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By David E. Albus, Ahmadreza Mortezaie, Bidjan Ghahreman

The structural evaluation of seismic performance of an existing hospital in Long Beach, California, required spring constants of foundation elements. The structure included support by deep foundation elements comprised of belled (underreamed) caissons. The available relationships in the governing building code (ASCE41-13) to compute axial stiffness is not applicable due to the belled configuration of the caissons. The large diameter of the bells required consideration of the foundation medium to the axial stiffness; a detail not clearly described in ASCE 41-13. Furthermore, prescriptive equations in ASCE 41- 13 used to estimate lateral stiffness only consider pile groups with the assumption that the only source of lateral stiffness is the axial reaction of individual piles. These assumptions were invalid for the project at hand where all caissons are configured as single foundation elements, not a pile group. In the present work, the approach taken to estimate seismic stiffness of single-belled caissons is described which accounts for the elastic behavior of the foundation medium below the bell base and lateral behavior of single-pile shafts. Results of the work provide a more satisfactory derivation of the spring constants consistent with current modeling methods. INTRODUCTION Seismic evaluation of an existing hospital in Long Beach, California, required geotechnical investigation followed by site-specific ground motion analysis. This evaluation was required by the Office of Statewide Health Planning and Development (OSHPD) in order to meet the requirements of the Structural Performance Category 4D (SPC-4D) published as a part of the 2016 California Building Code, CBC (Section 3412A). SPC-4D utilizes ASCE41-13, as modified by OSHPD, and involves two seismic performance objectives: BSE-1E (20% probability of exceedance in 50 years) and BSE-2E (5% probability of exceedance in 50 years). Spring constants and capacities of foundation elements were needed for evaluation of the structural performance of the building subjected to these two performance objectives. Our review of the as-built foundation plans indicated that both shallow footings and caissons were used for support of the structure. The plans demonstrated that all caissons are belled (under-reamed) and are individual, i.e. not part of pile groups. In this paper, the subject site condition and foundation elements are described first. This is followed by details of assessing spring constants and vertical capacities for belled caissons. The new requirements of the 2016 CBC concerning the evaluation of critical facilities will likely entail evaluation of other structures with belled caissons due to the more extensive use of these foundations in the past. This paper proposes a method to address the conditions of individual belled caissons not explicitly considered in the current code provisions.

Jan 1, 2018

By F. du Breuil

BCR National Laboratory (formerly Bituminous Coal Research, Inc.), under a USBM con­tract (originally with the Department of Energy), monitored the installation and operation of a computer-based belt-monitoring and control system at the Barnes & Tucker Coal Co. Mine No. 20, Ebensburg, PA. The system installed was the National Coal Board's Mine Operating System (MINOS) coal transport monitoring and control system. The program objec­tive was to document (1) the installation requirements for a conveyor control system, (2) the operating experience with the system, and (3) the impact of monitoring and control on mine operation. Analysis of the system operation indicates that monitoring and control did improve belt availability significantly, and reduced downtime associated with belt delays. Economic analysis showed the increased belt availability would potentially result in significant production increase, and, therefore, excellent payback on the initial investment. The system performed satisfactorily, was well accepted by the work force, and did not increase the maintenance workload.

Jan 1, 1987

By Manuel Sanchez, Marcial Medina, Matt Hurley, Hugo Granados, Pramod Kumar, Raj Rajamani, Jose A. Delgadillo

