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By Jason Weck, Alper Turan, Ali Chehadeh

"Rapid expansion of urban areas dictates the need to expand/rehabilitate the existing buried infrastructure at the same rate. The technical challenges such as variable soil and rock profiles, high groundwater tables and limitations imposed by the built environment combined with present fiscal and schedule limitations necessitates the implementation of fast and cost effective construction methods. Since drilling procedures and equipment allow the construction of overlapped pile systems in almost all subsurface conditions, the secant pile walls have become a cost-effective shoring option for such infrastructure expansion/rehabilitation projects. The secant pile walls constructed in a circular plan layout to form a vertical shaft provide unique advantages since they act as a compression ring. Secant pile walls require stringent drilling tolerances be achieved in order to provide structural support and to work as a compression ring in addition to a groundwater cut-off wall.This paper outlines design methodology, installation procedures and verification techniques used for the secant pile compression ring for the Waterloo Landfill Pumping Station No.2. The secant pile compression ring had a 6m inner diameter with over a 20m wall depth and over 18m excavation depth. The details of subsurface conditions, analytical and numerical methods used in design are presented here. The details of the monitoring system are introduced and results of monitoring are presented and compared with analytically estimated and numerically simulated quantities. The results presented in this study are considered to be of interest to those involved in design and construction of vertical circular shafts."

Jan 1, 2014

By KNona C. Liddell

Goethite is an important naturally occurring sorbent for divalent heavy metals and has often been used as a model compound in studies of adsorption on oxide mineral surfaces. Surface complexation modeling, surface spectroscopy, and electrochemical techniques have all been applied to goethite adsorption. Modeling studies have shown that usually several different sets of fitted parameters are equally successful in representing surface charging and adsorption data. Surface spectroscopic data are proving valuable in determining the nature of the surface sites, and refined models now incorporate structural information on interatomic distances and coordination numbers. Multisite surface complexation models can give very good fits to surface charging and adsorption data, but further improvements are needed to better represent surface reactions involving exchange of protons and divalent cations. Recent experimental and modeling studies on adsorption of divalent transition metals on goethite are described and the present status of the field is assessed.

Jan 1, 1999

By Fábio Luiz dos Santos

As ligas de alumínio, em particular, apresentam certas restrições quando submetidas ao processo de união por soldagem. Isto se deve, principalmente, por apresentarem elevada condutividade térmica, elevada contração na solidificação e elevada solubilidade de hidrogênio. Levando em conta estes aspectos, o processo de soldagem FSW apresenta grande potencial para esta aplicação, visto que, é autógena, realizada sem fusão do material e sem utilização de escórias ou gases de proteção. A partir deste conceito, o objetivo do presente trabalho é avaliar a união de chapas finas de alumínio da liga 3105 H26, com espessura de 0,7mm. Para realização dos testes, foram analisados fatores como: penetração da ferramenta nas chapas processadas, ângulo de ataque, tipo de ferramenta e modo de controle de penetração (posição ou força). Os resultados indicaram que o modo de controle por força se mostrou o mais indicado para chapas finas, e que o regime transiente no início de soldagem foi a parte mais crítica para controle da qualidade da junta soldada.

