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By Kevin Fitzpatrick, Carmen Scalise, Patrick Jensen

"The Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) owns and operates the Tunnel and Reservoir Plan (TARP) system which was adopted in 1972. TARP is a network of 110 miles of deep tunnels and ultimately 3 large reservoirs to combat waterway pollution and flooding within a 350 square mile area served by combined sewers. The original TARP concept included additional tunnels to convey CSOs from the largest storms to the reservoirs. With the initial TARP tunnels complete and the reservoirs nearing completion, MWRDGC commissioned hydraulic and hydrologic modeling studies to analyze the benefits of additional conveyance tunnels. These updated studies optimized the configuration of additional tunnels considering integration with potential future local sewer system upgrades. The alternatives considered several routes of 25, 30, and 35 foot diameter tunnels, ranging from 10 to 18 miles. Alternatives were analyzed based on projected reductions to basement flooding compared to the relative costs. TUNNEL AND RESERVOIR PLAN After World War II the Chicagoland area underwent rapid growth and development. With the Metropolitan Water Reclamation District of Greater Chicago's (MWRDGC) service area becoming increasingly impervious, the flat Chicago landscape was increasingly at risk of significant flooding. In the mid and late 1950's, Chicago experienced multiple extreme storm events that had significant impacts on the city and generated the momentum necessary to initiate what would ultimately become one of the world's largest civil works undertakings. In 1957 a Flood Control Coordinating Committee was formed, consisting of representatives of the MWRDGC, Illinois Department of Public Works, Cook County, and the city of Chicago, to review various plans and develop recommendations for a course of action. With more than 50 alternative concepts being identified, the Tunnel and Reservoir Plan (TARP), which itself is a composite of various alternatives, was adopted the by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) in 1972. The need to adopt a long term plan was further influenced by the Clean Water Act, which was enacted only 8 days prior."

Jan 1, 2016

By Jacob Bouke, Jason Janisch, Erik Vlot

The use of conventional tailings deposition methods has been the standard for decades. With the need to reduce the impact of mining, alternative methods are considered when expanding or upgrading tailings handling systems. Converting an existing tailings management system to a more sustainable deposition method during the operation of a mine may incur considerable operational and financial risk, and when assessed more traditionally, does not provide significant advantages. As a result, most mines choose to continue their current technology and add an additional pumping stage or pumpstation to their tailings line in case of a pipeline extension or Tailings Storage Facility (TSF) expansion. This also often involves raising embankments. Changing pumping technology is traditionally assessed by comparing the energy efficiency of current and prospective pumping technology. Despite a reduction in absorbed power, this traditional assessment does not include possible savings in water and the carbon footprint. With the consideration of all these three aspects, alternative pump technologies, such as Positive Displacement (PD) technology, become more economically feasible, providing increased sustainability and enable a site to future-proof their operations. Project feasibility may be affected by the high capital investment required for PD pumps. The benefit of applying PD pumping technology could be enhanced by reducing the volumetric throughput of the pipeline by dewatering the tailings to 65% solids concentration by weight. It was found that despite increasing capital expenditure, the improved reclamation of water will have a positive effect on the direct and indirect cost of fresh water intake to mine operations. This paper seeks to illustrate that in many applications the long-term benefits of investing in sustainable tailings management are optimized when more efficient PD pumping technology is combined with tailings dewatering when upgrading or expanding the tailings handling system.

Feb 1, 2024

By C. Stacy

The mining industry is changing rapidly. Competition among OEM and aftermarket vendors increases dramatically each year as a result of mergers and acquisitions, and especially technology advancements in the mining industry. Adding value to mine operations by delivering technical value and differentiation is becoming more subtle and more difficult to accomplish. Because of this, identifying and protecting intellectual property has become more important to the product development, engineering and marketing/sales continuum than it had been in the past. How companies protect intellectual property and determine the value of those assets is critical to the sustainability and differentiation of technology providers in the mining industry.