"Large-diameter ball mills have traditionally used steel liners—steel being a highly durable material that can be shaped into any desired geometry, among which the double-wave has been the preferred design. Such a design produces a purely cascading charge motion, which is ideal for the shearing action needed to produce a finer product. Today, however, rubber liners, which have been in existence for over forty years, are now preferred over traditional steel, largely because they weigh less and are easier to maintain. In this paper, we show the operating data from the Hudbay Minerals’ Constancia Mine, wherein the liners on a 26-by-40-foot mill were changed from conventional steel liners to PolyStl™ liners. It is then shown that this change reduced the amount of energy consumed whilst being able to maintain previous grind and throughput levels. The design is verified via discrete element simulations.IntroductionThe Constancia Mine (“Our Business: Peru,” 2016) is located in the southeastern Andes of Peru, at an elevation of approximately 4,200 m. It can be accessed via the CU-126 road, about 95 km from the town of Espinar in Espinar Province. The mine also contains both the Constancia and Pampacancha deposits in the Province of Chumbivilcas. Hudbay Minerals, Inc. acquired the mine in 2011, through the purchase of Norsemont Mining, Inc. and currently retains sole ownership of the property. Production of the Constancia Mine began in 2014, with commercial production levels being achieved in April 2015.The Constancia and Pampacancha deposits primarily include hypogene, supergene, and skarn ores. The Mine’s main products, however, are copper concentrate, with silver contents, and molybdenum concentrate. These mineral reserves are expected to last approximately 22 years. Constancia’s open-pit mine supplies a processing plant that is designed for 81,900 metric tons per day of throughput. Average annual copper production is estimated to be 82,000 mT (contained metal in concentrate). Actual plant production can be found in Table 1."

Jan 1, 2017

The Tasman Orogenic Zone is regarded as a single metallogenic province (the Tasman Province) with four SUb-provinces corresponding with its major tectonic components: the Lachlan, New England, Hodgkinson.and North Queensland orogenic provinces. Within the Tasman Province there are four main ore-rock associations.These are1. manganese and iron with sedimentary and basic volcanic rocks,2. zinc-lead-copper and copper with intermediate-acid volcanic sequences,3. minor chromium, platinum, and osmiridium with ultramafic complexes, and4. tin, wolfram, gold, and copper with syn- and posttectonic granitic intrusions.Whereas the ores of ultramafic and volcanic associations form geographically-restricted metallogenic districts, the ubiquitous granitic ores may be subdivided into twenty-one districts that cover almost the entireOrogenic Zone. The Tasman Province is notably lacking in uranium ores and Mississippi Valley-type deposits.There is a distinct tendency for ores of each association to be progressively younger to the east and north, thus paralleling the progressive growth and stabilization of the Zone. Similar ore-rock associations are present in repeated phases of mineralization from the Cambrian to the Permian-Triassic, reflecting the essential homogeneity of the Tasman Province, and the similarity of the successive tectonic cycles.

Jan 1, 1972

By Benoit Virollet

Over the last 10 years the diameter of unbraced, unlined and unanchored circular shafts has grown dramatically in many parts of the world. This progress has taken place through improvements in: construction methods; concrete rheology; and design capabilities. Excavation equipment has become more precise in terms of operator control and ability to correct alignment of digging elements leading to better alignment tolerances. Also contributing to the increases in shaft diameters is the evolution of design models. A better understanding of soil structure interaction is being incorporated into the analyses in terms of radial soil stresses and imposed loads on the shaft. This paper provides an overview of the recent progress made in circular shaft construction, the primary design considerations, and some innovative uses of efficient arc elements to develop unsupported structures of other shapes. In addition, a summary of recent circular shafts constructed worldwide is provided.

Jan 1, 2006

By Walker G. S

A study of the crystalline materials on or near the surface of freshly made or "green" superphosphate granules and mature, "set" superphosphate granules was undertaken using X-ray diffraction, X-ray mapping, scanning electron microscopy and electron probe micro analysis techniques. Calcium sulphate (CaSO4), calcium sulphate hemihydrate (CaSO4 1/2H20), and mono calcium phosphate monohydrate (Ca(H2PO4)2H2O), were the only crystalline species present in the "green" superphosphate.In the set superphosphate however, additional compounds were present, namely complex iron and aluminium phosphates Ca(Fe,AI) H(HPO4hF2)2H2O, (Fe)3(H3O)H8 (PO4)6H2O and calcium sulphate dihydrate (CaSO4.2H2O).The complex phosphates tied up the major part of the Fe and Al in the system and were concentrated on or near the surface of the granule. An intimate mixture of CaSO4.2H2O, and CaSO4, along with the above mentioned complex Fe-AI compounds, crystallize close to the surface of the granule and cause the setting of superphosphate that takes place during storage.

