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By J. G. Groppo

Laboratory settling and filtration testing was conducted on wet processed fly ash in order to determine the applicability of conventional dewatering techniques to reduce the moisture content prior to drying. Settling tests showed that acceptable clarity (<1.5 g/l suspended solids) could be achieved after as little as 6 minutes of settling. After settling to a consistency of 40 weight % solids, continuous laboratory vacuum filtration testing produced a cake containing below 20% moisture with throughput exceeding 150 lb/ft2/hr.

Jan 1, 1997

By AIME AIME

The following abstract of the minutes of the final Adjourned Annual Business Meeting, held Nov. 12, 1912, in the office of the Institute, 29 West 39th Street, New York City, is here presented for the information of the membership at large. On the announcement by the Secretary that there was a quorum present, President James F. Kemp called the meeting to order. The minutes of the Adjourned Annual Business Meeting of Oct. 7, 1912, were read and approved. (Sec p. xi,Bulletin No. 71, November). Prof. Jos. W. Richards, in behalf of the Special Committee of the Board of Directors and the Council (Messrs. Richards, Kirchhoff, and Rand), withdrew the two proposed amendments to the Constitution offered by the said Committee at the Adjourned Annual Business Meeting of Oct. 7, 1912. (See Bulletin. No. 70, October, 1912, p. vi., and Circular Announcement No. 8, Oct. 15, 1912, p. 15.) Professor Richards presented a syllabus of the proposed amendments to the Constitution and By-Laws prepared by the Special Committee. Several members present discussed various sections of the proposed Constitution, and the Committee advised that the suggestions would he duly considered before submitting the final document, which would be duly presented and sent to the membership at large at least 30 days before the next Annual Business Meeting, Feb. 18, 1913. Professor Richards presented a resolution, seconded by Mr. Kirchhoff, making a change in the present Certificate of Incorporation, so that it would conform to the proposed changes in the Constitution and By-Laws; said resolution was unanimously adopted. Professor Richards presented another amendment to the Constitution, which had been purposely omitted from the printed list, but had been requested by many members, namely, the creation of a " Class of Fellows." This question was freely discussed at the Cleveland meeting (see Bulletin No. 71, November, 1912, p. 1348), and in view of the diversity of opinion it was-decided to present it in separate form for separate action of the membership at large at the Annual Business Meeting, Feb. 18, 1913. In answer to question, the President announced that the proposed amendments to the Constitution and By-Laws presented by Messrs. Corning and Stone at the Adjourned Annual Business Meeting, Oct. 7, 1912, and published in Circular Announcement No. 8, Oct. 15, 1912, were still on record. Professor Richards presented a syllabus of the proposed amendments to the By-Laws, and several sections were discused by members present, but no action of record was taken. Mr. Charles F. Rand read a letter from Mr. L. K. Armstrong, Sec-retary of the Spokane Local Section of the Institute, referring to the proposed amendments to the Constitution, and he announced that many of Mr. Armstrong&apos;s suggestions were, in one form or another, already incorporated in the proposed amendments submitted by the Special Committee. A special vote of thanks was passed to Dr. Albert R. Ledoux for the valuable assistance rendered by him to the Special Committee in the preparation of the proposed amendments to the Constitution and By-Laws.

