by Elsevier Inc. Keywords: Amosite; Grunerite asbestos; Crocidolite; Riebeckite asbestos; Tremolite asbestos; Actinolite asbestos; Winchite asbestos; Richterite asbestos; Arfvedsonite asbestos; Fluor-edenite asbestos; Asbestos defects; Cleavage fragment; Mineral habit; Mesabi amphiboles

Jan 1, 2008

By Paul C. Schmall, Arthur B. Corwin, Derek Maishman

Ground freezing occupies a unique and important niche in underground construction, fulfilling a geotechnical need that is difficult, or sometimes impossible, to fulfill through other groundwater control and excavation support methods. Where complete groundwater cut-off and in-built ground support are required, and deep excavation is planned or the work occurs in difficult or disturbed ground, ground freezing offers the assurance critical to safe and timely construction. Compared with other groundwater cut-off or excavation support methods, a frozen wall is easily connected to underlying bedrock and will also adhere to adjoining subsurface installations or obstructions, if necessary, to provide a composite cutoff structure. Ground freezing is effective in all soil and ground conditions and has been used for emergency situations in disturbed, displaced or loose ground, where detailed soil characterization could not practically be performed.

Jan 1, 2005

Mineral Resource Throughput Management is based on the extraction of the maximum potential value from an ore reserve with the emphasis to generate maximum ROI and ROR (return on reserve). A steel producing company in India implemented MRTM to significantly improve their ROI and ROR. The value chain of this company consists of their own iron ore and coal mines, ore washing plants, sinter plants, steel plants, and sales and marketing division. The target for the mines was to produce at a stable and predictable rate and at specific quality requirements. These requirements were set to improve productivity and ROI of the steel plant. The implementation constituted the alignment of the reserve potential, total production chain, human resources and management culture at the mines with the requirements of the steel plant. Many typical mining practices were challenged and changed. Production targets regarding lump vs. fines ratio, consistent product tons, quality targets such as Fe, Al content and moist, and standard deviation on the quality targets were not achieved. A reverse distribution model with release mechanisms to satisfy the demand were developed and implemented at the mines. A stable and predictable flow of mine product with quality standards well within the required standard deviation targets were achieved. The contribution from the mines to significantly improve the Net Profit, ROI and ROR of the company were reached.

Jan 1, 2007

By D. Settles, R. Rose, P. L. Dunn

"A new mineral sands operation is being developed in Georgia by Southern Ionics, Inc. (SII). Prevailing mineralogy and certain design constraints required detailed testing and circuit analysis to create a robust separation processes. The floating wet concentrator plant (WCP) and mineral separation plant (MSP) flow sheets were designed based on historical testing information and recent SII test campaigns on various composite feed samples. The flow sheets were finalized through rigorous process and orebody sequence modeling.The process uses traditional physical separation equipment; however a new MT spiral, the MG12, was selected for use on board the WCP for roughing duty. The MG12 spiral is a two-stage, twelve-turn spiral that has been proven to achieve very high recoveries of heavy minerals. The floating plant includes feed desliming operations, a central MT surge bin for optimum spiral circuit feed control and ancillary operations for concentrate and tailings handling. Scrubbed heavy mineral concentrate (HMC) is then transported to the MSP for concentration of the titanium and zirconium bearing mineral fractions.The testing, flowsheet development, and plant design will be described and explained, and a brief summary of the current project status will be given.IntroductionSouthern Ionics Inc. (SII) is a privately held chemical manufacturing company, founded in 1980 by Milton Sundbeck. SII focuses primarily on the sale of specialty and intermediate inorganic chemicals. Core markets include cement and refinery catalysts, molecular sieves, zeolites, pulp and paper, pharmaceuticals, TiO2 and water treatment. SII is built on the four cornerstones of service, quality, technology and delivery with all SII facilities ISO certified and key products used in potable water treatment certified to NSF standards. SII owns and operates its own transportation fleet and is focused on being a low cost producer, committed to safety and the environment."

Jan 1, 2015

By Robert L. Davidoff

Growing domestic and global demands for mineral resources have established an imperative need for developing comprehensive, versatile mineral supply analysis evaluation tools. The Minerals Availability System (MAS) of the Bureau of Mines is meeting this need with its computerized Supply Analysis Model (SAM). This paper describes the SAM system and the quantitative methods used by the MAS for mineral supply analyses. The MAS evaluating process consists of deposit identification, tonnage and grade determinations, engineering and cost evaluations, financial analyses, and supply curve generation. MAS has developed this computerized system primarily to facilitate the maintenance of data information for the constructing of commodity supply curves. The SAM system presently has the analytical capabilities of simultaneously (I) evaluating many mineral deposits, (2) updating mineral supply information to reflect inflationary changes in costs and prices, and (3) conducting sensitivity analysis to determine impacts on mineral supply under various conditions. Many potential users in both government and industry will find the SAM system a valuable tool for policy analysis, forecasting, and planning. The SAM system has been constructed so that any types of information that are similar to the data elements in the MAS data base may be used to perform supply studies. The storage space needed for the SAM system?s programs, files, and output data is approximately 14 million characters.

Jan 1, 1980

By Michael Mann, Kenneth K. Eltschlager

The International Society of Explosives Engineers (ISEE) Standards Committee has recently updated both the Field Practice Guidelines for Blasting Seismographs and the Performance Specifications for Blasting Seismographs. The revisions are the result of public and industry input along with recommendations of the ISEE Blast Vibration and Seismograph Section. The committee is comprised of blasting seismograph manufacturers, users and general interest personnel. On an as needed basis, subject matter experts are enlisted to advise the committee. Three phases of activities are necessary for each revision cycle: request for comment on the existing standard, first draft revision of the standard based on public input, and final draft approval by the ISEE Board of Directors. The ISEE standards revision process will be explained and each standard will be discussed along with the significant revisions from the latest revision cycle.

Jan 1, 2018

By James McKelvey, Larry Drolet, Jason Swartz

INTRODUCTION When divers discovered that sections of a tunnel housing the pipeline that conveys wastewater from the Charleston Peninsula to the Plum Island Wastewater Treatment Facility had caved in, the Charleston Commissioners of Public Works(CPW) moved quickly to determine a long term solution for the city’s collection system, immediately focusing on the Ashley River sewer tunnel along the western boundary of the peninsula. Working with the Charleston community, as well as federal, state, and local officials, CPW developed a fast track yet long life design that can be used as a model for underground construction of tunnels in urban areas. The paper that follows summarizes key aspects of the Ashley River sewer tunnel project. HISTORICAL CHARLESTON Charleston, South Carolina is a culturally significant and historic city that was originally settled in 1670. There are over 100 buildings on the National Register of Historic Places within the Charleston area. Additionally, the first shots of the American Civil War were fired at Fort Sumter in the Charleston Harbor in 1861. As one can imagine, tourism generates significant business for the area with over 1.5 million people visiting Charleston each year. No project, especially one that requires digging, is done within the old city on the Charleston peninsula without careful planning. Many precautions are necessary to prevent damage or disruption to the historical properties. The Ashley River sewer tunnel project is exclusively in the old city. A lot of work was done during the design phase to minimize the impact to historical properties. Some of this work included: an archeological study (where pre-digs were monitored at all shaft sites by an archeologist); a building/structure assessment study (where structures near a shaft site were completely surveyed and cataloged); and an environmental study.

Jan 1, 2005