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By B. A. Comley

Over the past few decades a great deal of effort has gone into characterizing the effects of frother type and concentration in flotation using a variety of two-phase techniques. Whilst useful and informative, this research still does not assist in the selection of suitable frothers for three-phase industrial-scale froths. This paper investigates the effects of frother type and concentration in a three-phase industrial froth. The objective was to determine if progress could be made in terms of understanding the behavior of frothers in flotation and understanding how they affect the sub-processes occurring in the pulp and froth phases and, ultimately, the metallurgical performance of a flotation cell.

Jan 1, 2007

By G. V. Campbell, O. T. Holdsworth, M. G. Nelson

A senior design project is required by all accredited mining engineering degree programs. Often referred to as the capstone of a student’s education, this project is expected to include all the important components of the preliminary economic assessment of a mineral prospect, including orebody modeling, grade and reserve estimation, selection of mining and processing methods, preliminary mine design, access and utilities, environmental compliance and reclamation, and financial analysis. Two of the authors (Campbell and Holdsworth) completed a senior project in 2021. They analyzed the Akie zinc deposit located in Canada. This paper summarizes the economic analysis portion of that project. The two primary objectives of this economic analysis were risk reduction and integration of economics and engineering. Addressing risk is important as risk is one of the primary concerns in mining investments. Risk reduction was the primary concern through the entirety of this economic analysis. Integration of financial analysis and engineering design was the first component of a risk reduction design. This allowed for financial and engineering design to be optimized in conjunction with one another. This produced benefits from both a financial and an engineering prospective. From a market, economic, and financial risk perspective, risk was reduced by forecasting multiple metal price scenarios, and then addressing the Akie project’s economic viability at each price point. Lastly, risk was address through consideration of nontraditional financing options. The project also sought to minimize financial and human capital risk, by proposing mutually beneficial cooperative social relationships and favorable work, schedules. Description of that work is not included in this paper.

Mar 2, 2022

By M. Leslar

Slope monitoring has been an important issue in static terrestrial lidar for some time. Several solutions for monitoring the progress of a slide have been devised over the years. All of these solutions have required users to be in the field operating the lidar equipment. This paper presents a new system developed using the Optech ILRIS-HD or ILRIS-LR lidar and the scripting language of PolyWorks to produce an autonomous slope monitoring system. This system has proven invaluable in detecting and alerting mine workers to potential danger within their mine sites. It has already been deployed in two mine sites and is scheduled to be installed at a third.

Feb 27, 2013

global mining boom and in-creased demand for iron ore has lead to a resurgence in the mining industry in Minnesota. At the combined 81st Annual Minnesota Section of SME Meeting and 69th Annual University of Minnesota Mining Symposium, April 15-16 in Duluth, MN, this resurgence was the hot topic as new mining projects were featured in the keynote session. The meeting attracted more than 400 mining industry professionals, including engineers, executives, mining managers and suppliers from around the world. This year?s theme was ?New Ventures in Mining.? The meeting included concurrent technical papers sessions, a keynote session that featured three distinguished speakers and a panel discussion that provided updates on new mining developments in the state. The Minnesota Section of SME technical papers were presented in concurrent sessions, one on mining and one on mineral processing. The mining session included papers on drilling, ore blending, slope stabilization, dust control and operations management. The mineral processing session included papers on plant-control technology, ball mills, pellet strength and fans. Also offered was an SME short course titled ?Simulation based pellet induration optimization.? The Minnesota Section of SME held its annual business meeting during the conference. The 69th Annual University of Minnesota Mining Symposium technical sessions were held on April 15 and also consisted of concurrent sessions on mining and mineral processing. Mining session topics included logistics management, real-time performance measurement, uses for taconite aggregate and environmental issues. The mineral processing session included papers on ore liberation characteristics, zeta potential studies, induration modeling, fuel optimization and conveyor belts. The combined conference included a tradeshow with more than 80 booth spaces featuring vendors offering products and services to Minnesota?s booming mining industry. More than 900 people, including conference registrants and special invited guests of the vendors, at-tended the tradeshow opening reception. This was the largest trade show in many years ? an indication of the vitality of the mining industry in Minnesota.