Jan 1, 2012

By P. Lopez, E. Wellman, N. Risso, A. Anani

Current machine learning models used for roof fall hazard prediction are mounted on expensive sensors, computationally expensive, or lack the robustness for accurate prediction in the underground mining environment. This research aims to provide a design methodology for a robust, low-cost, deep learning-based algorithm for underground mine roof fall hazard prediction. A data sampling plan is developed to ensure the replicability and robustness of the developed model. In addition, feature engineering and transformation methods are described to identify relevant features for hazard identification. The methodology described here will be used in model development, tested, and implemented as a real-time mobile device application. The new tool will be expected to detect roof fall hazards in real-time and contribute to a crowdsourcing approach for underground hazard detection.

Feb 1, 2023

By James A. Finch

The Gaudin lecture is devoted to fundamentals. Given my involvement with column flotation over the last 20 years, this is my topic. I have tried to identify spinoff basic research and provide a personal list of favorites. Two are selected for discussion here. They are single bubble rise and bubble surface area flux. The rationale for such work, as well as some of the findings, are reviewed. Support for fundamental work seems as volatile as the economy (and the link is probably not coincidental). I hope some utility to the minerals industry is evident in the text. Column flotation in its current form originated in the early 1960s. The method was invented by Boutin, patented by Boutin and Tremblay and pursued doggedly by Wheeler. Their aim was to overcome the problem of mechanical entrainment of fine particles in the water carried by the bubbles, which they were convinced contributed to lowering flotation concentrate grades (Wheeler, 1988; Finch and Dobby, 1990). The solution was a combination of columnar geometry, the addition of wash water into a deep froth and the maintenance of an excess of water to the tailings, as compared to the feed (a so-called positive bias). Success at Les Mines Gaspe, Quebec, on cleaning Mo in the early 1980s signaled the start of industrial acceptance, making the column one of the flotation machines of choice today. Over the next 20 years, column applications mushroomed to cover virtually all mineral commodities, as well as nonmineral applications such as soil decontamination, deoiling of water and deinking of recycled paper. In the wake, research groups are continuing to probe the fundamentals, conferences and workshops have been transferring the technology and specialist companies have emerged to service the demand. Innovations were triggered as problems arose (for instance, in gas injection systems) and novel flotation cells, much in vogue in the 1990s, had the door opened. Mechanical cell manufacturers have not been idle - there is nothing like competition to provoke a fresh look at an established business. Flotation-cell technology has probably not seen so much activity since the patent rush in the early days of flotation, which occurred around the turn of the century. For an industry often considered reluctant to risk innovation, this is not a bad record. A good idea will find a place, but patience (not always an innovators strong suit) and careful preparation are required. Two books (Finch and Dobby, 1990; Rubenstein, 1996), three symposia (Sastry, 1988; Agar and Huls, 1991; Gomez and Finch, 1996), and a series of reviews (Dobby and Finch, 1991; Finch and Dobby, 1991; Finch, 1995; Finch et al., 1995) document the period. Like many good ideas, column flotation has been overexposed, and there have been disappointments. In a recent example, columns performing scavenging duty were replaced by mechanical cells (Chong et al., 1998). The further applications stray from the original - to

Jan 1, 1999

By W. J. Roberds

A formal and explicit yet cost-effective approach is proposed to ensure that decisions made during mine development are optimum (with respect to their ultimate consequences) as well as defensible. This risk management approach is based on probabilistic risk assessment and established decision analysis techniques, and appropriately considers the relationships among various mine development decisions, tradeoffs among consequences, the uncertainty in predicting consequences, and the benefits of flexibility to respond to changed conditions.

