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By Qing Wang, Xiaochuan Xu, Jianping Liu, Xiaowei Gu, Qingyu Zhu

"The ecological costs related to the various optimized production schemes were calculated based on the designed ultimate pit. Moreover, the influence of the ecological costs on the selection of production schemes was discussed. In one designed pit, a series of geologically optimum pushbacks with sufficiently small increment were produced using the floating cone method founded on the principle of the highest metal content. Then all the pushbacks were reordered by the dynamic network diagram. The production scheme with the maximum NPV route was considered as the optimum one. The ecological impacts produced by mining were quantified and the ecological cost calculation models, which contain the direct eco-value loss, the indirect eco-value loss, the eco-restoration cost and the carbon emission cost were proposed. In one big open pit mine case, various production schemes were optimized and the one with maximum NPV was selected without taking into account the eco-costs. The scheme with the maximum comprehensive profit was obtained by calculating the eco-cost of each scheme. The results showed that the best scheme considered with the eco-cost was not the scheme with the maximum NPV. Therefore, the eco-cost presents the effect on the selection of the best production scheme.Introduction Optimizing production scheme is to determine the mining quantities of ore and rock, the pushing position of stope each year, and maximize the NPV of mine. In the theory, production scheming optimization has gone through trial and error (Pana and Carlson 1966), linear programming method (Johnson 1968), mixed integer programming (Gershon 1983), integer mapping (Kim and Cai 1990), dynamic programming et al (Gu et al 2014). In recent years, the study on production scheduling optimization has been focused on two aspects. On the one hand, the study is to solve the investment risk caused by the uncertainties of economic and geological environment (Ramazan and Dimitrakopoulos 2013, Marcotte and Caron 2010, Lamghari and Dimitrakopoulos 2012, Godoy and Dimitrakopoulos 2004, Benndorf and Shishvan 2014). On the other hand, the emphasis of the study was on reducing the problems for the optimization algorithm, to make it more efficient and practical (Cullenbine et al 2011, Shishvan and Sattarvand 2015, Askari-Nasab et al 2011, Nasab et al 2010). However, different production schemes cause different damage of mine land and pollutant emission, thus triggering environment problem. With the improvement of people’s consciousness of environment protection, the environmental issue of mining has been attracting more and more attention."

Jan 1, 2017

By Tuncel M. Yegulalp

In this paper we revisit the well known "Ultimate Pit Limit Problem" and suggest an alternative approach for fast and efficient solution. We follow the approach originally proposed by Johnson and Barnes (1988), but utilize the "Excess Scaling Algorithm" in solving the equivalent maximum flow problem. This algorithm provides significant increases in speed and reduction in memory requirements over the well known Labeling Algorithm of Ford and Fulkerson (1956), enabling one to solve large problems with relatively small computers. We present results of a series: of benchmark tests using this approach against the well known Lerchs Grossman algorithm as well as a brief description of the new algorithm.

Jan 1, 1992

By J. Mark Richardson, Mary S. Sredanovic

The use of computerized steady-state process design balance systems has reduced engineering man-hours by as much as 80 to 1 over conventional manual balance calculations. The popularity and widespread use of such systems by the minerals industry increased dramatically in recent years, but these systems were mainly available for use on large main frame computers and lacked graphic capability. A considerable amount of engineering manpower was required to "conceptualize" a process flowsheet. After sketching the flowsheet layout, the engineer was still faced in most cases with a time-consuming reduction of his graphic concept of the problem to numerical data required by the balance program. Furthermore, output from these early systems was usually in tabular numeric form. The computer results then were transferred manually to a pictorial representation of the process. A new process design balance system has been developed which runs on a popular and inexpensive personal computer. This system combines modern Computer Aided Design (CAD) principles and the graphics capabilities of the personal computer to allow the process engineer to define a flowsheet problem while creating a process flow diagram. The system provides balance results in both pictorial and tabular form. Past, present, and potential applications of the system are discussed, and an analysis of the cost benefits derived from its use are provided.