Jan 1, 2008

What is the preferred electrolytic cell design and why? Hall: Considerable research remains to be done on electrolytic cell design. Studies are presently being conducted to determine optimum voltage and amperage. Zadra cells, which were used in some of the first carbon plants, are efficient when properly installed. Gold and silver are deposited on large-capacity, cylindrical steel wool cathodes. At times high value sludge falls from the cathode to the bottom of the cell. Rectangular cells, which were developed at some smaller operations in Nevada, require less floor space and have some desirable features in that cathodes can be moved and sludge can be removed from cell bottoms without actually shutting down the circuit. In South Africa two types of cells using graphite and diaphragm configurations are being tested. Duncan: The rectangular cell has one problem it's easy for shortcircuiting to occur. If you don't have a good seal on the side of the tank and on the bottom, the solution is going to want to flow around the bottom and sides of the cathodes and you're going to get poor performance in the cell. That is the advantage the Zadra cell has over the rectangular cell. With good sealing, which is a must, you should be able to get a ratio of the value of the solution going in to the value of the solution coming out of 10 to 1. Ken, can you tell me what you're attaining on the Zadra? Hall: At the Homestake gold operation in Lead, the cathode in the No. 1 electrowinning cell is loaded to about 600 ounces when it is moved to the refinery. At this time the No. 2 cathode is moved to the No. 1 cell. The No. 3 cathode is moved to the No. 2 cell and a cathode with new steel wool is placed in the No. 3 cell. In rectangular cells this sometimes is not possible because the loading on the cathode in the last cell may be as high as that in the No. 1 cell. As Don has pointed out this can probably be prevented by good seal design between cathodes. Potter: At the risk of sounding as though I'm straddling the fence, I really believe that either the round cell, as developed by Jack Zadra, or the rectangular cell will do an acceptable job. The Zadra is a fine unit. Leaks are not unknown but there are not very many. However, the rectangular cell is very saving of floor space. Plastics have been greatly improved during the past year or two and there is a very efficient design for the rectangular cell. It would have six cathodes in it and contain about 25 ft of steel wool. The body of this rectangular cell would be reinforced fiberglass plastic but with an integral lining of a high temperature plastic. I think either cell is so efficient and reliable that I would almost be tempted to flip a coin depending on floor space requirements. Either cell can be used to pull a loaded cathode and to advance the lesser loaded cathodes. Don, what is the configuration of your cell? Duncan: The Pinson rectangular cell has dimensions 2 ft wide, 30 in deep, and 10 ft long-long enough to take a dozen cathodes and anodes. We are currently using six of each but are not up to full capacity as yet. It's a steel tank coated with rubber. We have copper bus bars, which brings to mind that the last cathode in the tank, in one instance, was loaded heavier than the first one. That was probably a function of poor contact between cathodes and the bus bar. You can have erosion of the bus bar and if you don't get current flowing into the anode and out of the cathode, the cells will not function properly. Kappes: Just a few comments on cell design. In an alcohol stripping circuit we are running in Beatty„ NV, we are using PVC pipes for all circuitry piping and a commercial polypropylene electrolytic cell. They seem to be working quite nicely. The cell itself has eight cathodes measuring 18 in2. At six gallons per minute flow into the cell, at an average gold content of about 500 ppm, we seem to get good loading on the first three to four cathodes and not much on the end cathodes. At 12 gallons a minute flow we seem to be seeing gold uniformly along all eight cathodes. We are running at quite a high amperage level, about 400 amps into that cell. Gene McClelland, US Bureau of Mines, Reno Research Center (from the floor): I was associated with a company where the packing density of their steel wool cathodes was much too high and created some short-circuiting problems in their electrowinning circuit. I would like to ask the panel if they can recommend a packing density for cathodes in pounds of steel wool per cubic foot. Hall: The weight of steel wool put on one of our cathodes is 10 lb and the dimensions of the cathode are such that density would be about 0.75 lb/ft3. Duncan: I made a rough calculation and I'm estimating about 2 lb/ft3. Potter: In checking over a number of electrowinning operations, I found apparently very satisfactory operation within the limits that have been mentioned. I have come to a figure of about 0.5-1.0 lb of medium grade steel wool per cubic foot packed as uniformly as possible, of course. One consideration in packing is the fact that there should be good contact between the steel wool and the conductor. Operators tend to compact the steel wool more than would be desirable just to try to maintain good contact.