Jan 1, 1992

By A. A. Schweizer

This paper documents the growth and projects the future of Green Diamond Sand Products. Since1954, Green Diamond, located in Riddle, Oregon, has been producing sand from granulated nickel slag for use in various markets. Through the years, the company has seen several changes from its ownership to its product lines. In 1991, Green Diamond was producing abrasive sand at a rate of about 30,000 tons per year. It was at this time that Green Diamond became part of Glenbrook Nickel Company. Over the next eight years, Green Diamond would quadruple its production to over 140,000 tons while moving into three new markets, as well. Green Diamond is now producing sand for use in the abrasive, foundry, construction, and roofing industries. In 1998, Green Diamond again found itself under new, private ownership. With plans on developing agricultural sand and spent abrasives recycling, the future of Green Diamond appears to be one of further expansion coupled with diversification of its product lines.

Jan 1, 2000

By T. Lamond, J. O. Costello

Marble is a preferred surfacing material in up-scale buildings. Its use increased in the 1870's with rising national wealth and declined in the 1950's when synthetic materials for these applications were developed. Natural marble is now limited to high-end domestic and commercial structures. Cultured marble is a paste of white marble dust and polyester resin cured in molds yielding fixtures of specific finished dimensions. Dyes incorporated at different stages in the mixing cycle mimic shades and veining of natural marble. This paper discusses the filler requirements for cultured marble production and reviews new techniques to cut and finish natural marble.

Jan 1, 1999

By G. A. Johnson

Basic management principles will be discussed (as they apply to minerals education efforts), especially in light of the changing nature of volunteerism in today’s society. Also, the “minerals education tree” will be presented, along with public opinion / public policy realities.

Jan 1, 2001

By David Oliveira

"INTRODUCTIONOne of the key drivers for the selection of a mechanized tunneling method in good quality rock masses is a good excavation advance rate. In order to achieve satisfactory advance rates, a good geotechnical performance of the rock grippers in main beam open tunnel boring machines (TBM) is required, besides other factors related to ground support and the performance of the cutter head.One well known potential issue of main beam gripper TBM is associated with the bearing capacity of the tunnel side walls while crossing fault zones or poor rock masses in general. Such a mechanism is similar to that of footings on rock and perhaps the most common problem associated with gripper performance. Depending on the quality of the rock, the rock under the gripper contact may experience significant damage and crushing (Figure 1), eventually affecting the TBM advance rate due to a lack of tunnel wall reaction/support. Such a mechanism is primarily dependent on rock quality, applied loads and gripper size.In the case of large diameter TBMs (e.g., D > 12 m), a second potential failure mechanism may arise associated with the loss of confinement within a rock pillar between twin tunnels, even in good quality rock but particularly in bedded sedimentary strata. Punching of the rock pillar may develop due to excessive shear along bedding partings and sub-vertical joints (Figure 2), particularly under a low stress environment. As a result, this mechanism is dependent on both the rock pillar width between twin tunnels and stress conditions around the tunnels, in addition to the previous factors described for the first failure mechanism."

Jan 1, 2016

By A. Dell’Era, E. Ciro, C. Lupi

The indium recovery via electrowinning from sulfate baths has recently gained significant attention as it does not present toxic emissions, hermetically sealed system requirements, human health, and environmental hazards. Following previous works related to the optimization process for AISI 316L and Ni cathode, it was observed significant importance of the metal supports on the input and output parameters of the indium electrowinning process from sulfate solutions. Thus, comparing input and output parameters in both cases seems very interesting. Particularly, regarding the input parameters, the attention has been focused on the electrolyte composition, current density, and temperature, while productivity, morphology, and structure have been considered regarding the output parameters. Considering the productivity as the optimal output, the findings for Ni cathode were better than that for AISI 316L in most of the selected conditions studied. In the case of morphology, indium grains appear rounded and dendritic on the AISI 316L, while those on the Ni cathode show stratified lamellar grains. Anyway, the indium deposit obtained on Ni cathode shows bigger grains independently from the used operative conditions with respect to that on AISI 316L. Regarding the structure, it is clearly tetragonal, but preferential orientation, crystallinity, and deformation of the structure strongly depend on the metal support.