Jan 1, 1985

By K. L. Johnson

Networks of monitoring wells were established prior to mining at four longwall mine sites in the Appalachians to monitor the effect of mining on water levels, water quality and well yield. Two of the sites were located in stream valleys and the other two sites were located on hilltops. The depth to the mined seam ranged from 500-850 feet with the deeper cover being associated with the hilltop sites. Maximum declines in groundwater levels during and after mining were an order of magnitude less in the stream valley aquifers than in the hilltop aquifers. However, water levels in hilltop wells located outside the area immediately above the panel were unaffected. Water quality changes in wells as a result of longwall mining were negligible at all four sites. Increases in aquifer transmissivity and well yield were much more pronounced in the stream valley aquifers than in the hilltop aquifers. The significantly larger recharge area for the stream valley aquifers than that for the hilltop aquifers may partially account for the differing responses of these two classes of aquifers to longwall mining. These observations appear to be consistent with the stress-relief fracture model for Appalachian Plateau groundwater hydrology proposed by Wyrick and Borchers in 1981.

Jan 1, 1986

By Carl E. Nelson

Shallow epithermal stockworks hosted by maar eruption craters contain over ninety percent of the bulk mineable gold identified to date in the Circum-Caribbean region. Pueblo Viejo (Dominican Republic) and Santa Rosa (Panama) contain combined gold reserves of over 600 tonnes. Bulk mineable gold deposits are also being discovered in and around veins that were formerly mined underground. Bellavista, El Recio and San Martin (Costa Rica) contain combined announced gold reserves of over 50 tonnes. Representative rock suites collected at 8 bulk mineable gold deposits include 291 samples of veins and vein stockworks, hydrothermal eruption breccias, sinter, variably altered host, unaltered host, nearby intrusive rocks and basement. Analyses completed to date show that Circum-Caribbean epithermal ores are enriched in arsenic, mercury and antimony as well as gold and silver. Exploration efforts in the region naturally focus on districts with past production. However, an order of magnitude more bulk mineable gold has been discovered in shallow epithermal stockworks outside of the old bonanza vein camps. Exploration guides include basal island arc volcanic sequences, hydrothermal and hydrovolcanic (maar) eruption breccias, thinly-bedded carbonaceous maar sediments, and hot spring-related silicification and argillic alteration.

Jan 1, 1990

By J. W. Merks

Spreadsheet software is used to convert test results for drill core samples into borehole statistics such as volumes and masses of in-situ ore, metal contents and variances of metal contents. The properties of variances and the sampling variogram play a pivotal role, The additive of property of variances gives a sound scientific basis to the calculation of confidence limits for metal contents and grades as a measure of the risks associated with estimating reserves and resources.

