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By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

A sociotechnical system (STS) creates a framework that allows an examination of how social and technical factors affect organizational outcomes within a specific environmental context. STS has been rigorously studied with a primary research focus addressing worker-technology interactions. Although these interactions are important, the social processes and interactions that occur whenever any technical or environmental change is introduced into the system have been undervalued. If social processes are better understood, mining organizations could efficiently prepare and stabilize for such changes. With this goal in mind, we sought to extend STS theory through applying principles of meta-design to analyze the results of two case study interventions. Specifically, we studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the Continuous Personal Dust Monitor) on factors within an STS including employees’ knowledge of, communication about, and use of technology to mitigate respirable dust sources. The results are presented in a way that first, addresses the overarching principles of meta-design STS including organizational participation, flexibility, and communication and second, examines how technology implementation processes differ when the organization is complying with a formal, higher-level requirement. Results show that a prominent focus on the social factors within an STS framework could help reduce unpredictability on the technical side and may improve communication within the system to help reduce adoption time, especially if and when accompanying a new, formal work process.

By Andrew B. Cecala, Emily J. Haas, Jay F. Colinet

A sociotechnical system (STS) creates a framework that allows an examination of how social and technical factors affect organizational outcomes within a specific environmental context. STS has been rigorously studied with a primary research focus addressing worker-technology interactions. Although these interactions are important, the social processes and interactions that occur whenever any technical or environmental change is introduced into the system have been undervalued. If social processes are better understood, mining organizations could efficiently prepare and stabilize for such changes. With this goal in mind, we sought to extend STS theory through applying principles of meta-design to analyze the results of two case study interventions. Specifically, we studied the impact of an unregulated dust control technology (the Helmet-CAM) and a regulated dust control technology (the Continuous Personal Dust Monitor) on factors within an STS including employees’ knowledge of, communication about, and use of technology to mitigate respirable dust sources. The results are presented in a way that first, addresses the overarching principles of meta-design STS including organizational participation, flexibility, and communication and second, examines how technology implementation processes differ when the organization is complying with a formal, higher-level requirement. Results show that a prominent focus on the social factors within an STS framework could help reduce unpredictability on the technical side and may improve communication within the system to help reduce adoption time, especially if and when accompanying a new, formal work process.

By Hamid Mahmoudabadi

In the present paper, the performance of four approaches based on neural networks and geostatistical method for grade estimation are compared and analyzed their performance to find a proper method. Four methods, Multi Layer Perceptron neural network (MLP), Radial Basis Function (RBF), General Regression Neural Network (GRNN) and Ordinary Kriging (OK) are selected for ore grade estimation of variable Fe in an iron deposit located in Iran. For each method, two diagnostic statistics are calculated: Mean square error (MSE) and correlation coefficient. The results show the superiority of the General Regression Neural Network.

Oct 1, 2009

By Alicia Esther Ares

The family of Zn-Al (ZA), Zn-Ag and Zn-Al-Ag (ZINAG) alloys offers high mechanical properties, ease of finishing, the advantage of low energy and pollution-free melting. Also, present alternatives to the well developed alloy systems, such as brasses, bronzes, cast irons and aluminum alloys. The main objective of this paper is to measure thermal parameters in ZA, Zn-Ag and ZINAG hypoeutectic and hypereutectic alloys directionally solidified which present columnar, equiaxed and columnar to equiaxed transition structures (CET). Also, estimate the mechanical properties, such as microhardness and tensile parameters and correlate these with the thermal (cooling rate) and structural parameters (grain size and dendritic spacing). The different types of structures were analyzed with optical and scanning electron microscopy. The results showed the influence of concentration, microstructural arrangement and thermal conditions during solidification on the mechanical properties. The results of the present investigation are compared with previous experiments.