Jun 14, 2023

By M. Visnjic

Open Pit Mine Production scheduling under commodity price uncertainty suffers from an exponentially increasing problem size as simulations and real options flexibility are used to generate and evaluate multiple production schedules. Robustness evaluation techniques attempt to evaluate a production schedule that is generated on a single set of economic parameters against several varying prices and sources of uncertainty. This approach is invalid as the corresponding optimal LOM mine plan will change for each set of evaluation parameters. Using commodity market futures and treasury bonds as production schedule economic input parameters provides fully price and time-value-of-money risked scheduling parameters that maintain a deterministic problem size. This paper will provide comparative analysis of project NPV’s coming from traditional price uncertainty evaluation based on a single fixed LOM mine plan using varying prices versus evaluation based on varying LOM plans that are both generated and evaluated using varying prices. When cross evaluating constant price mine plans against simulations, the upside potential and downside risk of a project are significantly misrepresented. INTRODUCTION The life of mine (LOM) production scheduling problem seeks to answer the question of from where and when to extract a given block within the ultimate pit limit as well as where and when to process it. Solving this problem takes into account the constraints of extracting any particular block while seeking to maximize the net present value (NPV) of the mineral asset as a whole. A direct driver of the value of a block, and there for the entire asset, is the market price of the commodity in question. Complications arise when an optimal production schedule is attempted to be solved under price uncertainty. Many solution methodologies have been proposed in an attempt to optimize under this criterion, yet there are three salient aspects that are overlooked during this process. They are: • Generating a single production schedule and evaluating it against many simulated price paths. • Failing to understand the mechanism describing particular commodity price behavior • Inappropriate risk adjustment In an effort to address these aspects of production scheduling under commodity price uncertainty, we propose a methodology to define the economic parameters as input that is applicable to most if not all production scheduling approaches. This methodology will not only simplify the production scheduling process in terms of establishing block value but utilizes the risk adjustment of real options valuation to avoid the arbitrary blanket risk adjustment of traditional discounted cash flow valuation. Our findings conclude that attempting to optimize around individual price paths is futile and using a market risk adjusted single price forecast provides a justified economic basis for production scheduling while maintaining the same problem size as a deterministic production scheduling problem.

Jan 1, 2019

By R. W. M. Lai

In flotation or hydrometallurgical leaching of minerals, the cumulative metals recovery for a given process condition generally approaches a maximum value or an asymptote as the process time increases. This paper discusses the experimental methods of identifying and obtaining the asymptote of metals recovery through kinetic studies. In flotation, the kinetic asymptote of metal recovery, or ultimate recovery, is a function of grinding and collector dosage, but within a realistic variable range, is not a function of pH or temperature. However, variations in grinding, collector dosage, pH and temperature, all exert noticeable effects on flotation kinetics. Frothers generally have a minor affect on the asymptote, but have a major affect on flotation kinetics. The asymptote from batch flotation is found to be identical to that of a continuous flotation. In hydrometallurgical Leaching, the asymptote of metal recovery for a given leaching system is a function of such variables as temperature, particle size, and acid concentration.

Jan 1, 1983

By I. Weir-Jones

[Currently the cost of carrying out 'in situ' geotechnical investigation programmes or installing and operating monitoring systems at construction or mining sites is rising var." rapidly. This is primarily because of our ever increasing labour rates. As a result of this problem efforts are no,, being made develop techniques for the economical; collection of large quantities of geotechnical data relating, to such problems as done stability evaluation, the behaviour of underground openings, or 'in situ' testing procedures. The efforts to reduce the labour content. are particularly apparent in those procedures which have traditionally been manpower intensive e.g. 'in situ' permeability testing where an entire drilling crew and their associated eguipment have been on standby while testis has been carried out; or data collection in underground construction operations where much tine is typically wasted obtaining or maintaining access to instrument sites. In an attempt to illustrate one specialist consulting company's approach to the problem of reducing investigation costs, this rarer examines four recent developments in the field of geotechnical investigation and monitoring which have come about during the last two Years as a result of cur research and development programme. Although these techniques and devices have been developed for specific projects, they all have broad applications in the geotechnical field and they are indicative of the direction in which this company feels developments will take place.]