Jan 10, 1981

By W. F. Visser

The growing availability of information and data analysis capabilities of recent years provides new opportunities for improving the performance of mining operations. By using real-time measurements and artificial intelligence, it is possible to respond faster to changing conditions, while accurate and timely information permits rapid evaluation of changes and fast business improvement decisions. This article presents a blueprint for alignment of systems, organizational design, and management practices to leverage these developments in performance-driven operations management in mining and mineral processing. The first component of the blueprint is a performance framework with a system of key performance indicators for production control that can be used across organizational levels. This system places improvement at the core of management activities, giving greater importance to improvement skills at lower organizational levels, so companies can leverage available information for improving operational control. Secondly, the blueprint defines an organizational structure that strengthens performance improvement with technological and change management capabilities. Finally, the blueprint proposes alignment of management practices, covering the optimization of short-interval controls, the application of an improvement project portfolio management system that determines the ownership of improvement projects, and the coordination of controls across the organization. This combination of systems, organizational design, and management alignment supports rapid decision-making at the right organizational level. Introduction of the presented blueprint for operations management enables mines to leverage the developments in information and analysis capabilities to improve the performance of operations.

By J. Drelich, M. Pawlik

An improved experimental procedure to measure contact angle has been consolidated with coal surface preparation involving polishing with abrasive paper, alumina powder, and a cloth, followed by ultrasonic and mechanical cleaning. Specifically, the captive-bubble measuring technique has been compared with the sessile-drop technique and the former has been recommended for the examination of the hydrophobic properties of coal surfaces. Results of the research program, which is currently under way, on the examination of the effect of the nature, amount, size, and distribution of mineral inclusions in coal, on its wettability are briefly reviewed.

Jan 1, 1999

By Helmut Hass, Michael B. Gilbert

The extension of the commuter railway system (S-Bahn) in Leipzig, Germany willrequire the construction of an underground line crossing the downtown area of thecity to tie the Bavarian Station in the South to the Main-Station in the North. The City-Tunnel-Leipzig is currently one of the largest infrastructure projects in Europe. This system extension will have a length of approximately five kilometers. 3.9 kilometers of that length are currently being constructed using either cut & cover construction or tunnelingmethods. The design and construction of this project currently is and will continue facing very significant challenging urban and demanding geotechnical conditions.

Jan 1, 2007

By A. Schaum

On average, there are approximately 10 fatal haul truck accidents per year. The most common causes for haul truck accidents include mechanical problems, inadequate training and insufficient road/berm maintenance. Due to the frequency and magnitude of haul truck accidents, new training methods are being investigated. With the widespread availability of computers and new technology becoming more reasonably priced, the ability to incorporate computer-based training for miners is becoming more possible. It has been shown that computer-based training is just as effective in knowledge acquisition as traditional lectures, and computer-based training can lead to a significant increase in the retention of material (Williams and Zahed, 1996). Studies have also shown that more engaging training methods lead to more effective knowledge acquisition (Burke et al., 2006). A supplemental system for current and new miner training to address the common causes of fatal accidents was developed. The training system is a virtual preshift inspection of a haul truck, and it can train new haul truck operators to identify parts that look defective. The training will increase an operator?s ability to recognize problematic parts and correctly identify the corrective action needed. Increasing the quality of training by providing an engaging, simulated hands-on environment will lead to safer behaviors by trainees, which will ultimately lead to fewer accidents and fatalities.