Dec 1, 1912

By Patricia Pride, Mike Robison, Jon Bergenthal, Wojciech Klecan

"The Lower and Middle River Des Peres (LMRDP) CSO Storage Tunnel is the largest single component of Metropolitan St. Louis Sewer District’s (MSD) CSO control system improvements planned to meet consent decree requirements for MSD’s Lemay Service Area. The 13.7-km (8.5-mile) long, deep, hard rock tunnel will have a finished diameter of 9.1 m (30 ft). Beginning at the Lemay Wastewater Treatment Plant (WWTP), the alignment follows the channelized River Des Peres to the outfall of the existing Forest Park tubes, as indicated in Fig. 1.The project includes three construction shafts, 34 intakes and a deep, cavern-style pump station located adjacent to the WWTP. The tunnel will be driven from the Defense Mapping shaft to the Macklind shaft. Another shaft is located near the midpoint at the tunnel in River Des Peres Park.The Forest Park intake, located at the upstream end of the tunnel just beyond the Macklind shaft, is a large, tangential vortex intake structure. With a peak flow rate of 170 m3/s (6,000 cfs), it will have a 6.1-m (20-ft) diameter dropshaft to transfer flow into the tunnel.The project includes another three large tangential vortex-flow intake structures with peak flow rates ranging from 28 to 44.5 m3/s (990 to 1,570 cfs). These large intakes are located at points where three large sewers (formerly creeks) enter the River Des Peres. Dropshaft diameters for these intakes range from 3 to 3.7 m (10 to 12 ft) in diameter. The 30 remaining intakes are smaller tangential vortex-style, with dropshafts in the range of 0.8 to 1.7 m (30 to 66 in.) in diameter.Each intake structure drops flow into a deaeration chamber constructed adjacent to the tunnel at tunnel depth. Intake tunnels transfer flow from the deaeration chambers to the main tunnel. Most of the intake tunnels are short. However, two are long. The Glaise Creek tunnel will extend 762 m (2,500 ft) from the main tunnel to the Alaska Park intake, while the Rock Creek tunnel will extend 823 m (2,700 ft) from the main tunnel to the Rock Creek intake. The dewatering pump station, located at the downstream end of the tunnel, will be built inside a large, horseshoe-shaped cavern with two access shafts. Excavation of the cavern and its access shafts will be performed by the tunnel contractor. Build-out of the dewatering pump station will be performed under separate contract."

Jun 1, 2019

By Stephen Liu

Tunnel excavation while mining is not often performed in North America primarily due to access constraints in both operations. Referencing European approaches for long distance tunneling, the Devil?s Slide Tunnel project has applied innovation and technology to provide the ability to overcome this unique challenge. The Devil?s Slide Tunnel requires the construction of twin bore tunnels excavated based on sequential excavation method (SEM) construction methods using New Austrian Tunneling Methods (NATM) principles. The twin tunnels are approximately 9 m (30 ft) in diameter and 1,250 m (4,100 linear ft) in length. The purpose of this project is to reroute Route 1 from around the Devil?s Slide through the San Pedro Mountains crossing from Montara, CA along the south and into Pacifica, CA in the north. The Caltrans project was awarded in December 2006 for a total of $272,366,000. The job is an A+B job, thus the estimate scheme of final lining while tunnel excavation is important to save time. A+B is a method of rewarding a contractor for completing a project as quickly as possible. By providing a cost each working day, the contract combines the cost to perform the work (A) with the cost of impact to the public (B) to provide the lowest cost to the public. Concurrent mining while lining is achieved through a series of gantries and a set of tunnel forms allowing the pass-through of the excavation equipment. The tunnel lining operation passes through several phases of work that are dependent upon the progress of the tunnel excavation process. This involves unique milestones, such as the evolution of the ventilation system, development of an enlarged cross passage to allow equipment to access each tunnel from within the tunnel and, finally, the installation of an invert prior to arch lining that limits the continuity of the final lining operation.

Jan 1, 2011

By K McSweeney, A Marton

This paper discusses the development of a strategy for ensuring long-term geotechnical stability of final pit walls at AngloGold AustraliaÆs Sunrise Dam Gold Mine. The strategy makes use of improved blasting techniques, changes to the mining sequence and other geotechnical techniques. Only the blasting techniques will be discussed in this paper. These were developed from numerous trials over a period of several months from May 2003 through to November 2003. The focus was to reduce crest loss damage and thereby improve final wall integrity, maintain designed safe berm widths, and ensure long-term stability. Crest loss mechanisms are now understood and are explained in this paper. The preferred solution is outlined; which is a combination of improved blasting and changes in the mining sequence to cater for pre-existing ground conditions. These ground conditions include dynamic hyper saline water with sometimes intersecting steeply dipping discrete structures. Project requirements were defined as mitigating or eliminating crest loss using 127 mm diameter pre-splitting and targeting minimal production blasting vibration levels against the walls. Blast results were measured by post blast visual inspections and video. Blast design input utilised the predictive algorithms built into simulation software when attempting to minimise vibration levels against the walls. Protection of the already fired pre-split line is now achieved using small charges against the wall and timing sequences which form a mask for the later firing main charges. The pre-split spacing is now modified to suit the geology. There eight blast domains identified around the perimeter of the pit, each having varying joint orientation. In addition, blasting the bench adjacent to the berm crest has particular considerations not required by the middle and lower benches. The preferred solution was to purposefully translate this damaged top section of the pre-split bench into a planned subsequent dig zone. The design of this top æweightÆ is a direct response to the nature of the crest loss mechanism.