Jan 1, 2000

By Andrzej Wala, Henry P. Cole, Perry David Passaro

Cognitive representations and misconceptions of flow through circuits is an area which has received little attention from science educators, cognitive psychologists, or accident investigators. Misconceptions are also called Aristotelian thinking. They involve a person using primitive unscientific ways of reasoning to make decisions about events (Piaget, 1929; Nussbaum & Novick, 1982; McCloskey, 1983). The use of such primitive concepts leads to errors in reasoning about scientific and technical problems. The existence of misconceptions is well documented among children, adolescents, and adults involved in learning science concepts (Piaget, 1929; Cole & Raven, 1969; Clement, 1982; Mistrell, 1982; McDermott, 1984; Richardson, 1987). Concepts of flow through circuits are important because miners' conceptual errors about these aspects may be, in part, responsible for two fatal mine disasters. On at least two separate occasions, methane gas explosions occurred in underground mines when separate ventilation systems were connected (Elam, Fuller, Carter, Cavanaugh, Fesak & Painter, 1983; Fesak & Cavanaugh, 1984). A review of these disasters indicates that conceptual errors made by miners may have resulted in the accidents (Cole, Wala, Haley, & Vaught, 1987). In this study, co-author Andrzej Wala, stated that his research had "identified conceptual errors that may have caused the miners in these disasters to make fatal mistakes" (Cole et al. 1987), p. 167. Further exploration of these conceptual errors by Wala has led to the hypothesis that misconceptions of basic aspects of flow distribution changes in mine ventilation circuits, are at least, in part, responsible for some mine disasters caused by errors in ventilation systems (Wala & Cole, 1987). Why should these conceptual errors occur? Ausubel (1963) suggested that students come to a new area of study with their own conceptions or preconceptions about how a process operates. Furthermore, these preconceptions may be in conflict with the empirical data from the discipline. In such cases, learning becomes a process in which new concepts must displace or be re-molded from stable concepts that the student has constructed over many years (Clement, 1982). Given the existing research with misconceptions and the work of Wala and Cole (1987), it was hypothesized that experienced miners; either working miners, students of mining engineering, or professional mining engineers, harbored misconceptions about the formal or conceptual aspects of mine ventilation circuits. The misconceptions hypothesized to exist involved flow distribution changes in complex mine ventilation circuits; specifically, how does flow distribution change when a ventilation circuit pathway is altered? Given this information, the following research questions were proposed. Research Questions 1. Do experienced miners and mining engineers harbor misconceptions about mine ventilation systems? This question was addressed by: A. The administration of the Cutthrough Ventilation Arrangements (CVA) exercise that measures subjects' performance level when making decisions about major ventilation changes when connecting two mine sections;

Jan 1, 1989

By K. H. McDaniel

This paper describes the development of a Windows-based interactive mine ventilation simulation software program at the Waste Isolation Pilot Plant (WIPP). To enhance the operation of the underground ventilation system, Westinghouse Electric Corp. developed a program called WIPPVENT. While WIPPVENT includes most of the functions of the commercially available simulation program VNETPC from Mine Ventilation Services Inc. and uses the same subroutine to calculate airflow distributions, the user interface was completely rewritten as a Windows application with screen graphics. WIPPVENT is designed to interact with WIPP ventilation-monitoring systems through the sitewide central monitoring system. Data (e.g., air quantity and differential pressure) can be continuously collected from the underground ventilation remote-monitoring and control system and from the mine's weather stations (psychrometric data). Furthermore, WIPPVENT incorporates regulator characteristic curves specific to the site. The program utilizes this data to create and continuously update a real-time ventilation model. This paper discusses the design, the key features and the interactive capabilities of WIPPVENT.

Jan 1, 1997

By Steve Rule, Jose Roberto Vago, Walter de Moura

Cerro Vangaurdia Gold Mine is a joint venture between AngloGold (the operator), Perez Companc and Formicruz and is situated in the southern province of Santa Cruz, in Argentina, approximately 2,150 km south of the capital, Buenos Aires. The mine is located in a severe, semi-arid environment with very cold winters and little annual rainfall (200mm). It is an open-pit operation, mining several narrow, shallow epithermal quartz veins with . gold and silver mineralisation. Commissioning of the plant commenced in September 1998 and the first dore bar was poured towards the end of the same month. The nominal capacity of the plant is 55,000 tonnes per month, with a design capacity of 60,000 tonnes per month. Prior to finalising the design, an extensive testwork programme was undertaken at Nova Lima, in Brazil, in which all parts of the process were evaluated together on a pilot-plant scale. The process flowsheet selected at Ce1rn Vanguardia is quite novel, in that it includes milling in cyanide, as well as a cyanide recovery and recycling plant on the tailings section of the treatment plant is included. The cyanide recovery process selected was a version of the acidification - volatilization - reabsorption (AVR) process, known as Cyanisorb™. The selection of the Cyanisorb™ process in the plant design was as a direct consequence of two factors:

Jan 1, 2000

By Mauricio Brücher, Juan Camus

This article deals with open pit mine planning and a computer technology known as Direct Block Scheduling, or “DBS”. This is an emerging technology for modeling mine exploitation strategies using mixed-integer linear programming. This technique has proved to yield stronger economic results compared to the Lerchs-Grossmann (“LG”) algorithm currently used at the beginning of the mine planning process. The article briefly describes the shortcomings of current practice; then, this delves into the superior results obtained by DBS technology compared to current practice. Finally, the article argues that results achieve so far by DBS could be enhanced even further. To do this, the framework to apply this emerging technology, which is also used in current practice, should be modified to better exploit the capabilities of DBS technology. To better understand this change, an illustrated case study is presented at the end of the article.

Jun 25, 2023

By Timothy D. Gardner, Christopher Mark

Coal mines in the Illinois Basin have not engaged in pillar recovery for many decades. In large part, this is due to the exceptionally weak nature of much of the roof in the region. But, as room-and-pillar mining is conducted at greater depths, and larger pillars become necessary, recovering them becomes more attractive. Recently a western Kentucky coal mine became the first in recent times to successfully employ full pillar recovery. This paper describes the many challenges that were overcome during the process. From the beginning, the focus was on protecting the miners from roof instability, using cable bolts, mesh, mobile roof supports (MRS), and engineered final stumps. Two short test panels were extracted first, and the results were used to adjust the support pattern and mining sequence. Further adjustments were made based on subsequent experience. To date, seven panels have been recovered without a ground fall injury.

Jul 1, 2023

By S. K. Kawatra, R. A. Seitz

There is considerable variation in the types of coal flotation circuits in use in various parts of the world. For example, Russian plants frequently use scavenger flotation, while this is almost unheard of in the United States. The numerous circuit designs are intended to address specific problems in coal flotation, or to take advantage of the peculiarities of certain coal deposits. As a result, it can be difficult to decide which circuit is best for a given application. For this paper, coal flotation circuits were collected worldwide from many operating plants. These circuits include varying degrees of conditioning, and complexity ranging from simple rougher flotation to multi-stage split- stream processing. The design goals of each circuit are described, and the advantages and disadvantages of each are discussed. Extensive sampling campaigns were carried out in two plants with the most common types of coal flotation circuit (simple rougher, and rougher with deslimed feed). The performance of each plant was evaluated, and the benefits of more sophisticated processing in each case are described.

Jan 1, 1993

By I. Casasbuenas, K. A. Nguyen, E. I. Ngoma, H. Kim, D. Borja, J. H. Park, R. A. Silva, S. Choi

"This study aimed to determine the optimum operating parameters of a continuous bioleaching system to leach arsenic (As) from mine tailings using a mixed mesophilic bacterial culture. The microbial consortium, previously adapted for effective growth at high pulp density and metal concentrations, was mainly composed of Leptospirillum ferriphilum, and Acidithiobacillus caldus. The mine tailings, collected from the Janggun mine (South Korea) contained 11% (w/w) of As. The tests were performed in a laboratory-scale unit composed of three reactors connected in series following a cascade configuration. Agitation speed, air supply, solid concentration, residence time and temperature were systematically optimized by assessing the leaching activity. Several parameters were monitored on a daily basis, including the As released into solution, iron oxidation rates, pH, cell concentration, dissolved oxygen and redox potential. Overall, improvement of oxygen transfer, by optimizing the agitation speed and air supply, presented the most tangible impact on the leaching performance. The highest As leaching efficiency observed in this study was 82%, which supports the feasibility of the process. INTRODUCTION Worldwide, around of 65 billion tons of mine tailings are produced every year (Jones & Boger, 2012). These materials comprise the waste minerals produced after ore beneficiation. Mine tailings usually contain heavy metals (e.g., Cobalt (Co), Lead (Pb), Zinc (Zn) and Arsenic (As) (Falagán, Grail, & Johnson, 2016; Nguyen, Lee, Park, & Lee, 2014). The exposure of these materials to the environment can produce serious health damage and environmental degradation (Martin, Dowling, Pearce, Sillitoe, & Florentine, 2014). Mine tailings management represents a major issue in South Korea. There are more than 1,000 abandoned mines containing stockpiled mine tailings within the territory (Choi, Park, Hong, Park, & Kim, 2013; Kim, Kim, Ahn, Ko, & Lee, 2005; Lee, Lee, & Kim, 1998). These tailings comprise high concentration of arsenic. Therefore, the Korean Government has directed its efforts to developing eco-friendly technologies, for the arsenic detoxification of mine tailings Continuous bioleaching is explored as a remediation technology (Borja et al., 2016). The present study aimed to develop a mixed mesophilic bacterial culture for optimal growth at high metal and solid concentration; and optimize the operating conditions of a continuous bioleaching unit. This investigation forms part of a larger study aimed to develop a bioleaching technique to treat Janggun mine tailings (Borja et al., 2017; Ngoma et al., 2017)."