Jan 1, 1980

By S Chew, A Bennett, N Di Giorgio, B Osborne

After relining one of two blast furnaces and enlarging its sinter plant in 2009, BlueScope radically restructured its Port Kembla steelworks operation in 2011, shutting a blast furnace and halving its total production. This drastic move in response to unprecedented raw material prices relative to achievable steel prices was like that of many integrated steelmakers worldwide facing similar challenges. The 2011 restructure also saw major changes in the amount and type of iron ores and ferrous burdens purchased, and a fundamental reappraising of ‘value’ in iron ores. This paper outlines the changes to raw materials purchases from 2011 to 2017, how BlueScope has responded to the changes in pricing and raw materials quality, the effect on the sintering and blast furnace processes at Port Kembla resulting from higher gangue content, some of the broad technical and economic challenges faced by steelmakers confronted with lower quality iron ores and how BlueScope is meeting those challenges.CITATION:Di Giorgio, N, Bennett, A, Osborne, B and Chew, S, 2017. Recent Port Kembla experience with iron ore use – sintering and blast furnace, in Proceedings Iron Ore 2017, pp 25–30 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Zajber A, Kulchen R, Letzel D, Weyer A, Schwellenbach J

The search for modem casting plant concepts today focuses more and more on the harmonisation and optimisation of overall concept lines to obtain a continuous quality control and reduce the cost of production (Figure 1). Fin I As far as continuous casting plant concepts are concerned, this specifically requires an optimal adaptation and flexible operation when converting liquid steel into a directly processable product without any in-between treatment. Continuous casters need to fully satisfy the requirements of both the upstream steelmaking facilities as well as the downstream rolling facilities.

Jan 1, 1999

The commercial application of electrolysis to zinc sulphate solutions for the production of metallic zinc is a development ·of the past twenty years. Earlier attempts failed to give satisfactory results, chiefly because certain harmful elements were either not recognised as being present in the solution, or, if recognised, suitable methods of removal had not been developed. The electrodeposition of zinc from zinc sulphate solution is extremely sensitive to the influence of a great many factors, all of which appear to be closely inter-related.Some of these factors tend to minimise the necessity for a high degree of purity of the solution, while other factors aggravate the harmful nature of certain impurities.The relationship existing betweBn the various factors in zinc electrolysis makes a general discussion of the injurious effect of impurities very difficult since, under one set of conditions a given concentration of an impurity may be of minor: importance, where its under another set of conditions the same concentration of that impurity may prove dangerous to successful electrolysis.

Jan 1, 1934

By H Zhou, T Honeyands, M Zhou

In iron ore sintering, packing the granules onto the sintering strand to form a porous bed with optimum permeability is a complex dynamic process. The packed bed voidage is the key factor determining the flame front speed and the final sinter productivity and quality. Previous studies have found that granules are soft quasi-particles with a typical structure of nuclei with an adhering fines layer. The deformation of the adhering layer greatly affects the bed voidage during packing, which is related to the strength of the adhering layer and the force exerted on the granules. In this study, tablets simulating the particle size distribution in the adhering layer of granules were made for four single ore blends. Both the tensile strength and shear strength properties of these tablets were investigated as a function of water content by the uniaxial compression test and direct shear test respectively. The results of compression tests show that the adhering layer becomes weaker and more compliant with the increase of moisture. The most porous ore has a more rigid adhering layer than the other three tested iron ores at any given moisture content. In direct shear tests, the internal friction angle of the adhering layer ranged from 31° to 37° and varied little with the moisture content or ore type. The cohesion constant is around 1 kPa and is quite small compared to the stress applied to the granules during packing. Combined with the results of granulation and packing experiments, the influence of the adhering fines layer deformation on the degree of voidage loss is specifically discussed.CITATION:Zhou, M, Zhou, H and Honeyands, T, 2017. Tensile strength and shear strength properties of the adhering layer of granules in iron ore sintering, in Proceedings Iron Ore 2017, pp 117–112 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Mike Neill, O&apos