Jan 1, 2004

By S. McGinn

The Brunswick Mine Diesel Particulate Filter Study was one of several research projects initiated by the Diesel Emissions Evaluation Program (DEEP). The study was carried out at Noranda?s Brunswick Mine in Bathurst, New Brunswick by Noranda Technology Centre and Brunswick Mine personnel with the collaboration of Natural Resources Canada - Canada Centre for Minerals and Energy Technology (CANMET), National Institute of Occupational Safety and Health (NIOSH), Andreas Mayer of VERT, and diesel particulate filter (DPF) system suppliers. The study began in early 2000. Field evaluations continued for 20 months. The final report?authored by Sean McGinn?was submitted to DEEP in the Autumn of 2003.

Jan 1, 2004

By Mary Ellen Bruce Large

"In partnership with California Department of Transportation (Caltrans), Federal Highway Administration (FHWA), and with support from International Association of Foundation Drilling (ADSC), Deep Foundations Institute (DFI) organized a workshop on quality assurance (QA) practices for acceptance of post-grouted drilled shafts in conjunction with DFI’s 40th Annual Conference on Deep Foundations. The 1½-day workshop was held on October 15-16, 2015 at the Oakland Marriott City Center in Oakland, CA.Post-grouting, in the context of this workshop and report, refers to the alternative design and construction of base-grouted drilled shafts wherein a grout distribution system is installed during construction and used to grout the base under pressure after the drilled shaft concrete has gained adequate strength, resulting in a stiffer axial-compression load-displacement relationship and additional possible ground improvement effects.The primary goals of the workshop were to•?Identify and summarize the state of the practice for design, construction, inspection, verification, acceptance criteria, reliability and performance of post-grouting.•?Identify gaps and needs in quality assurance that should be addressed for successful use of post-grouting.This report is structured to follow the workshop program: workshop presentations outlined the state of practice and views from owners, engineers and contractors on acceptance of post grouting methods for drilled shafts; and subsequent workshop discussions attended by a small invited group of participants focused on identifying areas of agreement and disagreement on post-grouting best practices, acceptance criteria, design and verification procedures, and inspection requirements. A partial list of attendees of the open and closed sessions is provided as Appendix A, and copies of presentations are included as Appendix B.FHWA and Caltrans are the primary audiences for this report, and its content will be used to develop a roadmap for deploying the findings into policy and practice. The secondary audience is the broader industry group, and the report content will be disseminated in a variety of formats."

Jan 1, 2016

By Michael F. Barber

"Highway slopes are intended to remain stable over a long period of time. Unexpected slope failures can be costly in terms of human life and property damage or loss. Cleanup of failures can prove to beextremely expensive."

Jan 1, 1999

By M. Schafer

The 20 foot diameter cast-in-place tunnel lining for Phase 3 of the Mill Creek Tunnel (MCT-3) has been completed. This paper will summarize aspects of liner design and address the construction approach in placing the liner in areas of tunnel that experienced crown overbreak. Tunnel lining production rates, installation procedures and form buoyancies experienced during concrete placement will also be presented.

