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By Rodrigo Fina Ferreira, Jacek Kolacz, Luciana Gois, Neymayer Pereira Lima

The recent developments on the sensor detectors together with the higher capacity of the machines, due the high-speed computing recent advances, have made possible extending the application in the mining industry. The use of x-ray fluorescence, x-ray transmission and radiometric sensor based sorting can selectively remove gangue minerals in different size fractions for different minerals. This paper summarizes the potential application of SBS for an iron ore in three size fractions aiming to increase the %Fe after the removal of particles with main gangue minerals associated. Pilot plant tests were carried out with samples of iron ore in different size fractions and different content of hematite and gangues. The use of x-ray transmission sensor showed the possibility to increase the %Fe from about 63% to above 68% for particles below 80mm and 45mm, after the removal of low density particles. The presence of fines on the feed affected the performance of the SBS X-rays transmission machine, especially for the fine fraction feed. The mineralogical determination, carried out to know the association between hematite and gangue minerals, and the density of the particles on the feed, can be used to preview the quality of products of the x-transmission sorting process.

Oct 3, 2019

By A. E. Koski

This paper will review recent developments in the area of mine planning at the Empire Mine. It illustrates how one of the largest iron mines in North America has adapted computerized mine planning to meet the unique requirements of their mining operation.

Jan 1, 1994

By S. J. Jung

In recent years, the use of shotcrete, a practice familiar to the mining industry, has been on the increase. This research has come about because of the recognized need for a safe, easy way to line small diameter bored raises (less then 150cm). Up until now, an operator has gone down the raise and applied the concrete lining manually, using the shotcrete method of application. With an automated system, there would be no man positioned in the bore itself. All control functions could be commanded from a central location. Shotcreting in the confined space of a small diameter bored raise presents problems that can be overcome by the application of shotcrete using a remote system.

Jan 1, 1994

By R Blin, R Walde, R Belli, D Inaudi

A fiber optic distributed sensing system allows the monitoring of parameters useful to determine the short- and long-term behaviour of the structure in response to the external actions, including, eg seismic activities as well as long-term phenomena such as seepage, tunneling, sinkholes, and other geo-structural movements. Monitoring of large retaining structures with such a system provides direct strain/deformation and temperature measurements on the broad interior area with an arrangement of several sensing cable lines, enabling early detection, localisation and sizing of subsurface damages. Measurements are provided every meter along the entire sensing cable, this is particularly important in such cases where the location of defects and damages cannot be predicted. Fiber optic distributed sensing cables are generally available for retrofit installation inside the dam structure using trenches on the downstream face or laid during construction below the geomembrane liner within the bedding sand layer. Mapping the cable route enables exact correlation between a linear coordinate on the cable length and a position in the dam. Cable installation is envisaged to be carried out during further raising of the embankment; additional cable sections are plugged to the previously installed cables and measured with the existing measurement system, requiring only an update of the mapping. The measurement system is placed remotely from the sensing area since a section of sensing cable can be used to link to the sensing area at the storage facility several kilometers away. The system is available for on-line, 24/7 real-time operational data management. Such fiber optic distributed sensing systems allow storage facilities to be monitored with long, accurate, continuous and precise data for geotechnical diagnostic purposes. This contribution will introduce the principles, benefits, and limitations of this technology.

Jul 1, 2021

By F C. D Michelin

As mines get deeper, the critical underground temperature limits will be exceeded, and an increasing number of mines will need to implement, expand or modify cooling systems. Surface cooling plants have many advantages over underground cooling such as efficient heat rejection, and lower relative capital cost; however the delivery of cooling through long underground distances can result in lost refrigeration capacity before the chilled air reaches the areas it is needed most. Refrigeration plants are therefore often overdesigned in size and capacity to compensate for underground losses.More mines are now utilising real-time monitoring and automated control of ventilation airflow and fan systems to ensure the conditions underground are safe and productive, and power consumption is efficiently managed. There may be significant opportunities to extend ventilation monitoring and control into the refrigeration delivery and control system.Energy reduction is an effective way to reduce costs and CO2 emissions, which is an increasingly important part of corporate governance. More efficient refrigeration control is a further step toward reducing energy consumption. This paper looks at an added step in how real-time monitoring can assist in controlling the output and chilled air delivery of a cooling plant. The requirements, implementation, benefits and challenges will be discussed.