Jan 1, 2008

By K. Ward

The Environmental Protection Agency (EPA) is beginning to provide compliance assistance visits to various industries, including mining, for Emergency Planning and Community Right-to-Know Act (EPCRA) compliance. The EPA inspectors may consist of a multi-media team deployed to review systems and procedures for EPCRA Sections 302, 304, 311, and 312. The Team’s focus may include emergency response plans, training programs, qualifications of personnel, and release notification protocols. This presentation takes a look at the EPCRA compliance challenges faced by Arizona copper mining and processing facilities.

Jan 1, 2001

By P. Rosten

US mine production of iron ore in 1984 showed some improvements compared to 1983. But reduced demand from the iron and steel industry caused temporary shutdowns of many iron ore mines and pelletizing plants. US raw steel production in 1984 was slightly above 1983, but still at a depressed level. Production was 83 Mt (92 million st), compared with 77 Mt (85 million st) in 1983 and 68 Mt (75 million st) in 1982. Two major production trends continued in 1984. They were the increased production from electric furnaces and the growing use of continuous casters. Electric furnace production included 33.2% of the steel poured in 1984, compared with 31.5% in 1983. Continuous casting was used for 39% of 1984 steel production, compared with 32.1% in 1983. Statistical Process Control Statistical Process Control (SPC) has taken on new proportions in the iron ore and steelmaking industries within the last year. This mathematical technique is used to monitor, control, evaluate, and analyze a manufacturing process. The technique charts variability of important quality parameters. Training and adaptation of SPC techniaues for process control have been initiated at Inland, Steel's Minorca, Pickands-Mather's Hibtac, Cleveland-Cliff's Empire and Sherman operations, and at Reserve Mining. One of these operations has requested its bentonite supplier provide SPC charts on quality specifications. Some of the steelmaking operations (Inland Steel, Bethlehem Steel, Dofasco, LTV Steel, National Steel, Stelco, Weirton Steel, and Wheeling-Pittsburgh) have set up SPC programs within their operations. And they also have insisted that some of their suppliers use SPC. Plant Shutdowns The permanent closure of Stelco's Griffith mine at Red Lake, Ontario, has been delayed by one year. This gives employees more time to adjust. The mine is now set to close in April 1986, instead of April 1985. Sidbec (Canadian government) and its other partners (including British Steel Corp., Quebec Cartier Mining, and US Steel) closed its iron mining operations at Gagnon, Quebec. The pellet plant has been leased to Quebec Cartier. New Iron Ore Operations The massive Carajas iron ore project in Brazil is scheduled to come onstream in Jan. 1986. It is to achieve full-scale commercial shipments by July of that year. The 66% iron crude ore requires only crushing and screening before shipment. The product consists of 83% sinter feed and 17% coarse ore. Annual production capacity will be 32 Mt (35 million st) when the project is completed. Principal customer for the ore is Nippon Carajas Iron Ore Co., a consortium of Japanese steel mills. The Arab Iron & Steel Co. (AISCO) has started up a $US300 million, 3.6 Mt/a (4 million stpy) iron ore pelletizing plant built by Kobe Steel Ltd., at Al Hidd-hide in Bahrain. By 1986, this grate-kiln-cooler plant will supply high quality iron ore pellets to feed direct reduction plants in the immediate Gulf area and Far East markets. Iron ore supplied from Brazil, Peru, India, and Mauritania provides the feed to the pellet plant. Hydrated lime (2%) is used as a burden.