Jan 1, 2010

Caving of the second lift of the E26 orebody at Northparkes Mines was monitored with a comprehensive package of instrumentation, including an ISS seismic monitoring system. Seismicity was collected by an array of 19 triaxial accelerometers and 9 uniaxial geophones, giving a high quality seismic data set. The seismic response to block caving at Northparkes has been divided into two papers. The first paper focuses on the seismicity during undercutting. The second paper deals primarily with the seismicity during cave propagation during initial cave production. In this paper, traditional seismic monitoring concepts are applied to seismicity during cave mining. More than 40 000 seismic events were recorded during cave undercutting between February and January 2004. Events up to local magnitude +1.3 were recorded near the mine during undercutting, with event rates of up to 500 per day. Analysis of frequency-magnitude distributions, S-wave to P-wave energy, and temporal variations in event magnitude all gave insight into the seismicity recorded. In addition, a new technique, called apparent stress time history, was shown to be sensitive to stress change from undercut blasting, and useful to identify significant periods during cave development. A significant difference was identified between the cave back location and the halo of seismic events above the cave. Throughout the undercutting, the a seismic zone of loosening was typically 50 to 70 metres in vertical thickness. Based on the seismicity, a stress driven rock mass failure model is proposed. Early in the undercutting, seismicity and movements in the seismogenic zone were directly triggered by stress change from undercutting. Towards the end of undercutting, seismicity was virtually uncorrelated with undercut blasting, and likely due to the onset of cave initiation.

Jan 1, 2008

By Alex Del Castillo

The mineral processing industry has followed the development of database control systems, and various systems have been installed in existing and new plants. The goal is to improve product quality, raise productivity and lower production costs. Improvements in different units for mineral .processing .have been applied. This has led to increasing information for the operators. To support the operators and for an easy overview of the process, a complete concept for an integrated process-control system is required. This paper describes the plant-wide [process control system for the Collahuasi copper project located in northern Chile. The total investment for the project was $1,700,000,000 and included a port area and two copper processing plants, an oxide plant with a cathode production of 50 tons per year and a sulfide plant with a concentrate production of 330 kilotons per year. The main characteristics of the plant-wide process control system include a 200- kilometer long redundant control network and a 24-kilometer long redundant serial network providing coverage for the entire plant. The plants are located around 4,700 meters above sea level, serial communication lids allow the integration of over 2,700 SCADA data units, and the system handles over 7,500 physical signals plus the SCADA data integration. The main equipment consists of 39 different sized controllers, 16 operator stations, 5 engineering stations, 2 information management systems and 4 X- terminals. The project management, control configuration, factory acceptance test, system integration test, training, commissioning and start-up were carried out in close cooperation with the customer. The result was completely satisfactory for the customer.