Jan 1, 2008

By M. Schafer

The 6-m- (20-ft-) diameter cast-in-place tunnel lining for Phase 3 of the Mill Creek Tunnel (MCT3) has been completed. This article summarizes aspects of liner design and ad-dresses the construction approach in placing the liner in areas of tunnel that experienced crown overbreak. Tunnel lining production rates, installation procedures and form buoyancies experienced during concrete placement will also be presented. The Mill Creek Phase 3 tunnel (MCT-3) is expected to be completed this year. It is one of the largest tunneling projects undertaken by the Northeast Ohio Regional Sewer District (NEORSD) to date. The tunnel horizon is situated within the Devonian Chagrin Shale rock formation at an average depth of 85 m (280 ft). The tunnel was excavated using a two-pass method. A full face, fully shielded, Robbins 7.2-m- (23.8-ft-) diameter tunnel boring machine (TBM) was used to excavate approximately 4,500 m (15,000 ft) of tunnel and facilitate installation of initial supports (first pass). The final lining (second pass) consists of 305-mm- (12-in.-) thick cast-in-place reinforced concrete and integral low flow channel. Seven shafts were constructed on the project. The excavation of the tunnel commenced at Shaft 14 and proceeded down grade to Shaft 9, the terminus shaft. Because of the presence of overbreak in the tunnel crown, measures were required to support the form and counteract the effects of buoyancy during concrete placement.

Jan 1, 2008

"In the first half of 1990, Cambior earned $1104 million, or $0.37 per share, on revenues of$66.4 million. The company&apos;s strong cash position, attained late in 1989 and in the beginning of1990 through the exercise of warrants, put working capital at $83.8 million as of June 30, 1990. Long-term debt was reduced by over $10 million during the weak gold market, leaving the company with a debt to equity ratio of only 0.03. Production for the six first months of 1990 was 107 720 oz. Au, an increaseof24% over the corresponding period in 1989.Financial Profile/Results and Corporate Financial StrategiesTotal revenue for the 1989 fiscal year was $116,883,000 compared to $109,848,000 for 1988. The 1989 results achieved despite a lower average gold price, resulted from a higher level of commercial gold production and a 115% increase in investment income over 1988. Investment income rose to $3,568,000 in 1989 due to higher levels of cash assets.Cambior&apos;s mine operating costs increased 19% to $68,561,000 in 1989 from $57,472,000 in 1988. This increase resulted from rising operating costs at the Doyon Mine ($250/oz to $274/oz) due to the shift from open pit to underground operations, as well as from the start -up of three new mines with relatively higher costs. These costs have reached a stable level that should be maintained for the next few years.In 1989, net exploration expenses were $6,838,000, down 31070 from 1988, partially due to the Canadian tax reforms introduced since 1987. Depreciation and depletion grew by $1,432,000 in 1989, reflecting a higher volume of commercial production from the Pierre Beauchemin, Lucien C. Beliveau and Chimo mines.Net earnings for 1989 amounted to $17,661,000 or $0.73 per share compared to $17,438,000 or $0.74 per share in 1988.Cambior has an exceptionally liquid and strong balance sheet. As at December 31, 1989, net working capital stood at $85.6 million, with a total assets base of $338.6 million. With a long-term debt (including gold loans) of $21.5 million and shareholders&apos; equity of $277.2 million, Cambior has a debt to equity ratio of 8%. All but about $100,000 of long-term debt is in the form of gold loans.The total market value for Cambior&apos;s stock as at September 10, 1990, stands at $420million, based on recent stock market prices. Cambior&apos;s stock and warrants are traded on the Montreal and Toronto Stock Exchange."

Jan 1, 1990

"This paper challenges the traditional notion that mine planners need to plan production so as to incur the lowest mining cost. For a given mine configuration, a mine that increases its mining rate will incur increased mining costs. In an environment in which operations are fixated on cost reduction, a proposal that increases costs will not be readily accepted. Such a proposal requires financial justification—the increase in costs might be recuperated by the additional production. This paper evaluates the net present value (NPV) across a range of copper prices for two underground orebodies located at different depths, using a production rate of 300 kt per quarter and a scenario that introduces additional equipment and costs for 450 kt per quarter. The evaluation was based on the changes of NPV for the orebody located at a shallow depth compared with the orebody at a greater depth. Discrete event simulation combined with mixed integer programming was used for analysis. Unlike traditional sensitivity analysis, this study re-optimizes the mine plan for each commodity price at each production rate. The results show that, for the low mining rate at the final copper price, an NPV of A$1530.64 million is achieved, whereas an NPV of A$1537.59 million is achieved at a higher mining rate. Even though pushing mining rates beyond traditional limits may increase mining costs, this option may be beneficial at certain commodity prices, particularly when prices are elevated. IntroductionA traditional notion among mine planners is that mining rates should be planned in such a way as to reduce production costs. This concept generally relates to the mining rate that results in the highest machine utilization for the selected equipment. Although an existing mine may consider increasing its mining rate by adding equipment to a given mine configuration, this typically increases mining costs. In an environment in which operations are fixated on cost reduction, a proposal to increase costs may be very difficult to argue for. The value of the mine plan is well recognized as varying with the mining rate for a given orebody (Smith, 1997)"