Jan 5, 1985

By R. L. Grayson

In 2010, MSHA began holding hearings on a new coal mine respirable dust rule, which proposes a 1.0 mg/m3 standard, a separate 0.1 mg/m3 quartz standard, and the use of single-shift samples for compliance. Small mines largely comprise the ?hot spots? where dust diseases of the lungs increased dramatically over the past decade. This paper presents findings on the feasibility of small mines? compliance with the proposed new 1.0 mg/m3 standard. It gives probabilities of noncompliance by MSHA district, seam height, and selected ?hot spot? counties. Because silicosis and respirable quartz dust appear to be the primary issues related to a recent doubling of the prevalence of dust diseases of the lungs, multiple regression models for prediction of the average total quartz content of compliance samples are given. These findings have significant implications on the need for better dust control methods.

Jan 1, 2012

Attractive geology does not guarantee mining investment if a region’s policies are bad, according to mining executives surveyed in the Fraser Institute’s seventh Annual Survey of Mining Companies. Companies responsible for a combined US$642.4 million in international exploration (during 2002) rated the policy attractiveness and mineral attractiveness of mining jurisdictions around the world. Jurisdictions like Chile, Australia, Quebec and Nevada bolster their attractive geology with mining-friendly policies, the report said. These locations do well on the overall investment attractiveness index. On the other hand, jurisdictions like British Columbia and Indonesia, each with excellent geology, are hurt by their policies, which have lowered their score.

Jan 1, 2004

By R. P. Stahura

Conveyors are the lifeline of mining and processing operations. They continuously supply materials to and carry finished products and waste away from operations. When conveyors are running at less than maximum efficiency, the operation's productivity is in trouble. Inefficient conveyors suffer carryback, leading to the buildup of materials on idlers and other expensive components. They spill and leak material at loading zones and conveyor transfer points. This causes accumulations that can damage the belt, wear moving components and increase both clean-up labor and maintenance expenses. They wander or mistrack, spilling material and endangering personnel and conveyor components. And through these inefficiencies, they multiply the operation's hidden costs. These added expenses occur in lost production, increased downtime for service and maintenance and replacement costs for prematurely worn equip¬ment. In addition, the attitude that inefficiency is "good enough" is recognized elsewhere in the organization. As a result, other departments relax or operate at less than peak performance. Quality goes down along with employee morale. Costs of inefficient conveyors A key to efficiency is handling a product as few times as is necessary. That means conveyors should be loaded, track true to the unloading point and then be unloaded, all without material escape or waste motion. An inefficient conveyor is often signaled by accumulations of DURT - material that has escaped from the system and is now at large in the plant. This DURT adds costs to an operation that are uncounted and, perhaps, uncountable.

Jan 1, 1992

By Richard Kastner, Emilie Vanoudheusden, Fabrice Emeriault, Jacques Robert

INTRODUCTION The subway line B of Toulouse (France) has been realized with three different tunnel boring machines (TBM) techniques: Contracts 2 and 5 are excavated with earth-pressure balanced TBM, Contract 4 with a slurry shield TBM, and Contract 3 with a compressed-air TBM. The first three machines are around 7.7 m in diameter, while the last one is 5.3 m. Moreover, a small part of the line (50 m) has been excavated by a conventional method. The tunnels run through the Toulouse molasses, composed of hard sandy clay with pockets and lenses of dense sand. Geotechnical investigations have shown that in these formations, K0 is greater than 1, around 1.8 at a depth of 25 m (Serratrice,2005) and that geotechnical characteristics are homogenous on the whole layout (? =22 kN/m3, Su = 300 kPa, c' = 30 kPa, F' = 32°). The water table is found between 2 and4 m below ground level. As geology, stratigraphy and tunnel cover (between 10 and 20 m) are almost identical, a comparison of movements induced by the excavation by each of the four excavation techniques is possible. This paper presents the soil mass movement measures in the case of the conventional excavation method and in the case of TBM sections. It shows how tunneling parameters may explain the different surface movements observed during excavation. For the sake of simplicity, only the results of Contract 2 (earth pressure balanced TBM)will be presented. MONITORING Monitoring for the Conventional Method Section For the conventional method section (Vanoudheusden et al. 2005) the mass soil movements are measured with two inclinometers and one multi-point extensometer borehole with automatic data acquisition (Figure 1). The monitoring devices include