Oct 12, 2022

By A Mooney, G Balog, P Burns, R Brooks

This paper outlines the rationale for the location of the crusher, geotechnical analysis and basis of ground support design, design and scheduling of the chamber and supporting excavations as well as the operational outcomes and lessons learned. Contributions from mining operations, planning, geotechnical and infrastructure teams enabled the Crusher Station One excavation to be completed on schedule, with opportunities taken for underground mining and infrastructure to work safely in parallel to deliver crusher station infrastructure on schedule. Installation of crusher infrastructure was ongoing at the time of writing.

Mar 15, 2021

By Dan A. Brown

The foundations at the Huey P. Long Bridge in New Orleans presented special challenges for construction due to the requirements for very deep drilled shafts in the Mississippi River beneath the existing bridge structure. Drilled shafts were constructed to depths of approximately 200ft in alluvial soils using a rotator system with full-length segmental casing, and base grouted to improve axial resistance. This paper describes the design and construction of the work platform to provide access to the restricted-access site beneath the existing bridge, the approach used to construct the drilled shafts, and the results of a load test program to verify the axial resistance.

Jan 1, 2010

By Alessandro Bertero, Stefano Valagussa, Filippo Maria, Wesley Schmutzler, Leoni

"Abstract The Deep Mixing Method (DMM) represents a viable solution to improve the adverse geotechnical properties of foundation soils. Differences and the importance of performing pre-construction laboratory and field tests will be highlighted. Comparative analyses and interpretations between the various lab and field stages, along with accumulated information about soil properties and QC results, allowed fine-tuning of the production parameters throughout almost the entire project.Two projects where the US Army Corps of Engineers selected the Deep Mixing Method (DMM) for the required stabilizations, and a third project completed in Italy, will be illustrated:•,?the LPV 111 Project (New Orleans - LA – USA); DMM was used for groundimprovement/foundation strengthening and consequently stabilize and support the burden of the new levee.•,the Rio Puerto Nuevo Project (San Juan - PR - USA); DMM was applied to improve the soils adjacent to a 90” forced sewer main relocation and to improve the soils for the base of a new drainage channel•,the new Italian high speed railway project (Florence Italy); DMM technology was applied to realize a a TBM break in/break out, foreseen originally by jet-grouting.IntroductionThe Deep Mixing Method (DMM) represents a viable solution to improve the adverse geotechnical properties of foundation soils. The effectiveness of working parameters depends largely on the physical and mechanical properties of the soil to be treated. Therefore, well designed laboratory and field test programs, aimed to disclose the interaction between the site-specific soils and the mixing parameters, are essential to achieve the desired end product."