Aug 16, 2017

By L. J. Health

Synthetic rock with predictable porosity and permeability has been Prepared from mixtures of sand, cement and water. Three series of mixes were investigated primarily for the relation between porosity and permeability for certain grain sizes and proportions. Synthetic rock prepared of 65 per cent large grains, 27 per cent small grains and 8 per cent Portland cement, gave measurable results ranging in porosity from 22.5 to 40 per cent and in permeability from 0.1 darcies to 6 darcies. This variation in porosity and permeability was caused by varying the amount of blending water. Drainage-cycle relative permeability characteristics of the synthetic rock were similar to those of natural reservoir rock. INTRODUCTION The fundamental behavior characteristics of fluids flowing through porous media have been described in the literature. Practical application of these flow characteristics to field conditions is too complicated except where assumptions are overly simplified. The use of dimensionally scaled models to simulate oil reservoirs has been described in the literature. 1-3 These and other papers have presented the theoretical and experimental justification for model design. Others have presented elements of model construction and their operation. In most investigations the porous media have consisted of either u ncon soli da ted sand, glass beads, broken glass or plastic-impregnated granular substances—materials in which the flow behavior is not identical to that in natural reservoir rock. The relative permeability curves for unconsoli-dated sands differ from those for consolidated sandstone. The effect of saturation history on relative permeability measurements is discussed by Geffen, et a1.4 Wyga15 has shown quite conclusively that a process of artificial cementation can be used to render un consolidated packs into synthetic sandstones having properties similar to those of natural rock. Many theoretical and experimental studies have been made in attempts to determine the structure and properties of unconsolidated sand, the most notable being by Naar and Wygal.6 Others have theorized and experimented with the fundamental characteristics of reservoir rocks. This study was conducted to determine if some general relationship could be established between the size of sand grains and the porosity and permeability in consolidated binary packs. This paper presents the results obtained by changing some of the factors which affect the porosity and permeability of synthetically prepared sandstone. In addition, drainage relative permeability curves are presented. EXPERIMENTAL PROCEDURE Mixtures of Portland cement with water and aggregate generally are designed to have certain characteristics, but essentially all are planned to be impervious to water or other liquids. Synthetic sandstone simulating oil reservoir rock, however, must be designed to have a given permeability (sometimes several darcies), a porosity which is primarily the effective porosity but quantitatively similar to natural rock, and other characteristics comparable to reservoir rock, such as wettability, pore geometry, tortuosity, etc. Unconsolidated ternary mixtures of spheres gave both a theoretically computed and an experimentally observed minimum porosity of about 25 per cent.7 By using a particle-distribution system, one-size particle packs had reproducible porosities in the reproducible range of 35 to 37 per cent.6 For model reservoir studies of the prototype system, a synthetic rock having a porosity of 25 per cent or less and a permeability of 2 darcies was required. The rock had to be uniform and competent enough to handle. Synthetic sandstone cores were prepared utilizing the technique developed by Wygal.5 Some slight variations in the procedure were incorporated. The sand was sieved through U. S. Standard sieves. A 18-20 sand denotes that the sand passed the Number

Jan 1, 1966

By R A. Lynch, D A. Malovichko

The implementation of routine real-time micro-seismic monitoring of open pit mine slopes has been discussed. Some examples of seismic arrays have been given, and a recommendation of suitable seismic sensors made. Unfortunately near-surface sensors are required for good location accuracy, and the effects of reflection, mode conversion and surface waves must be accepted and compensated for during processing of the seismograms. It makes sense that mining at the base of a slope and levels of seismic activity within the slope should be related, and this is confirmed using both 2002-2003 and 2005 seismic data recorded at Navachab mine. An example of how seismic data can be used to gain information about seismically active geological structures has been described. The removal of broken rock, and not blasting nor the breaking of supporting rock, has been found to cause slope micro-seismicity. While the standard Brune source model is suitable for some 20% of the seismic events, unreasonable results are obtained for the rest. A moment tensor inversion has been performed after S-wave splitting and surface effects have been filtered out. This approach confirms a predominantly shear mechanism for a typical high frequency source.

Jan 1, 2006

By James H. McCutchan

The small and remote mine operators must comply with the Federal Mine Safety and Health Administration regulation requiring them to train and maintain mine rescue teams. The alternative is for the operators to contract with established teams within two hours travel time of their mine. Many of these remote operations are too far away from established teams and have too few employees to make up the necessary teams. Many cannot comply with the regulation either from a manpower or economic standpoint. The Office of Arizona State Mine Inspector, under the direction of the Honorable James H. McCutchan, State Mine Inspector, entered into a contract with the Bureau of Mines to develop the concept of a volunteer mine rescue program. This program with the assistance of the mining industry and volunteer rescue organizations, has planned and instituted a statewide volunteer mine rescue organization. The trained and equipped volunteers are stationed throughout the state and can respond to a mine emergency within the time constraints.

Jan 1, 1984

The contiguous Kotre Basantpur and Pachmo (KBP) coal blocks in the Hazaribagh District of Jharkhand State in east India are being developed by Tata Steel Limited (Tata Steel) to supply coking coal to a new steel mill at Kalinganagar in Orissa.The planning challenges are many. The multiple coal seams range in thickness up to 6 m and extend to nearly 500 m depth, with dips up to 25¦ and highly variable quality. Several normal faults with throws up to 150 m intersect the deposit. There is little room for waste dumping on the lease, several large nalas (seasonal creeks) cross the blocks, and the KBP leases are not contiguous with Tata Steel's existing mining operations at West Bokaro. Geotechnical conditions, while not well defined at this stage, are largely unfavourable. There are several villages on the blocks, and extensive paddy fields. In 2009, Adelaide Mining Consultants Pty Ltd (AMC) completed a Detailed Project Report (DPR) for a production level of 8 Mt/a. A terrace mining system was proposed using 28 m3 hydraulic excavators and 185 t trucks working horizontal up-dip slices. Subsequently the viability of in-pit crushing and conveying was assessed, but the full results were not available for this paper.It is planned to extract a total of 147 Mt of raw coal at a strip ratio of 5.2 bank cubic metres per tonne (bcm/t). The planned maximum pit depth is over 300 m.The project includes a washery, a 2 + 25 MW fluidised bed power station to utilise all the coarse washery rejects, and a railway spur line to carry the washed coal to the railhead some 7 km distant.