? Bypass soft soils near the surface ? Resist uplift loads ? Resist lateral loads ? Bypass scourable soils ? Bypass liquefyable soils ? Mitigate movement of expansive or frozen soils ? "Tune" foundations for vibrating machinery

Jan 1, 1998

By J. -F. Lessard

Most underground mines rely on ore pass systems to ensure the transport of ore and waste. The design and operation of ore pass systems often rely on past experience, which is often anecdotal and at times contradictory in nature. This paper summarizes the current practice in Quebec underground metaliferous mines. The information was collected during a series of site visits in ten underground mines. The database includes information on ore pass configuration, support, materials transited, and overall ore pass performance.

Jan 1, 2006

By Adam Moore, Peter Radziszewski, Matt Gallimore

"Stirred mill technology dates back to 1928 where the idea to use “an agitator and spherical grinding media” was presented. In the context of the mining industry, interest in stirred milling technologies has grown over the last 20 years where the typical observation reported inDespite these developments, the tumbling mills are continuing to be used in fine and ultrafine grinding applications. The main reason for this, as communicated at the Canadian Mineral Processors roundtable discussion in 2013, is that the comfort level in understanding stirred milling technologies is not at the level of that of tumbling mills.At CMP 2014, one contribution was made to explore how mill design affects power and energy in a stirred mill. While the 2015 CMP paper explored the application of one scale-up methodology to the Gibraltar case. For the CMP 2016, the aim of this paper is to contribute to increasing the general comfort level with stirred milling technologies by developing a better understanding of the different scale-up methodologies used. This will be accomplished by first completing an overview of the scale-up models found in the literature followed by a review of the different testing and scale-up procedures. This review will be supported by a number of case studies found in the literature. The paper will close with a discussion on some of the challenges that these models and methodologies have and how future research might contribute to overcoming them.IntroductionStirred mill technology dates back to 1928 where the idea to use “an agitator and spherical grinding media” was presented (Stehr, 1988). The year 1948 saw the successful application of Du Pont’s “sand mill” for pigment grinding. Subsequent years have led to the development of different types of stirred mills spanning a number of industries that require fine and ultrafine grinding."

Jan 1, 2016

By James V. Errico

On October 1, 1993 the regulations for assessing and cleaning up contaminated soil and groundwater in the Commonwealth of Massachusetts were revised. These new regulations, known as the Massachusetts Contingency Plan (MCP) 310 CMR 40.0000, were developed to keep routine releases out of the regulatory system and rely on private parties to handle most releases without Department of Environmental Protection (DEP) oversight. An integral part of the new MCP is the Licensed Site Professional (LSP). An LSP is required to handle activities and render opinions once a site enters the MCP. These regulations must be adhered to where ever a release has occurred, including construction sites. A brief overview of the new MCP is given below; see attached MCP Flowchart for graphical summary. Entering the MCP Process A release of oil or hazardous material (OHM) to the soil or groundwater above applicable reportable quantities (RQ's) or reportable concentrations (RC's) will require notification to the DEP and compliance with applicable provisions of the MCP. RQ's and RC's are listed in the MCP (310 CMR 40.1600) for most compounds that are typically encountered. For each compound there are two RC's for soil (S-1 and S-2) and two for groundwater (GW-1 and GW-2). The S-1 and GW-1 RC's apply to sites that are environmentally more sensitive, as a result they are lower than the S-2 and GW-2 RC's.