Jan 1, 2014

By Chunli Wei, Mark Jen, Xiaojun Wang

"After more than 85 years of service, a critical link between New York and New Jersey, the Goethals Bridge over the Arthur Kill waterway, is being replaced with two new parallel bridges. Each bridge includes 1,650 feet long signature steel composite cable-stayed bridge, a 2,789 feet long New York approach and a 1,889 feet long New Jersey approach. The superstructure of each approach is supported on a series of two-column concrete piers and each column is supported on a single large diameter drilled shaft varying from 4.5 to 9 feet in diameter and anchored 45 feet below ground into the underlying rock.A performance-based methodology was followed for the strength and extreme event limit states design of the drilled shaft foundations. The design for seismic loads has been performed using the AASHTO Guide Specifications for LRFD Seismic Bridge Design. For all strength and service loads, the AASHTO LRFD Bridge Design Specifications were used. Since the longitudinal and confinement requirements in the two specifications vary, the minimum longitudinal reinforcement was based on the more stringent requirements of the two codes. A design example is presented to illustrate the methodology in bridge deep foundation design using nonlinear time-history global analysis results with soil-pile interaction represented by sets of horizontal and vertical nonlinear soil springs along the drilled shaft, based on the soil and rock properties from the boreholes test results. In this paper the design methodology implements strain limits related to earthquake intensities and damage levels to calculate the capacity using XTRACT analysis, which aids designers to adopt applicable provisions that meet specific design requirements.INTRODUCTIONAfter more than 85 years of service, a critical link between New York and New Jersey, the Goethals Bridge over the Arthur Kill waterway, is being replaced with two new parallel bridges designed to carry vehicular traffic and a future mass transit corridor. They include two 1,650 feet long signature steel composite cablestayed bridges with 260 feet tall V-shaped concrete gateway towers (Figure 1). The approaches consist of continuous pre-stressed concrete girders. The New York approach is a single structure consisting of 18 continuous spans, sloping at 4% for a total length of 2,789 feet without expansion joints. Similarly, the longest continuous portion on the New Jersey approach, with a similar slope, consists of 11 spans for a total length of 1,889 feet without expansion joints. The superstructure of each approach is supported on a series of two-column concrete piers that vary in height from 121.3 feet near the cable-stayed bridges to 11.8 feet near the abutments. Each column is supported on a single large diameter drilled shaft varying from 4.5 to 9 feet in diameter and anchored 45 feet below ground into the underlying rock."

Jan 1, 2016

By G. Akdogan, C. Bergmann, C. J. Coetzee, Q. G. Reynolds, S. J. Baumgartner

Submerged arc furnaces (SAF) are used extensively in the production of ferrochrome, where charge material – consisting of mixtures of carbonaceous reductants, fluxes such as silica, and ore in the form of pellets – is fed through chutes into the vessel. The feed typically forms a thick bed or ‘burden’ of solid particulates above a bath of molten material below. This burden layer surrounds three electrodes, which are typically arranged in a triangular configuration in circular SAFs. A major challenge in the industry is the availability of sought-after reductants, volatile market conditions, and increasing electricity tariffs in South Africa. A good understanding of the physical properties of the raw materials in the charge is therefore of great value in order to best deal with the reductants available at any given time, and thereby maximising furnace throughput. This paper presents a study of the effects of different particle properties on particle flow behaviour relevant to SAF operations. Discrete element model (DEM) simulations were used to estimate the sensitivity of the particulate flow of beds of charge material to properties such as the coefficients of friction, particle shape and size, and others. The present study lays the groundwork for the development of full DEM models of the SAF that will greatly improve understanding of the flow of complex mixtures of solid particles in the submerged arc furnace, and how the relative physical properties of each component in the charge can influence electrical behaviour of the burden.

Sep 1, 2021

By Stephen M. Voynick

Two hours driving time west of Denver, CO and 21 km (13 miles) north of Leadville, Bartlett Mountain rises 4,065 m (13,337 ft) high in central Colorado's Tenmile Range. Bartlett Mountain is one of Colorado's most recognizable peaks, especially when the late afternoon sun casts a surreal, reddish light across its most prominent feature - the Glory Hole. This is a gaping, half-mile-wide, 245-m- (800-ft-) deep crater. Created by subsidence from 60 years of massive underground mining, the Glory Hole is a monument to the Climax Mine, one of the great achievements in American mining and metallurgy. For most of this century, the name Climax has been synonymous with brilliant mining engineering, innovative metallurgical research and entrepreneurial promotion of a once-obscure metal - molybdenum. Climax overcame an array of economic, technological and social problems to become a model for underground development of massive deposits of low-grade ores. It is one of the few mines in the world where cumulative production is measured in the billions of dollars. The Climax mineralization was emplaced 30 million years ago. Magmatic intrusions formed a large, mineralized stockwork within the granite country rock of Bartlett Mountain. Associated hydrothermal events forced superheated metal- and quartz-rich solutions through fracture zones, silicifying the country rock and depositing huge amounts of molybdenite, or molybdenum disulfide. The mineralized rock, a light gray, finely crystalline, silicified granite, is laced throughout with blue-gray quartz veinlets containing molybdenite. Although the richest ores graded only about 1% molybdenite, the Bartlett Mountain deposit contained more than 2.7 Mt (3 million st) of elemental mo- lybdenum.