Jan 1, 2017

By C. A. Roberts

What are the benefits and limitations of financial analysis software as a decision making tool in the mining industry? Traditionally, the assumptions and simplifications imposed by complex and uncertain information have been viewed as the main obstacle to reaching an optimum decision. Recently, however, phenomena such as corporate culture and power structure have received increasing attention as significant influences on organizational decision making processes. Studies of these phenomena have suggested an alternative way of understanding decision making processes and an alternative view of the role played by computer analysis in such processes. This paper presents these two views of decision making, and examines what each implies about the role of financial analysis software as a decision making tool in the mining industry.

Jan 1, 1992

By A. H. C. A. Zimmerman

WE have just heard what must be regarded as a thoughtful, constructive and somewhat painful analysis of the financial function of our industry. While thinking about this, it is interesting to reflect on the conditions which have stunted the growth of the financial side of our affairs. Mining must be regarded as a wealthy business. •while immeasurable grub takes and development budgets have been lost, there can be little argument that a productive ore-body nearly always produces the type of wealth that breeds some extravagance. I recognize that this statement can be attacked from many sides, but an historical comparison with a commercial enterprise involving similar investment will demonstrate what I mean. However, these old times are be-ginning to disappear for a variety of reasons. High amongst these are: ( l) Increased costs of exploration. (2) Remoteness of many new finds. (3) Fixed or declining metal prices (particularly when expressed in constant dollars). ( 4) Constant demands for higher wages.

Jan 1, 1962

A variety of environmental financial assurance instruments are in use across the globe. This paper reviews some of the more common forms currently used in New Zealand, Canada, USA and Australia. In order to be effective, the form of assurance instrument selected needs to be aligned with a countryÆs specific environmental objectives, geography and political climates and also allow for a healthy investment climate. Industry and Government both have a strong interest in ensuring financial assurance criteria meet these objectives. &nbsp; Recently Golder Associates have been involved in financial assurance assessments for various mining and quarrying companies across the South Island. Multiple stakeholders and regulatory agencies can make the setting of effective and fair financial assurance criteria a complex exercise for both regulatory agencies and industry. &nbsp;The author relates experience gained in assessing financial assurance under current New Zealand legislation (RMA, 1991), effectively dealing with issues such as ôdouble bondingö and overviews potential approaches to dealing with transitional issues for historic and existing operating mine sites.

Jan 1, 2006

By D. Drymonitis, G. Gialoglou

"Placer gold mineralizations have been observed in the north-eastern parts of Greece. Some of them have been at first evaluated to be of special interest so, exploration campaigns have been designed and carried out. Among the other exploration techniques applied on the sites of interest, drilling was the one to give the detailed information and data for the evaluation of the deposits. Having collected the data from trenching and two consecutive drilling campaigns, they were processed geostatistically to estimate the ore reserves and therefore the economic interest of the deposits. The latter was done by using exploitability indices, which would give a rough idea whether the deposits were economically feasible. A small number of such deposits have been spotted in the area and have been explored and evaluated as above. The present paper deals with the most important of them, giving all the process followed and the results derived from the exploration carried out."

Jan 1, 2005

By Xu C

This paper describes the structure and operation of an interacth.. computer program for mineral industry financial analysis and production planning. It includes comprehensive risk analysis with correlated variables and optimal production scheduling using Lane&apos;s balancing cut-off grades and the general dynamic programming approach.