Jan 1, 1999

By H. R. Butler, J. F. Church, A. T. MacGibbon

Introduction Inco is the major North American nickel producer. Initially based in Sudbury, Ontario, its past exploration activity was directed toward finding new nickel deposits. New nickel sulfide discoveries outside Sudbury have included Thompson, Manitoba; Shebandowan, Ontario; and Widgiemooltha in Western Australia as well as a host of nickel laterite deposits. The company is currently diversifying into other commodities, including gold. Inco's exploration department participated in uranium discoveries in Saskatchewan and chromite discoveries at Tiebaghi in New Caledonia. In addition, it found new gold deposits at Lupin, Northwest Territories; Crixas, Brazil; Hoyle Township, Ontario; and Casa Berardi in Quebec. Crixas and Casa Berardi are currently being evaluated by underground exploration. Figure 1 shows some Canadian Shield gold locations where Inco is or was an active participant. Base metal developments Base metal exploration in shield areas has been greatly eased by applying scientific studies. Archean nickel sulfide deposits have been found using komatiitic-flow models (Fardon, 1971). Volcanogenic massive sulfide model has been applied to copper-zinc deposits (Sangster and Scott, 1976). Such deposits were subsequently seen developing on the sea floor through black smokers (Spiess, MacDonald, and Atwater, 1980). Sedimentary processes were recognized early as important in ore formation, particularly in the southern hemisphere (King, 1976). And many ore deposits are now regarded as a simple part of the geological column (Stanton, 1960 and 1972). Petrographic work on alteration patterns in and around ore bodies was used to develop standard porphyry copper models (Lowell and Guilbert, 1970). Epithermal models for precious metals followed. Stratigraphic zonation patterns have been formulated for base metal deposits, including keel facies, ore facies, and cap or distal facies. Gold developments The work on base metal deposits naturally spilled over into precious metal exploration when the gold price was allowed to float on world money markets. Early work on elements associated with gold deposits, especially arsenic, tellurium, selenium, and mercury, pioneered more detailed geochemical work (Bagby and Berger, 1985; and Groves, Ho, and Houstoun, 1984). Geochemical patterns have been recognized around microfine gold deposits. And the study of gold precipitation patterns in modern geothermal systems has helped understand gold deposition. In the late 1960s and early 1970s, it was noticed that numerous Archean banded iron formations contained anomalous gold values. From this and other observations, the syngenetic exhalite gold model has developed. Gold deposits also occur along shears in some plutons such as the Belmoral mine in Quebec. This indicates the importance of epigenetic processes in ore formation. Shield ore settings Initial studies recognized that the major gold camps in the Canadian Shield were mostly in greenstone belts and found along "breaks," especially zones of faulting and sedimentation. Gill (1948) wrote, "Only recently, as a result of detailed mapping, has the importance of major schist zones such as the Larder Lake, Cadillac, Porcupine Creek, and Destor Breaks been recognized. These zones of persistent adjustment mark broad belts favorable for ore occurrence." The importance of shearing in ore location and regional greenstone stratigraphic position close to late sedimentary packages was clearly understood. And structural models have been further developed for some Canadian ore deposits (Hubert, Trudel, and Gelinas, 1984). In the Beardmore-Geraldton camp of northwest Ontario, the importance was soon recognized of fold noses in banded iron formation, as localizers for gold ore. This importance had also been recognized in Western Australia,

Jan 2, 1987

By Bethany Witter, Dyno Nobel

In the past decades, a technological explosion has caused generational shifts. First, millennials experienced a technological shift to computers and cellphones. Next, Generation Z experienced a shift to smart phones and social media. These two generations are immersed in technology and are accustomed to constant connectivity. How do the extractive and construction industries gain the interest of younger generations and integrate them into the industry?

Feb 1, 2020

By Dan A. Brown

The following paper was written by Dr. Dan A. Brown, P.E. Brown is an Associate Professor at Auburn University's Department of Civil Engineering. The paper was originally presented at a FHWA's Transportation Research Board meeting and is presented here with the author's consent. Construction and design of drilled shaft foundations in hard pinnacle limestone requires flexibility from all parties involved due to the variability of the subsurface conditions. This article describes some strategies which have been found useful in the Birmingham, Alabama area. The importance of well trained and experienced field personnel in these conditions is noted. It is also vital that engineers understand the construction challenges so as to provide both quality assurance and cost effectiveness in design and in the specifications.

Jan 1, 1991

By David Caiden, Geoffrey Fosbrook, Jaidev Sankar, Donald Phillips, Jon Hurt, Anil Parikh

This paper will cover the progress being made on Phase 1 of New York’s Second Avenue Subway line. It will include a description of construction progress on the first contract to be let, which consists of a 248 m (815 ft) long launch box, 3.9 km(2.4 miles) of TBM tunnels and a tunnel sump; the packaging strategy for the remaining work; and the progress through Final Design of the remaining packages, including the two large span rock cavern stations.

Jan 1, 2007

For small particles of niekel flotation eoncentrate (av. size 50 pm) the predominant heat transfer mechanism under suspension smelting conditions, prior to ignition, is conduction from the gas and not radiation from nearby hot bodies. Results of laboratory tests using gas temperatures 380-700°C and furnace wall temperatures 380-1100°C were in accord with heat transfer theory. In practieal flash smelters earlier ignition, and hence better utilization of the space in the shaft, would result from introduetion at the top of the shaft of gases hotter than the ignition temperature of 500-600°C.