Jan 1, 1975

By L. S. McNickle

[Commonly accepted maintenance methods are being outdated by the rapid acceptance and use of more complicated hydraulic circuitry on modern mining equipment. It is no longer adequate to use the maintenance program to merely repair or sustain equipment operation. Ever increasing operating costs place a huge premium on lost production time. It has, therefore, placed the maintenance programs in the position of being required to alleviate equipment malfunctions on production shifts and still attain the maximum unit life from each component part.]

Jan 1, 1961

By E. F. Paski

Geological materials are likely the most complex and challenging substances to quantitate by ICPOES (inductively coupled plasma optical emission spectroscopy). For complex materials having widely varying compositions, spectral overlap interferences govern detection and quantitation limits attained by ICPOES based analytical methods.

Jan 1, 1993

By Jr. Koch

Since 1882, world zinc production has increased. In contrast, United States zinc production rose until about 1915, but since then has remained nearly constant, with a slight tendency to decrease. Production from the Tri-State district, the largest early source of zinc in the United States, has gone down steadily; this decline has been balanced by a growth in the rate of other districts. These changes in United States production are due to economic, not geological, factors. Recent exploration has located large mineable ore bodies; additional deposits will undoubtedly be found in the strata-bound carbonate rock and volcanogenic environments. A statistical analysis of the exploration effort in the Middle Tennessee district indicates that new discoveries can be expected there. Thus, the United States is in an early stage of the production cycle for zinc. Of major mining districts in the United States, only the Tri-State is exhausted under current economic conditions; large zinc resources of low-grade material, which would repay mining at higher prices or improved technology, are known to exist in that district.

Jan 1, 1980

By R. Bernard

This paper will discuss innovative strategies that combine the capabilities of an Enterprise Asset Management (EAM) solution, sometimes referred to as a Computerized Maintenance Management System (CMMS) and E-Commerce solutions. Strategies discussed include solutions that minimizes the costs of operations through maximized equipment productivity and availability. Thusly, achieving the ultimate goal of keeping the cost per production unit as low as possible.

Jan 1, 2001

By I. W. Farmer, R. E. Finky

Design of structures in rock based on ultimate limit states or strength criteria is unrealistic. The fracture process which inevitably occurs in rock around an underground structure is an energy release phenomenon. The development of fractures and associated displacements around a structure may therefore be more logically described using strain energy concepts and design may sensibly be based on serviceability limit states.

Jan 1, 1986

By K. H. Al-Rawahy

Appreciation and awareness of the unique nature of mineral investment and ultimate development of a mine are crucial in promoting sustainable development. Special characteristics of mineral development include high capital intensive, long pre-production period, high risk, and the unavoidable ?economic? depletion. This paper examines ways to integrate these unique attributes of the mineral industry into the educational process, so that a properly advised and knowledgeable culture in terms of a sustainable mineral industry can be developed. Specific approaches are investigated in order to achieve this objective. These include a stochastic evaluation of a mineral investment proposal, adding a premium to the cost of capital that is used for valuation process, and internalizing incidental costs to the private cost function, thereby realizing the true (vs. apparent) marginal social cost of the proposed development. Undoubtedly, a total evaluation of any mineral project that accounts for both tangible and intangible parameters will contribute to sustainable development objectives. By incorporating the practical application of apparent theoretical topics such as risk, probability, and externality, and their relevance and impact on mineral lifecycle (prospecting, exploration, development, exploitation, use, and ultimate disposal) into the educational process, it is hoped that a generation of technocrats and decision makers that are familiar with and concerned about sustainable development will emerge.

Jan 1, 2007