Jan 1, 2018

By H. Copur

Roadheaders offer a unique capability and flexibility for the excavation of soft to medium strength rock formations, therefore, are very attractive in underground mining and tunneling operations. This paper reviews the importance, technological developments and application limits of roadheaders based on the case histories, which are compiled in a database including different roadheaders in various geological conditions. The paper also discusses the database and empirical performance prediction studies regarding instantaneous cutting rates and bit consumption rates.

Jan 1, 1998

By L. Berwick, A. Karunanayake, D. Skutt, H. Heath, J. Wang

Thallium (Tl) is a highly toxic heavy metal, soluble over a wide pH range. Tl levels may exceed discharge limits in mining-influenced water associated with processing gold, lead, cadmium, zinc, and copper ores. In this work, the effect of sodium permanganate (CARUSOL® C liquid permanganate) on Tl removal from mining wastewater was studied. Factors influencing Tl removal, namely permanganate dosage/demand, coagulant and flocculant use, order of chemical addition, and co-existing metal ions were examined. The results show that permanganate addition is very effective at removing Tl to below target limits and can provide a unique solution for improving wastewater quality and optimizing overall treatment costs. In addition, several on-line monitoring techniques were evaluated for process optimization. The Hach DPD Free Chlorine method was optimal, allowing plant operators to rapidly and easily spot check effluent samples for excess permanganate dose.

Mar 2, 2022

By Wai Wu, C. Haycocks

The majority of Appalachian coal deposits lie in a multi-seam environment. Historically, the decision to extract a particular seam has been based on ease of access, ownership and economics rather than ground control considerations. As mining progresses and seams are being mined out, it is increasingly common to find working and abandoned mines in close vertical proximity to each other. Such contiguous operations can produce both positive and negative ground control situations in neighboring seams. These ground control problems, defined as interaction problems, are frequently reported, and their severity can range from minor roof problems that may require no additional support to complete loss of a large section of coal reserves (Stemple, 1955; Peng & Chandra, 1980; Haycocks & Karmis, 1983; Su et al, 1984). As a consequence, interaction problems are of growing concern to the Appalachian underground coal industry. Although interaction problems in multi-seam mining have been recognized for many years and many investigations have been conducted to study the problems, the ground control principles involved in their development are only partially understood. Previous research has identified four interaction mechanisms: pillar load transfer, innerburden shearing, arching effects and upper seam subsidence (Haycocks et al, 1982; Haycocks & Karmis, 1983). Pillar load transfer mechanisms and innerburden shearing have been successfuly used to explain interaction phenomena associated with undermining operations, while arching and subsidence have been used to assess problems during overmining. In addition, interaction-controlling factors such as cover, innerburden and seam thicknesses, extraction percentages on both seams, time delay between operations on two seams, and characteristics of innerburden rock have been identified and utilized in evaluation of interaction effects (Haycocks & Karmis, 1983; Webster et a1.,1984). As an example, Figure 1 shows the relation of innerburden layering and thickness to interaction on the lower seam. The combination of such theoretical work and the analysis of case study information has made it possible to determine, with a certain degree of confidence, the interaction damage in undermining conditions. The results of such an approach have been sufficiently successful and complete to be incorporated into a software package to assist field engineers in estimating potential interaction effects when undermining a previously mined upper seam (Grenoble et al, 1984; Grenoble & Haycocks, 1985; Grenoble et al, 1985). Although the conventional finite element and photoelastic modeling techniques have been