Jan 1, 2007

By Jerry Pyatt

Lead has been used by mankind since before the Egyptian pyramids were built. Its durability provides for a continuum of innovation. As the largest integrated lead producer in the Western Hemisphere, The Doe Run Co. is committed to locating, mining, processing and sup-plying lead in ways that are responsible and sustainable. It takes ingenuity and resolve to successfully operate in the heavy industry field today. Doe Run is committed to applying responsibility through sustainability, lean manufacturing, safety, environmental stewardship, education and workforce development, and com-munity support.

Jan 1, 2008

By Franklin J. Stermole

L. Alan Weakly, member SME, is a senior staff engineer, Exxon Co. Weakly chaired a Mining Engineering committee formed to solicit materials for six planned "personal skills" articles, to be used in ME this year. What follows are Weakly's introductory comments to the series. Upon graduation from college several years ago, I thought that I was sufficiently prepared to embark in my chosen profession. A short time later I realized that several years of on-the-job training was going to be required before I could use my technical training effectively. It never occurred to me that, professionally, I was seriously lacking in any other skills. My spelling could use a little upgrading, but this was not a serious deficiency. I have been very fortunate to have had two employers that recognized that their engineering professionals did lack other skills and made every effort to give them training to correct these deficiencies. The skills I am referring to are those in administration and interpersonal relationships. Most mining engineers and geologists receive very little, if any, college training in these areas. In addition, many companies do not provide this training and many mining engineers and geologists are unaware of their deficiencies. It is for this reason the subject of personal skills development is being introduced in Mining Engineering. The mining engineer or geologist can pursue one of two basic career directions, managerial or technical. In today's technically sophisticated society and highly competitive business climate, both orientations require administrative and interpersonal skills. Most of us are technically qualified and we continue to upgrade our technical skills. But many studies indicate that we, as a group, are significantly weaker in administrative and interpersonal skills than other professional groups. In addition, these studies indicate that engineers, in general, take longer to reach managerial levels and fewer do so. This series in Mining Engineering, then, should help readers strengthen and broaden their professional capabilities. In all industries, including mining and petroleum, economic analysis of potential investment projects is done to select the projects that will give maximum future value from the investment of available capital. Rather than looking directly at the future values to be generated by investing capital in alternate ways for economic decisions, evaluators usually use either rate of return, present value, annual value, a profit to investment ratio, or various break even analysis results to reach economic analysis decisions in evaluating alternative investments. Alternative economic evaluation techniques are used in industry to properly analyze the economic potential of various investment projects. "Discounted Cash Flow" analysis is the phrase commonly used to describe these techniques. Whether you want to analyze projects in mineral, petroleum, real estate, refining, pipe-line transportation, or any other industry, proper application of discounted cash flow analysis techniques enables you to fairly compare the economic potential of alternative projects as well or better than you can using any other project evaluation approaches. It should be pointed out that investment analysis generally involves more than economic analysis. Financial and intangible considerations sometimes are as important or more important to investment decision-making than economic considerations. Economic analysis refers to evaluation of the profit generating potential of projects, that is selecting which alternative projects will generate maximum future value possible from available investment capital. Financial analysis, on the other hand, relates to analysis of where money is going to come from to finance various projects. Regardless of the economic potential of a project, if financial analysis indicates that we cannot finance the project, it likely will be shelved for financial reasons even though it may be economically satisfactory. Many evaluators use the terms "economic analysis" and "financial analysis" interchangeably, but this author considers that to be undesirable. Intangible analysis relates to project factors that are difficult to quantify in

