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By A. Halim, A. Martikainen, S. GYAMFI

This paper outlines a unique case of the development of strategies to reduce ventilation and heating costs in Konsuln iron ore mine in northern Sweden. The mine, located just south of Luossavaara-Kiirunavaara Aktiebolag’s Kiruna iron ore mine, was developed as a test mine from 2018-2020 for the Sustainable Underground Mining (SUM) project. Besides functioning as a test mine, Konsuln also contributes to ore production. The existing mine ventilation system was designed for the current production rate of 0.8 million tons per annum (Mtpa). There is a plan to increase this rate to between 1.8 and 2.0 Mtpa.

Dec 23, 2021

By C. Bailey Williams

Aragonite "sand," an oolitic lime-stone, is distributed throughout the Bahamas on the Grand Bahama Bank, adjacent to Southeast Florida. Bahamian deposits hold 75-100 billion tons of recoverable Aragonite. Aragonite's precipitation from seawater over 700 years ago assures low contaminates, making it a pure material for such industries as cement, glass, etc. A 90-acre, man-made production island was built south of Bimini, adjacent to ocean shipping channels mining is by cutterhead, suction dredge, dewatering, and stockpiling for further drainage and shipping. Aragonite is transferred to the U. S. East and Gulf Coasts via bulk carriers to points of sale.

Jan 1, 1978

By W. P. Barnett

In 1988, the U.S. Department of Energy's Pittsburgh Energy Technology Center identified three coal cleaning options for achieving flexible environmental control strategies aimed at reducing energy-related SO2 emissions. These are selective agglomeration, advanced froth flotation, and advanced cycloning. Each technology relies on maximum liberation of pyrite and other mineral matter through feed coal comminution to fine and ultrafine sizes. Research projects designed to expeditiously develop each of these technologies to the point of commercial viability were initiated. This paper will present the status of these projects and the application potential of each technology to coal beneficiation.

Jan 1, 1992

By J. J. Gusek

Several final pits in the Seneca No. 1 Surface Coal Mine were abandoned in the 1960's without being reclaimed. In addition, a progressive landslide aggravated by the abandoned mine land conditions was threatening a county road and private property. An AML-funded project to stabilize the landslide and reclaim the final pits was completed in 1986 for the Colorado Division of Mines and Geology (formerly Colorado Mine Land Reclamation Division). The site was visited after ten growing seasons. The land is stable and the vegetation re-establishment is strong. Volunteer native plant species are now invading the reclaimed sites.

Jan 1, 1997

By R. A. Ynchausti

In January 1993, Pyramid Resources began implementation of a supervisory expert control system at a U.S Cu concentrator. The objective of this control system was to improve plant profitability through unit operation optimization and integration. This paper documents the key aspects of the project, including: economic and associated benefits, system architecture, concepts of implementation, process control strategies, practical aspects of implementation and conclusions. The implementation of expert control at this concentrator has resulted in an estimated benefit of $50,500 per day. This is a net result of improved tonnage, reduced reagent consumption, improved concentrate grade and reduced energy per ton produced.

Jan 1, 1995

By Mike Rhodes, Paul Miller, John W. Neale, Vishal Deeplaul, Barrie Hancock, Tony Pinches

The Beaconsfield underground gold mine is one of only a few new Australian gold projects to come into operation in the current climate of low gold prices. Up to 200,000 tonnes per annum of Tasmania Reef ore will be mined and processed over a minimum eight-year life to a depth of 900 metres below surface. The Tasmania Reef is a gold-bearing quartz-carbonate-sulphide vein occupying an old fault structure which transgresses a series of sedimentary beds. The sulphides are predominantly pyrite with lesser arsenopyrite, and also minor copper as chalcopyrite. Drilling to date below this level clearly indicates that the high-grade orebody is open at depth and that the mine life should be extended significantly over time. Since redevelopment of Beaconsfield mine began in the 1980's, extensive exploration has identified a resource of 1.5 million tonnes within a 450 vertical metre zone beneath the old workings, which extended more than 450 metres below the surface. Installation of an 800 litre per second capacity pump station 180 metres below the surface has been critical in overcoming one of the major hurdles experienced during previous operations in the early 1900's. A multi-stage development program, designed to bring the mine into full production, and incorporating construction of the on-site gold treatment plant incorporating bacterial oxidation, has now been completed. Prior to execution of a detailed engineering design of the Mintek-BacTech bacterial oxidation process, a programme of bacterial oxidation testwork was completed to provide a basis for fixing the process design criteria. A flow diagram of the Beaconsfield treatment plant is shown in Figure l. It comprises:

Jan 1, 2000

By V. B. Achanti, A. W. Khair

Developing a laboratory procedure for the determination of coal-seam compressive strength has been a subject of discussion for many decades, and the reliability of laboratory determinations is often the subject of debate. A coal seam’s characteristics, the method of sample collection, the specimen preparation method and the testing procedure can often result in drastic variations in the test results. In this paper, the development of a laboratory testing procedure for the determination of coal-seam compressive strength is presented. Two samples that were collected from different coal seams were tested in this study. First, the inherent characteristics, i.e., coal structure. Hardgrove grindability index (HGI), Slake durability index, proximate analysis and mechanical properties (Young's modules and Poisson's ratio), of each coal were determined. The results were used to categorize the coal scams in terms of the characteristics liable to produce variable strength data in typical laboratory tests. Second, two commonly used laboratory specimen shapes, cylindrical and cubical, were tested to determine which shape produced the most reproducible strength values. Third, four loading rates within the static testing range, i.e., 0.007, 0.07, 0.34 and 0.7 MPa/s (1.0, 10, 50 and 100 psi/sec), were used to determine the ideal loading rate. Finally, the number of test samples required to produce strength data within the acceptable standard deviation, considering coal seam characteristics, were established. Background Laboratory testing of coal specimens for the determination of seam compressive strength has been a subject of discussion since the early 1900s. Many researchers have tested coal specimens to estimate coal-seam compressive strength for use in pillar design to insure the safe operation of [ ] mines (Unrug et al., 1986; and Hirt et al.. 1992). Yet, there is a lack of a universal procedure, and, no matter which approach is used, it becomes the subject of intensive debate. A great deal of work has been performed on the subject, and there is much information available in the literature. Some of this work concerns quantifying the influence of specimen shape and size on compressive strength (Bieniawski. 1968: Barron et al.. 1992: Khair and Xu 1994; and Khair 1994). As indicted in the literature, coal is a heterogeneous material, consisting of discontinuities such as cleats and bedding planes, which are likely to produce variable strength results (Holland, 1964; Unrug et al., 1986). Some of the prominent issues that influence the determination of coal-seam compressive strength in the laboratory are: •the collection of a representative sample from a coal seam; •the geometry, i.e., shape and size of the specimens to be prepared and tested: •the loading rate at which the specimens are to be tested:

Jan 1, 1997

By C. O. Petter

This paper, in its first part, compares the profile and economic weight in the extraction of industrial minerals and aggregates to the so called conventional mining activities (metals, coal, gas and oil extraction) in Brazil. In its second part, a descriptive analysis of the present situation of the education in Brazil is made, emphasizing the graduation and post-graduation formation especially in engineering. The curricular structure of the schools that prepare the mining workforce is discussed and the presence of specific subjects in industrial minerals is evaluated. Finally, considerations are made on the actions being taken in the main universities and companies, aiming to improve the formation of the specialized workforce. The Brazilian mining production, comparing 2010 to 2011 showed an expansion of more than 3% (IBGE, 2012). Not bad, but nothing to do with the 13% growth between 2010 and 2009 (influenced by a recovery effect from the 2008 commodities? nightmare). The commodities that had a rising behavior were titanium, gypsum, nickel, graphite, bauxite, phosphate, chrome and chrysotile. All of them were eclipsed by the impressive growth of iron ore production. Some decreases could be noticed, eg. in zinc, kaolin, magnesite and salt production (DNPM, 2012). In fact, the mining activities followed the positive growth of the country these last 5 years. The commercial balance (exports against imports) was not spectacular (positive in US$ 30 billion in 2010). It is important to notice that the mineral commodities balance was US$ 35 billion, representing 27.4% of the total exports and 15.6% of the total imports of Brazil (DNPM, 2012). In this positive environment, the workforce in Brazil showed progress in number of formal jobs and average revenues.