Jan 1, 1995

By Sarah R. Hindle

Carbon capture and storage has jumped to the forefront of climate change mitigation efforts for its capacity to sequester large amounts of carbon. Mineral carbonation is one prominent option, mimicking and accelerating the natural weathering process of certain silicate minerals. This has the ability to produce stable carbonate minerals that can store carbon on geologic time scales with little to no risk of leakage. Commercialization of this process is ideally suited for integration into the proposed mining operations at the Turnagain Nickel site in Northern BC. This is due to the abundant supply of suitable ultramafic feedstock material, as well as the economic benefit of sharing costs while reducing net emissions and bringing value to otherwise valueless and costly waste rock. While studies have shown this process to be technologically viable on a laboratory scale, assessing the economic and financial viability of such a process on an industrial scale is necessary. An evaluation of the financial feasibility of integrating mineral carbonation into the mining cycle at Turnagain under a proposed cap-and-trade system is presented.

May 1, 2010

In constructing a financial model of a project significant effort is expended on capital and operating cost estimation, commodity price forecasts, and choice of discount rates while uncertainty in the primary input, the reserve, is often completely overlooked. The aim of this paper is to highlight the impact of uncertainty in the resource/reserve estimation process on the assessment of the financial performance of a project. Four qualitative processes have an impact on resource/reserve uncertainty. These stages are: 1.Ore definition 2.Geological interpretation 3.Resource estimation 4.Ore reserve estimation and mine planning. Each stage contains a number of tasks that may be considered as key performance activities (KPAs). Optimizing the manner in which these KPAs are completed can remove a great deal of uncertainty and error from the resource/reserve process. Examination of these KPAs within a company can also provide an insight to the quality of the information underlying the project. This will allow the company to identify any shortcomings in the data and to assess the resulting risks (Gilfillan, 1998). A hypothetical financial model based on a gold operation has been used to estimate the potential effect of resource/reserve uncertainty on revenue. Monte Carlo simulation has been employed to simulate a number of hypothetical scenarios: 1.a base case scenario which assumes no major errors or biases, but contains realistic margins for uncertainty that would exist in any project where work is being completed to the limit of best endeavours 2.a poor sampling scenario which assumes poor sampling practice and lack of understanding of sample preparation 3.a poor resource estimation scenario which assumes poor modelling and inappropriate choice of interpolation technique, and 4. a ?typical? scenario which represents a project where the majority of KPAs are not performed as best as they could be. The results show that realistic uncertainty ranges can generate changes in the estimate of potential revenue of plus or minus 30%.Therefore, it is important to allow for errors in these processes in any financial analysis or feasibility study. It is recommended that, when building a financial model, are view of relevant resource/reserve KPAs be carried out and appropriate ranges for uncertainty be applied to provide a range of potential outcomes. These outcomes can then be factored into the detailed cash flow analysis in order to ensure that technical uncertainty is built into financial decisions.

Jan 1, 1999

By S G. Gemell

"The financial model is an integral component of any project evaluation based on mineral resources, ore reserves and (at least internally) exploration targets. Given the unity of purpose for preparing financial models for project evaluation purposes, the diversity of both format and content of the finalised models is surprising. Many models are prepared by staff or consultants who are comfortable with a particular format that may be used for other purposes, such as budget preparation or financial reporting. It is natural in these situations that the practitioner will take these models and adapt them to the purpose. The end result may or may not succeed in providing a clear, accurate and sufficiently detailed view of the project’s economic viability.When preparing a model, the practitioner should be cognisant of the interpretation and review, or audit, process. The auditor may be a consultant or employee of a bank, potential equity provider or of the project sponsor itself. Depending upon the scale of the project and the level of participation of the entity that the auditor represents, the financial model will be interrogated more or less rigorously. In any event, the end user will require the model to permit easy change of inputs and will wish to confirm that such change is appropriately and thoroughly transmitted throughout.Accordingly, there are some ‘dos and don’ts’ that can be readily applied in the creation of the financial model that will greatly assist the end user, not just in the change of inputs, but also in reviewing the model’s integrity. The less time and effort required by an auditor in this regard is reflected directly in the cost of the review process.CITATION:Gemell, S G, 2016. Financial modelling with the auditor in mind, in Proceedings Project Evaluation 2016, pp 172–180 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 8, 2016