Jan 1, 1997

By Tapio Ahokainen, Asmo Vartiainen

"Outotec's portfolio contains a wide variety of smelting solutions for non-ferrous metals. Some of these include flash smelting for primary copper and nickel, flash converting for copper, Ausmelt technology for primary and secondary copper, nickel, tin, lead, and zinc residues and waste, Kaldo technology for secondary copper, lead, and precious metals recovery. Outotec also offers slag cleaning technologies and much more.Company provides complete process solutions tailored to each customer's individual needs. Decades of experience have resulted in extensive metallurgical know-how that ensures the most profitable process choice and optimal performance. Outotec's life cycle technology partnership with their customers spans from the early stages of process solution design through the supply and commissioning of the entire process chain. They include integrated process control and holistic service and support concepts. Continuous research and development ensures that the customer is provided with the latest advancements in process and equipment solutions.IntroductionOutotec develops and provides technology solutions for the sustainable use of the Earth's natural resources. Solutions are ranging from various processes and special equipment needed for metallurgical extraction and mineral processing of ores to the production of refined metals and minerals. The processes include not only the grinding and physical separation of ores but also the smelting and leaching of base metals and precious metals. The company provides engineering services for whole projects as well as life cycle services on the equipment and products that they supply."

Jan 1, 2012

By Wang Xianzheng

For a long period of time, the Chinese Government has been attaching great importance to and supporting the rapid development of the coal industry. Particularly since more than 30 years ago, when China introduced the Reform and Opening-up policy, the reform and development of the Chinese coal industry has witnessed world-recognized achievements. National coal production increased from 618 million tonnes in 1978 to 3.52 billion tonnes in 2011. While China?s coal production accounts for 49.5% of the world?s total, its annual production growth contributes to over 80% of global production growth. China is a country utilizing coal as its main source of energy. As the Chinese Government gives support to the rapid development of new and renewable energy sources, as well as to increased coal utilization efficiency, the ratio of coal in the primary energy consumption mix will gradually decline. However, for a long period of time to come, the total volume of coal demand will keep rising modestly. The Chinese Government has been highly committed to and actively promoting the overall, coordinated and sustainable development model, which puts people first. It has put forward a strategic task to build an ecological civilization, and highlighted its resolve to uphold the basic national policy of resource conservation and environmental protection, with a view to the pursuit of sustainable development. China will incorporate its response to climate change into the national economic and social development program, and take effective measures to lower CO2 emissions 40?45% per unit of GDP in 2020 compared to 2005. At the same time, China will increase the ratio of non-fossil fuels to 15% in the primary energy consumption mix. All of the above factors have raised requirements for the Chinese coal industry, with implications for clear directions, plans and goals for the development of the coal industry.

Aug 1, 2013

By Robert C. Maxton

The foundry industry is a basic source of structural component for all industry. Millions of tons of castings are produced annually in both ferrous and nonferrous alloys. These castings are subjected to a wide variety of heat treatments, finishing techniques, mechanical tests and machining operations. Through all of these steps the quality of the casting is of paramount importance to the end use of the product. The Quality Assurance Program at Minneapolis Electric Steel Castings Company is designed and established to provide a superior product for both original equipment manufacturers and the mining industry.

Jan 1, 1982

By Matthew T. Mowry

As the mining industry continues to hire young professionals to supplant the growing number of retirees, a well-developed engineering curriculum, coupled with practical, real-world training, can prepare mining engineering graduates to make meaningful contributions in the industry. Successful companies can be measured not only by their reserve base and annual production but also by their retention of mining engineering graduates with zero to five years of operational experience. My personal experience in the industry during the last five years has been varied and rewarding. The knowledge and experience I have gained have taught me valuable lessons that prepared me for my current role.