Jan 1, 1979

By A. N. Holden, W. E. Seymour

DURING the last several years, the U-Zr system has been studied at many laboratories as one of the research programs sponsored by the Atomic Energy Commission. The equilibria in part of this system have been difficult to determine, although the phase diagram from 0 to 60 atomic pct Zr has been established with reasonable certainty. Existing diagrams of the system vary appreciably beyond 60 atomic pct Zr, particularly with regard to the existence of an intermediate phase. Most existing diagrams show a transformation or reaction horizontal near 600°C. In 1955, a collection of uranium phase diagrams' was prepared at the Battelle Memorial Institute and the U-Zr diagram in that collection contained a questionable region in the vicinity of 60 to 80 atomic pct Zr. Summer-Smith" has published a phase diagram of the system that shows no intermediate phase. Summer-Smith did his work with powders and found only the uranium and zirconium eutectoid mixture from X-ray patterns of material annealed below 600°C. Mueller3 at Argonne National Laboratory did similar work with filings, and he found that initially there was a pattern of an intermediate phase, but on long-time annealing

Jan 1, 1957

By Chikaosa Tanimoto

INTRODUCTION Bratislava is located at the intersection of important traffic routes, including motor-ways, roads, railways, air traffic, trading, and inland waterway with an important harbour. The construction of the D2 Motorway Bratislava, Lamacska cesta Stare grunty was the last missing section of D2 Motorway and its completion linked the Czech Republic through Bratislava to the Hungarian Republic. Traffic was obliged until its completion to use the Lamacska Road and Mlynska Dolina, which were the most heavily trafficked roads in the city. The section of D2 Motorway to be completed in 2006 was 3,300m in length, of which the SITINA Tunnel was approximately half the length. After putting into operation the transit traffic(motorway) and urban traffic was separated. Transit traffic by passing the town was eased. The junctions D2 with Lamacska Road (Harmincova) and Mlynska Dolina also allowed better use of the motorway for the urban traffic The tunnel construction was specified by the features with the highly weathered and thermally altered granitic rock formation with the overburden of Quaternary sediment of 2?4 m thick, very thin overburden, severely controlled deformation limit and environmental protection. The tunnel had to be excavated beneath and nearby the academic complex area and the zoo, where sensitive facilities exist and animals live in. The tunnel consisted of two tunnels (Tunnel A and B) with the length of 1,415 and 1,440 m, respectively. The overburden thickness was in the range from 10?30 m. The standard cross-section and the one with invert arch were 79.5?81.5 m2 and 92.1?93.3 m2. The excavation took 21 months from September 2003 to May 2005. The construction was based on the concept of NATM. The SITINA Tunnel was the third application of NATM in Slovakia, following the BRANKISKO Tunnel (commenced in July 2003) as the first and the HORELICA Tunnel (in October 2004) as the second NATM practice. To protect the surrounding structures and citizens from tunneling operations, seismic monitoring was performed in association with blasting. The allowable limit of blasting vibration was fixed to be under the particle velocity of 15 mm/sec. The tunnel excavation cleared this limit as expected before construction. In driving through the difficult geological situation the excavation work hit 49 faults, and some of them occasionally caused serious face instability. In principle, the rock formation has been affected by the high hydrothermal effect and the resultant clay filing along faults and joints. The auxiliary reinforcement with the 4?8 m long pipe roofing was needed to protect the vicinity of mining face area. This operation extraordinarily required additional works and time which had not been expected before construction.