Jan 1, 1994

By E. Harris

Frithia humilis is an endangered succulent plant species. Its distribution range overlaps with the coal fields of Mpumalanga and it is therefore threatened by opencast mining activities in particular. One of the 11 known populations of F. humilis was translocated from a licensed coal mining site to three suitable receptor sites within the species? distribution range. A longterm monitoring programme was initiated to track the progress of the newly established populations. Temporal trends in population demography, size classes, and fecundity were recorded. Population numbers of size classes fluctuated annually. However, flower frequency increased over time and seedling recruitment contributed significantly to population growth. Receptor sites with similar geological conditions to the donor site had more persistent cohorts, which suggest that such sites should receive priority during the translocation of endangered edaphic specialists. This study not only confirms that a Frithia humilis population can successfully establish after a translocation, but also serves as an important baseline for future comparative purposes to gauge the long-term success of the translocation effort.

Jan 1, 2014

By C. Edwards

ABSTRACT The versatility and specificity of rare earth elements (REEs) have led to their use in an everincreasing variety of applications in new technologies; consequently, demand for REEs has increased significantly. However, separating REEs safely and effectively is a complex and expensive process. This paper presents a review of REE mineral processing technologies, providing an update on current capabilities in REE mineral processing and REE extraction from the major commercially valuable REEbearing minerals such as bastnaesite, monazite, and xenotime, as well as the ion-absorption type of REE deposits.

Jan 1, 2013

By Circadian Technologies

Alertness levels naturally fluctuate during the day and night Basic functions ??digestion, body temperature ? follow predictable 24-hour patterns Adjustment to night work creates health challenges for shiftworkers Performance decreases during overnight and post-lunch dip hours Fatigue supercedes training & experience Fatigue is a major cause of human error

Jan 1, 2010

By Mukhopadhaya K. K, Cory A. H

The concept of using travelling magnetic fields created by linear motors was stimulated by Laithwaite who advanced ideas on motors with shaded poles (Laithwaite, 1968), rack and pinion motors (Laithwaite, 1970) as well as low speed, brushless motors and three dimensional motors (Laithwaite, 1973a and 1973b).Sudan (1963) and Sundberg (1969) had applied the concept to metallurgical processes. However, the use of travelling magnetic fields has not been used widely to produce conditions for the separation of magnetic from non-magnetic minera1s or even magnetic materials from non-magnetic materials, although some attempts were made by McCarthy (1922), Davis (1934), Dean, Gottschalk and Davis (1934) and Gottschalk (1934).Laithwaite (1973, a) while working with linear motors made suggestions for designing separators and in the work described here, the observations of Laithwaite and others are extended to determine the characteristics of the motor with a view to using it as a magnetic separator.

Jan 1, 1980

By Joseph N. Bakambu

It is currently recognized by mining society that autonomously guided underground mining vehicles may greatly increase the efficiency of mining production and improve human safety. Recent results in mobile robotics, data fusion and sensor development provide a solid basis for solving the problems related to autonomous underground navigation. Recently developed commercial systems mostly rely on the infrastructure that is expensive and difficult to maintain. Guideless navigation in unstructured and harsh environment of underground mines is still a challenging task. In this paper, we describe an autonomous navigation system for an underground mining vehicle equipped with on-board dead reckoning, inertial and optical sensors. This system does not require any artificial infrastructure and is capable to guide the vehicle along the complex environment of interconnected underground drifts; it also ensures the detection of obstacles on the vehicle path. The user interface for monitoring and control is described and the results of laboratory tests and on-site experiments are presented. Work in progress addresses the system integration for real equipment, and the system upgrade, adding map-building and selflocalization capabilities .

May 1, 2002

By Dennis W. Boehm

The building boom of the late 1970's and early 1980's has all but used up most of the better sites across the more populated metropolitan areas of the United States. This means that current buildings and other types of structures are being founded on more marginal sites. The use of marginal sites has placed ever-increasing quality control on the installation of the deep foundation systems utilized for these sites. Several remedial techniques are available for the repair of the deep foundation systems. These include minipiles, compaction grouting and jet grouting. Eight case histories are cited where these methods have been utilized to repair deep foundations.

Jan 1, 1999