Feb 23, 2014

By Jurij Karlovšek, Wolfgang Angerer, Vojtech Ernst Gall, Jacob Grasmick

The International Tunneling Association (ITA) Working Group (WG) 22 “Information Modelling in Tunneling” has developed a guideline for the implementation of Building Information Modeling (BIM) concepts for Bored Tunneling Projects. The guideline primarily covers the use of BIM during the conceptual and delivery phases of a project. It provides Owners with an introduction to BIM, an overview of the current capabilities of BIM, and a guide for implementation for a Bored Tunnel. The document will be officially published at the World Tunnel Congress (WTC) in Copenhagen in 2022. This paper describes the need for the guideline and provides a preview of its contents.

Dec 1, 2022

By Stefan Medel

As a pioneer Herrenknecht started in 2018 to automate the production of tunnel lining segments. Since then, many automation processes became state of the art. Robots cleaning and oiling the moulds, hydraulic units opening and closing them fully independently. Artificial Intelligence (AI) controls the works and ensures the quality requirements. Data management has become a massive tool from a simple data collector towards a control and optimization tool. Sensors controlling concrete maturity and supporting the precast team to optimize the concrete mix. These state of the art and new innovations will be presented in this paper.

Jun 23, 2024

By Frank G. Horino, V. E. Hooker

INTRODUCTION The determination and use of mechanical properties of rock in engineering and rock mechanics are rapidly developing. Many of these properties are determined on intact rock specimens; thus, their application and repre¬sentation of rock mass properties may be limited. How¬ever, relative information often provides useful guidance in the solution to mine design and stability problems. Summarized in this chapter are some of the stan¬dardized techniques and procedures currently used to obtain these mechanical properties. Typical applications of the use of these properties are also presented. Stan¬dardized techniques include those advanced by the American Society of Testing and Materials (ASTM), International Society of Rock Mechanics (ISRM), US Bureau of Mines (USBM), Canadian Dept. of Mines and Technical Surveys, South African Institute of Min¬ing and Metallurgy, and other individual investigators. Information on the mechanical properties of rock and the behavior of the rock under a given system of stresses represents a necessary part of the information for rational engineering design for any given mining op¬eration. The mining method, the type and extent of sup¬port, the extraction ratio, the overall dimensions of the mine, and the orientation of the rooms and pillars are all decisions that are influenced by the mechanical prop¬erties of the ore, roof, and floor material under various stress systems and the magnitude and direction of the in situ stresses (Hooker, Bickel, and Aggson, 1972). Initial mechanical property information regarding a structure or mine property is generally obtained by two basic techniques: (1) static and dynamic property tests are conducted on intact and fractured rock specimens of exploratory drill core, and (2) dynamic properties are obtained by borehole logging techniques. When mining access becomes available, and as the mining horizon is expanded, additional information can be ob¬tained to verify preliminary mine design values. This chapter presents some of the standardized tech¬niques and equipment currently used in obtaining me¬chanical property data in the laboratory. The properties considered are: (1) uniaxial compressive strength of intact rock core specimens, (2) uniaxial compressive strength of rock cores containing planes of weakness, (3) triaxial compressive strength of intact rock core specimens, (4) triaxial compressive strength of cores with a plane of weakness, (5) Young's modulus, (6) Poisson's ratio, (7) density or apparent specific gravity, (8) modulus of rupture, (9) indirect tensile strength, and (10) creep characteristics. Where possible, an at¬tempt will be made to evaluate each property measure¬ment in relation to the problems of rock mechanics and application of results. TEST SPECIMENS The selection and care of drill core for laboratory testing require some consideration. It is recognized that laboratory-determined properties are not necessarily rep¬resentative of an in situ rock mass property. However, relative information between beds or zones of interest is still valuable information in selecting mining horizons and preliminary design criteria. To provide statistical data the number of drill core samples selected to repre¬sent each of the areas of interest should be from a mini¬mum of three to a maximum of ten test specimens. A judgment must also be made on site as to whether the recovered drill core should be wrapped and sealed in plastic to preserve moisture. On the one hand investiga¬tions of air-dried and saturated specimens have shown that moisture significantly affects the elastic properties and strengths of many rock materials (Obert, Windes, and Duvall, 1946; Colback and Wiid, 1965); on the other hand it is apparent that most core drilling is done with water which may saturate the specimen to a greater extent than in the in-situ condition. Whether or not the decision is made to retain the moisture, the core should be delivered to the laboratory as soon as possible after recovery for subsequent specimen preparation and testing. Specifications Shape: The shape of the specimens influences lab¬oratory testing in two ways: (1) time and cost of sam¬ple preparation and (2) strength of the material. Cy¬lindrical specimens of drill core are by far the least time-consuming to prepare for static or dynamic labora¬tory testing. In addition, the cylindrical shape lends it¬self to a more uniform stress distribution throughout the sample than other shapes, such as rectangles and hexa¬gons. The compressive strengths of various shapes have been studied (Grosvenor, 1963, and Price, 1960), and results indicate that the cylindrical specimens usually provide the highest strength for a given height-diameter ratio. However, reduction in strength from a cylindrical shape to a rectangular in situ pillar is not regarded as significant in relation to other considerations such as planes of weakness in a pillar or safety factors in the design process. Length-Diameter Ratio: The length-to-diameter ra¬tio, LID, has a significant effect on the compressive strength. Various recommendations have been made to use standard LID ratios ranging from 2 to 2.5 to 3 (ASTM, 1975c; ISRM, 1972). However, past work by others such as Obert, Windes, and Duvall (1946) has shown that excellent results can be obtained using LID ratios from 2 > (LID) > >/s. In selecting an LID ratio for testing, one should keep in mind the amount of material available for testing. In many instances, this may be limited. Thus, a shorter specimen such as 1: 1 LID may be necessary to provide enough test data for statistical analysis of results. Sec¬ond, it may be desirable to obtain elastic constants dur¬ing the test. This generally requires instrumentation such as linear variable differential transformers (LVDTs) or strain gages near the center of the specimen. In this case, an LID of 2.5 or 3 is desirable so that the instru