Jan 1, 1986

By Al. Valero, A. Domínguez

This paper appraises the energy requirements for mineral production through an exergy approach taking into account the long-term decline in ore grades. In this context, the exergy required for restoring resources from the dispersed state of the so called Crepuscular Earth into the physical and chemical conditions in which it was delivered by the ecosystems in light of the available technology, is known as exergy cost. The exergy cost is the point of reference in order to evaluate in a single variable, characteristics such as composition, concentration (ore grade) and the state of technology. The ratio between the exergy cost and the minimum thermodynamic cost required to accomplish the same process is called unit exergy cost and provides a measure of the irreversibility of the analyzed processes. Otherwise, the ore grade is one of the main issues which affects directly the costs associated with mining the ore. Hence, the unit exergy costs to produce minerals from progressively lower ores grades by the current technology is analyzed. The unit exergy cost curves are presented for some important minerals such as aluminium, chromium, cobalt, copper, gold, lead, manganese, nickel and zinc, in order to know the trend when the ore grade decreases.

Jan 1, 2011

Bismuth, "the green metal," has become an important substitute for lead. The uranium industry was never really dead, anti-nuclear activists just wanted the world to think it was. And diamonds are fast becoming a miner's best friend. These commodities and others were discussed in May 1997 at the 47th Annual Minerals Processing Division meeting, held at the Broadmoor resort in Colorado Springs, CO. The meeting was put on by the SME Colorado subsection and was attended by about 115 people. In addition to the above three commodities, attendees learned more about the state of the copper industry, as well as lead and zinc and gold and silver. The program also included discussions of molybdenum, platinum and project financing. The following is a summary of some of the presentations.

Jan 1, 1997

By Ryan Lindmark, Guoxing Gu, Zhenghe Xu, Jacob H. Masllyah

Induction time is often referred to the time required to form a stable three-phase contact between a gas bubble and a flat or droplet surface in a liquid medium. It can be used to quantify the attachment process in aflotation system. Various techniques have been developed to measure this important parameter. Due to its importance in flotation systems and other processes, significant advances in refining the induction time measurement techniques have recently been made. This paper summarizes these recent advances and describes a novel method developed to monitor bubble attachment to a pendant bitumen drop or bitumen-coated flat surface. This visualization-based method offers a higher sensitivity and accuracy than the previously developed apparatuses in the induction time measurement. As an example, the induction time for oxygen bubble-bitumen attachment was measured at a fixed bubble size as a function of temperature in two different aqueous solutions. The results showed that higher process temperature is favorable for oxygen bubble-bitumen attachment and hence bitumen flotation. Addition of calcium to the aqueous solution slightly decreased induction time.

Jan 1, 2005

The estimation of local recoveries, such as the local recovered tonnage of ore and its corresponding grade at a given cutoff grade, is an important problem in a selective mining operation. Multigaussian kriging provides a simple solution to this specific problem. The solution is also complete in the sense that local recoveries are estimated together with their estimation variances. It is thus possible to assess confidence limit intervals on the estimated recoveries. Multigaussian kriging has been applied to the Jerritt Canyon deposit in a most realistic situation. The various steps of the estimation procedure are presented in detail and the potential of the method is demonstrated in view of the results. The obtained results show that the estimated recoveries are in good agreement with the actual recoveries and the actual estimation errors are correctly predicted by the estimation variances. Multigaussian kriging thus appears as a useful and fully operationable tool for the mining industry.

Jan 1, 1986