Jan 2, 1984

By John C. Nigro

Bench scale and pilot plant research was conducted using dolomites (CaO,MgO) lime as the basic additive in the preparation of self-fluxed pellets from a typical magnetic taconite concentrate (5.57 S_2). The specific objective of this investigation was to ascertain the viability of the magnesia lime pellets in high temperature oxidizing and reducing atmospheres. Pellet basicity and induration temperature were major parameters affecting fired pellet quality; temperatures ranging from 1,200° to 1,250" C appeared to be the most favorable for production of self-fluxed pellets with basesities (B) above 1.0. Comparison of the mechani¬cal and metallurgical properties of regular (acid) and self-fluxed pellets (B 1.55) produced under similar conditions in a modified grate pelletizing machine showed that the self-fluxed pellets were more resistant to abrasion and to high and low temperature reduction disintegration, an important consideration in commercial application. The Plus 3 mesh Linder index increased from 68 percent (regular pellets) to over 90 percent (self-fluxed pellets). The reducibility and swelling indices of the self-fluxed pellets were found to be comparable to the regular pellets.

Jan 1, 1972

By Ray Hutton, Darrell Liebno, Taro Nonaka

Background Population growth and increasingly stringent regulatory controls on water quality across North America have resulted in municipal governments investing heavily in infrastructure to control what are known as Combined Sewer Overflows (CSOs).These are events which occur when combined sewers exceed their conveyance capacity during periods of heavy rainfall or snowmelt. The city of Atlanta, Georgia is one such municipality; with a population of over450,000 within city limits and a sewer system servicing 1.2 million including adjacent jurisdictions, the City of Atlanta has a Combined Sewer System (CSS) encompassing approximately 15% of its total 3,540 km (2,200 miles) of sewers. Atlanta’s CSO discharges to local watercourses began to draw fire from environmental groups in the1980s. As a result, in the early 1990s, the City constructed a series of CSO control facilities which provided screening and chlorination at seven CSO discharge points across the CSS watershed. Unfortunately, these facilities were not capable of handling all of the overflows generated due to heavy storm events; frequently, untreated water was bypassed around the treatment facilities. The federal Environmental Protection Agency (EPA) deemed that water quality standards were being violated by these discharges, and a suit was brought against the City to force a higher standard of compliance. As a result, the City entered into a federal Consent Decree which would bring CSOs into compliance with federal standards by 2007. A critical component of this plan was the design and construction of the West Area CSO Tunnels and Pumping Station. In February 2003 the City’s Department of Watershed Management retained the services of Jordan Jones & Goulding/Hatch Mott MacDonald/Delon Hampton Associates (JDH Joint Venture) to design and provide construction management ser-vices for the project, which was designed to capture combined sewage from three of the City’s existing CSO facilities on the northern end of the CSS watershed. The design consisted of two connected tunnels which would convey the wastewater originating from the North Avenue, Clear Creek, and Tanyard Creek CSO facilities to a submersible wet well pumping station located at the R.M. Clayton Water Reclamation Center (WRC). Since the majority of the effluent stream consisted of storm water, the City elected to design and construct a separate treatment plant. This plant was designed under a separate contract, and is currently under construction.

Jan 1, 2007

By Edward Holloway

The basis for the selection of the ultimate pit for an open-pit mining operation is generally opaque. Some form of value-based analysis will generally guide the final decision; however, the value will often gradually plateau while the ultimate pit size continues to increase. There is no established framework to guide specialists in the selection of the ultimate pit, with such decisions regularly made on a somewhat arbitrary basis. The key component that is missing from the analyses typically used to select the size of the ultimate pit is risk. Once risk is quantified within the analysis framework, the decision-mak-ing range is significantly reduced and the process for select-ing the ultimate pit becomes more consistent, replicable and defensible. The technique outlined in this paper provides an approach to including risk in the process used to select the ultimate pit.

Jun 1, 2024