Jan 1, 1982

By Michael Forbes, Rick Jeuken

The challenge of managing geological uncertainty in mine planning is central to optimizing resource extraction while minimizing risks and costs. This paper introduces a novel approach to coal mine planning by integrating chance-constrained programming to address the uncertainty inherent in mining operations. The main takeaway from this work is the demonstration that focusing on reducing the variance of high-quality coal blocks, rather than low-quality ones, can lead to better blending outcomes, higher profitability and more efficient resource utilization. The study presents a case study of a coal mining operation, using chance-constrained programming to manage the uncertainty surrounding coal property predictions, specifically the predicted coke strength after reaction (CSR).

Jan 1, 2025

By M. B. Haggerty, Joe Welna

The Minnesota Department of Transportation is constructing a stormwater storage facility (SSF) along Interstate 35W (I35W) south of downtown Minneapolis, MN. The project will provide storm surge capacity reducing the frequency with which major precipitation events result in flooding of I35W. The design consists of six, 42-foot diameter, 90-foot deep, adjacent underground shafts providing 14.7-acre feet of storage. Construction challenges include high groundwater with variable glacial outwash deposits. Constructability and ground variability were managed using construction manager general contractor (CMGC) project delivery. CMGC provides an environment for collaboration and innovation starting in the design phase and carrying through construction. This paper provides an overview of key efficiencies and collaboration examples implemented on the I35WSSF project which were aided by CMGC delivery.

Jun 13, 2023

By Ross Goodman, Jean-Luc des Rivières

The Ohio River Tunnel Project encountered multiple unexpected geotechnical challenges which, continuing to develop over time, hampered excavation completion and impacted the cast-in-place final lining technique and work execution sequence for the entire project. The continued degradation of the excavated hard rock tunnel conditions led to a unique, dynamic, geologic setting that forced the project to innovate new and adaptable measures allowing for a conventional cast-in-place liner to be completed in a safe and timely manner and minimize delay.

Jun 13, 2023

By Russell L. Dahl

In a continuing effort to improve plant efficiency, United States Steel's Atlantic City Ore Operations completed the rubber lining of its balling drums in late 1982. This resulted in benefits of reduced bentonite consumption, reduced maintenance costs, improved production rates, and lower power consumption. These advantages far outweigh the disadvantages of increased oversize production and increased surging on the roll screen sizing devices. Certain operating characteristics and variables are discussed herein.