Nov 1, 2013

By Xinyang Wang

It is believed that sulfur and volatile matter con-tents in coals are the main intrinsic properties to cause the self-heating of coal. Their oxidation at lower temperatures than that of fixed carbon to initiate coal's self-heating should be quantified. This study is aimed to improve the previous mathematical model developed by the authors for studying the coal's propensity for spontaneous combustion. It enhances the model's ability to consider the effects of sulfur, volatile matter and moisture contents in the coal three important factors affecting the coal's self-heating process. Sulfur exists in coal primarily in the form of pyrite which will be oxidized rapidly under suitable conditions. Volatile matters, higher in low rank coals, are more easily to be oxidized. Heat of water condensation provides initial energy for low temperature oxidation. Heat release rates for pyrite oxidation and moisture condensation are built in the model. Finally, the simulation results in terms of time versus temperature on pyrite oxidation and moisture condensation are validated with the adiabatic testing data respectively.

Jan 1, 2013

By Colin Connors

Cemented rockfill is a key component in the success of underground mining at the Jerritt Canyon Joint Venture. The Murray and SSX mines are characterized by relatively poor rock mass quality, and the goal of complete mining recovery makes maintaining a high quality backfill product vital to the safety and efficiency of the mining operations. A large portion of the ore production from the Murray mine originates from drifting under backfill. Modelling studies performed to investigate induced loading of the backfill were used to develop engineering specifications for the backfill material. Operations history has shown an almost 100 percent stability of the backfill when mining is carried out beneath it. The volume of backfill required each year (approximately 300,000 tons) and the required cement content have a significant impact on the total mining costs. The potential for cost savings associated with higher replacement of cement with Type "C" fly ash and the implementation of a backfill strength management strategy were therefore evaluated.

Jan 1, 2001

By David M. Cregger

The performance of the nation's first geologic repository for Commercial High Level Waste will be evaluated in a variety of ways which will involve the use of the state-of-the-art thermomechanical computer codes. Elastic properties of the host rock and the materials surrounding the repository are required for this numerical modeling effort to assess both near- and far-field effects. Only limited laboratory testing is possible, however, making it extremely beneficial to expand the data base by calculating dynamic elastic properties from available geophysical well logs. Elastic theory dictates that for an isotropic solid there are only two independent variables in addition to mass density, namely the compressional velocity, the shear velocity, and Poisson's Ratio. Compressional velocity and density are readily measured by geophysical well logs or in the lab; the crux of the solution requires measuring or determining either the shear velocity or Poisson's Ratio. Examination of acoustic propagated shear waves measured during confined compression testing demonstrates that Poisson's Ratio is a fundamental lithology-dependent parameter. Once a rock mass is appropriately classified, application of the laboratory derived dynamic Poisson's Ratio will yield a continuous and reasonable in situ modulus from acoustic and density logs. For preliminary characterization and assessment of the mechanical properties of rocks within the subsurface, and for studies of rock quality, this method is sufficiently accurate. The general availability of acoustic and density logs from wells logged for other purposes has made the application of this method desirable.

Jan 1, 1984

H. Van F. Furman, Denver, Colo. (communication to the Secretary): There are some statements in Dr. Carpenter's interesting paper which appear to require explanation, if not modification.

Jan 1, 1901

By Patrick B. Kenny

Generally speaking, it is safe to address this conference as a conclave of Engineers, Owners' Agents, Governmental Representatives, and Contractors. As a group, we have assembled here to learn of our compatriots engaged in similiar underground operations throughout the United States and the World. We are here to learn of improved methods, higher technology, and better management. Through the acquisition of this knowledge, we each hope we can improve our own particular services, products and projects. This session is dedicated to a discussion of "Costs". The most apparent reason for a discussion of costs at this level is to expose subjects affecting costs and propose methods to reduce them. From that premise a contractor can identify three areas of discussion: design considerations, contract considerations, and governmental considerations. A fourth area of consideration is an introspective view of the contractor's role in the design construct process. Unnecessary costs and risks attributable to these areas are contributing excessively to ever increasing project and system costs. DESIGN CONSIDERATIONS On April 20, 1977 the Metropolitan Sanitary District of Greater Chicago accepted proposals for the Tunnel and Reservoir Plan on Contract A and Contract B. This letting called for construction of over 33 km (21 miles) of the Mainstream Tunnel bored at 9.75 m (32 ft) to 10.67 m (35 ft.) in diameter. Also included were all the appurtenant collecting and regulating structures. The proposal allowed the

Jan 1, 1979