By G. Abramov

The 20th Century saw the modern mining industry enriched by one outstanding method of extracting of mineral resources called Borehole Mining (BHM). Mean while, despite its successful track record in wide ranging locales, few specialists are yet aware of this technology. The intent of this article is to introduce borehole mining to a wider spectrum of drilling and mining professionals. The BHM method is based on in-situ water jet cutting of rock mass. On Fig. 1 the schematic of the method is presented. The borehole mining tool 1 is lowered into the borehole 2 and high pressure water 3 is pumped down. At the bottom part of the tool, one portion of that water comes out through the hydromonitor nozzle 4 in a shape of water jet 5 and cuts the material 6 creating slurry 7. The other portion of high pressure water then comes to the hydroelevator 8 (jet pump, eductor) which produces a vacuum. When the slurry reaches this vacuum zone, the eductor sucks the slurry and pumps it up to the surface, where rock parts are separated from water in a tank 9 or a pond and clarified water is pumped down again closing the re-circulating BHM water supply system. The borehole mining tool is suspended on a drill rig tower 10 which allows the tool to rotate and move vertically along the borehole axis. While extracting rock mass, underground caverns (stopes) 11 are created. If necessary, compressed air 12 can be injected to the raising slurry flow to create an airlift effect. Also, a secondary agent 13 (such as oil, foam, etc.) can be added to the stope through the gap between the tool and the casing. As seen from the illustration, BHM is the remote mining method of extracting of mineral resources through boreholes by high pressure water jets.

Jan 1, 2001

By A. Noble, R. Q. Honaker, J. Werner

Recovery of rare earth elements (REE) from coal-related resources has recently received significant interest due to supply concerns and their key roles in critical industries and defense-related technologies. An integrated flowsheet consisting of sorting, crushing/grinding, physical separation, acid leaching, solvent extraction, and selective precipitation was designed to achieve continuous production of rare earth products from various coal-related resources such as coarse refuse and acid mine drainage. A pilot plant was constructed that enabled continuous testing of the circuitry on a range of different coal-based feedstocks. Despite achieving significant success in producing high-grade rare earth oxide products, low REE recovery values and high operational costs necessitated a re-evaluation of the process flowsheet. This article describes the circuitry improvements that were based on both laboratory and pilot plant test results. Roasting as a pre-leach treatment was found to significantly improve the leaching rate and overall REE recovery values. After roasting West Kentucky No. 13 and Fire Clay coal refuse materials at 600 °C, REE recovery increased by 60 and 40 absolute percentage points, respectively. Rare earth concentration in the pregnant leachate solution (PLS) was increased to around 700 ppm prior to solvent extraction using a staged precipitation method. REEs in the precipitate were re-dissolved, purified, and extracted from the PLS using solvent extraction and selective precipitation to values of around 80%. As a result of the improvements, chemical consumption in the acid leaching and solvent extraction processes was significantly reduced. A techno-economical assessment of the improved flowsheet indicated significant commercialization potential.

Used in conjunction with geology and geophysics, geochemistry provides powerful exploration tools of special relevance to Australian environments. New methods are needed that will confront the forthcoming emphasis on locating concealed orebodies. Deep weathering is conducive to techniques using groundwaters or gaseous emanations as sample media. Increasing use is anticipated for isotope measurements and for recognition of country rock characteristics that denote proximity to mineralization. Improvements in the sensitivity, reliability and portability of analytical instruments will underpin the contributions of geochemical methods to future mineral exploration.

Jan 1, 1982

By A. Noble, R. Q. Honaker, J. Werner

Recovery of rare earth elements (REE) from coal-related resources has recently received significant interest due to supply concerns and their key roles in critical industries and defense-related technologies. An integrated flowsheet consisting of sorting, crushing/grinding, physical separation, acid leaching, solvent extraction, and selective precipitation was designed to achieve continuous production of rare earth products from various coal-related resources such as coarse refuse and acid mine drainage. A pilot plant was constructed that enabled continuous testing of the circuitry on a range of different coal-based feedstocks. Despite achieving significant success in producing high-grade rare earth oxide products, low REE recovery values and high operational costs necessitated a re-evaluation of the process flowsheet. This article describes the circuitry improvements that were based on both laboratory and pilot plant test results. Roasting as a pre-leach treatment was found to significantly improve the leaching rate and overall REE recovery values. After roasting West Kentucky No. 13 and Fire Clay coal refuse materials at 600 °C, REE recovery increased by 60 and 40 absolute percentage points, respectively. Rare earth concentration in the pregnant leachate solution (PLS) was increased to around 700 ppm prior to solvent extraction using a staged precipitation method. REEs in the precipitate were re-dissolved, purified, and extracted from the PLS using solvent extraction and selective precipitation to values of around 80%. As a result of the improvements, chemical consumption in the acid leaching and solvent extraction processes was significantly reduced. A techno-economical assessment of the improved flowsheet indicated significant commercialization potential.