Jan 1, 1983

By John Murray, Daniel Ebin, Robert Gould

The Atlanta Plane Train project at Hartsfield-Jackson Atlanta International Airport employed the progressive design-build approach. This provided opportunities for collaboration between the design-builder, design engineer, and owner and the implementation of innovative design and construction approaches. The innovations have reduced risks, allowed for adjustments during design to accommodate new challenges, and provided open-book cost and schedule evaluations. The progressive design-build approach has also allowed for pricing of work to occur in phases—capturing the design/construction challenges as the project evolves and when they are more clearly defined. While this has allowed for pricing to be performed with better project understanding and therefore less contingency, the associated time frame for approvals has required careful consideration to avoid impacts to the schedule. This paper discusses the benefits and challenges of the progressive design-build approach.

Dec 1, 2022

By Brian Young, Ben Pantony

Interferometric Synthetic Aperture Radar (InSAR) has played an integral role in many large scale tunneling projects globally. Until recently, it has been regarded as a complementary monitoring tool. On the Los Angeles Metro Purple Line Phase 1, InSAR was proposed as a primary means to replace weekly and bi-weekly surface monitoring requirements on surrounding critical infrastructure. This paper will summarize the statistical analysis approach engaged in order to compare and contrast a year of historical InSAR data to known geodetic survey data, in order to utilize InSAR as an operational monitoring tool on this project.

Jun 13, 2021

By Eileen Ashworth

Introduction A study was completed that investigated the enrollment in mining engineering programs in 24 universities and colleges. All programs considered in the study award four-year bachelor of science degrees in mining engineering. They also provide all the engineers for the mining industry and a large portion of the geotechnical engineers working on environmental problems, storage of hazardous waste, civic, and Federal government underground projects. The numbers used as the base for the study are those reported by each program to SME-AIME and published yearly (SME, 1986). Data for the study came from the period 1975-1985. Also, since some programs include students in related disciplines and special categories, such as cooperative students, a few inaccuracies were unavoidable. A 23-page document has been prepared that reports on the overall picture of current enrollment, the trends, and discusses the results, perceived effects, and what can, or should, be done. There has been an obvious, and dramatic decrease in total undergraduate enrollment since the late 1970s. In 1978, 3117 students were enrolled. In the 1985 fall semester, enrollment was 1022, less than one-third. There were 485 seniors, 265 juniors, 147 sophomores, and 125 freshmen. The downward trend in total enrollment is likely to continue for at least another two years. Class size The catastrophic drop in enrollment is shared by all programs across the country. It does not discriminate between types of programs, coal or hard rock mining, or location. In general, 1985's enrollment is about 30% of whatever the maximum enrollment was in any program, though this varies from the teens to 50%. The latter percentage occurs only for some programs with special circumstances, particularly new programs not well established in the late 1970s. The beginning of the decline in enrollment has occurred at slightly different times as affected by the demise of each program's local industry. The numbers in each class produced from a specific freshmen year (Fig. 1) are worthy of comment. The dramatic drop in enrollment for all classes after 1982 is clearly demonstrated. The timing coincides with the general downturn in the mining industry, when many employed engineers were laid off and new graduates could not find jobs. Also, significantly fewer students are being attracted to mining programs as freshmen. The number of seniors shown seems inappropriate. Where did so many seniors come from and why are so few graduates produced? There is an increasing trend for students to take four-and-a-half or five years to graduate. Therefore, they are counted twice, once when they are first classed as seniors and again the following year. Some students purposely delay graduation to obtain more summer work experience and take additional courses. They believe that this gives them a better

Jan 8, 1986

By Brad Grothen

What is the most economical way of tunneling in mixed ground that may experience high pressures? Non-continuously pressurized, mixed ground Tunnel Boring Machines (TBMs) are being utilized to deal with a wide range of geology. Continuous improvements in these mixed ground machines allow for ever-increasing efficiency and reduction of project risk due to unexpected conditions. We will explore the performance of recent mixed ground machines throughout the world and then look at how new improvements to mixed ground machines will enable excavation of an expanded range of ground conditions. These conditions include mixed ground with low fines, mixed face rock, and fracture/fault zones with high pressures where in the past a Slurry TBM may have been utilized.

Dec 1, 2022

By Lawrence R. Molsather

Certain hydrologic parameters are affected by development of a mine. These include the area, yield, and storage in a watershed. Alteration of these parameters results in variations in lake levels and stream flow rates and in changes in ground water elevations and gradients. These factors have become increasingly important in light of present environmental design standards and government regulations. Mitigation of adverse hydrologic impacts can be costly and can create operating constraints which complicate the mining process.

Jan 1, 1980