By Richard Kastner, Emilie Vanoudheusden, Fabrice Emeriault, Jacques Robert

INTRODUCTION The subway line B of Toulouse (France) has been realized with three different tunnel boring machines (TBM) techniques: Contracts 2 and 5 are excavated with earth-pressure balanced TBM, Contract 4 with a slurry shield TBM, and Contract 3 with a compressed-air TBM. The first three machines are around 7.7 m in diameter, while the last one is 5.3 m. Moreover, a small part of the line (50 m) has been excavated by a conventional method. The tunnels run through the Toulouse molasses, composed of hard sandy clay with pockets and lenses of dense sand. Geotechnical investigations have shown that in these formations, K0 is greater than 1, around 1.8 at a depth of 25 m (Serratrice,2005) and that geotechnical characteristics are homogenous on the whole layout (? =22 kN/m3, Su = 300 kPa, c' = 30 kPa, F' = 32°). The water table is found between 2 and4 m below ground level. As geology, stratigraphy and tunnel cover (between 10 and 20 m) are almost identical, a comparison of movements induced by the excavation by each of the four excavation techniques is possible. This paper presents the soil mass movement measures in the case of the conventional excavation method and in the case of TBM sections. It shows how tunneling parameters may explain the different surface movements observed during excavation. For the sake of simplicity, only the results of Contract 2 (earth pressure balanced TBM)will be presented. MONITORING Monitoring for the Conventional Method Section For the conventional method section (Vanoudheusden et al. 2005) the mass soil movements are measured with two inclinometers and one multi-point extensometer borehole with automatic data acquisition (Figure 1). The monitoring devices include

Jan 1, 2007

By Stephen C. Tadolini, Peter (Yunqing) Zhang

A unique circumstance created by monitoring a pre-driven longwall recovery room permitted measuring the stresses of a coal pillar throughout its entire life cycle in less than a week. A fender pillar, created in approximately the middle of a longwall panel at a depth of 650 ft, transformed from a solid barrier pillar - to a yielding pillar - to a residual pillar as 3 ft slices were methodically removed with the longwall shearer. The complete transformation, or life cycle, took place in less than 12 hours. The stresses were quickly transferred from the pillar onto the standing pumpable concrete supports and into the outby pillars. Roof to floor closure measurements, combined with the timing of the pillar behavior, provides a detailed look at the uncontrollable convergence of underground mine openings. Pillars remain the most important form of “primary support” and understanding these life cycles is vital for safe and efficient mine design, in both room and pillar and longwall panel extractions.

By Hamed Mirzadeh

The hot working behavior of 17-4 PH stainless steel was studied using the hot compression test at temperatures of 950-1150 °C with strain rates of 0.001-10 s-1. A step by step procedure for data analysis in hot compression test was given. The work hardening rate versus stress curves were used to reveal whether or not dynamic recrystallization (DRX) occurred. At low Zener- Hollomon (Z) parameter, this material showed a new DRX flow behavior, which was called Multiple Transient Steady State (MTSS). At high Z, as a result of adiabatic deformation heating, a drop in flow stress was observed. The general constitutive equations were used to determine the hot working constants of this material. Moreover, after a critical discussion, the deformation activation energy of 17-4 PH stainless steel was determined as 337 kJ/mol.

Jan 1, 2010