Dec 6, 2010

According to the data provided by the most recent European Survey on Working Conditions, roughly 25 per cent of the European working population is exposed to mechanical vibrations for no less than one quarter of the work shift duration, while around ten per cent are exposed for the entire work shift. The occupational exposure to whole-body vibration (WBV), in particular, represents a major health risk in mining, quarrying and civil excavation activities. In accordance with European Directive 2002/44/EC, the latest version of the Italian law on physical risks has recently confirmed the possibility of using relevant literature data on vibration magnitude in order to evaluate personal occupational exposure (vibration database or data provided by the manufacturer). Still the alternative option, based on field measurements, represents the most appropriated method of risk assessment, as it accounts for the actual operating condition at the workplace; actual operator and vehicle under investigation and specific working cycle. The article discusses the vibration measurements taken on a number of heavy machinery (excavators, loaders, trucks, dumpers, etc) employed for talc extraction in a mine located in Sardinia and the resulting personal exposure for the drivers. The assessment was carried out in accordance with the specifications of ISO 2631-1 and EN 14253.

Dec 6, 2010

By T C. Ooi, L Lu

Owing to ongoing development of new orebodies and changes to existing mining operations, new ore types with distinct mineralogy, porosity and textures are generated as feed for iron and steelmaking. Moreover, further product differentiation occurs as fine ores are increasingly beneficiated to achieve grade. A study was necessary to characterise a suite of iron ore fines in terms of their propensity for formation of quasi-particles and green bed permeability prior to sintering. In this study, two Marra Mamba bedded iron deposit (BID) samples, one Pisolitic channel iron deposit (CID) samples, two dense hematite samples (coarse and fine grained microplaty hematite), one hematite-goethite BID samples and one hematite-goethite bedded/detrital iron deposit (BID-DID) composite sample were investigated. Both Marra Mamba fines and Pisolitic fines exhibit the highest green bed permeability followed closely by hematite-goethite fines, fine microplaty hematite fines, hematite-goethite BID-DID composite fines and coarse microplaty hematite fines at a moderate sintering bed depth of 500 mm. While porous fines generally form better quasi-particles upon granulation than dense fines, the amount of moisture addition increased due to the moisture saturation of the porous fines. As sinter strands become ever larger and deeper, it was necessary to examine the granulation performance of these ore types at a range of bed depths ranging from 300 to 900 mm. On average, the green bed permeability achieved by different ore types, decreased by approximately 7.5 - 9 Japanese Permeability Unit (JPU) as the bed height was increased from 500 mm to 900 mm. In order mitigate the effect of lower bed permeability of the deeper beds, small additions of hydrated lime were investigated as a binding agent to facilitate the formation of strong micro-pellets. With the addition of three per cent hydrated lime, equivalent to approximately 2.3 per cent burnt lime, the majority of fines achieved adequate permeability for deeper bed sintering, with the exception of coarse microplaty hematite fines. In simulated coastal steelmaking sinter blends, it was found that the overall granulation performance of the blend is contributed to by individual fines constituting the blend. Therefore fines possessing favourable granulating properties impart better granulation to the blend as a whole.CITATION:Ooi, T C and Lu, L, 2013. Effects of ore type and binder addition on the formation of quasi-particles and green bed permeability at different sintering bed depths, in Proceedings Iron Ore 2013 , pp 459-466 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By H. Cevizci

"Numerical simulation of the plaster stemming method (PSM) was performed and compared with the conventional drill cuttings stemming method (DCSM). Many earlier in situ tests have proved that PSM can use the blast energy more efficiently than DCSM. Despite PSM generating more blast vibrations, it has advantages over DCSM such as better fragmentation and lower cost per unit volume of rock blasted. In this study, numerical simulation with Autodyn software using a 2D tool was employed to prove the efficiency of plaster stemming by comparing parameters such as pressure, Y-velocity, Y-force, internal energy, acceleration-Y, and compression. For example, the maximum pressure attained at the top of explosive column was 7 395 MPa for DCSM whereas it was as high as 11 945 MPa for PSM. Most of the computed parameters were significantly higher in PSM than those obtained for DCSM. This paper is the first study elucidating the efficiency of PSM by numerical simulation. It is concluded that PSM can save substantial amounts of money and effort. IntroductionThe stemming of blast-hole collars in surface mines with an inert material redirects blasting energy to the rock more efficiently, thus the blast-induced energy is utilized more effectively in breaking rock. With proper stemming, the gases should not escape due to loose stemming material. More efficient stemming with better confinement therefore increases the blast fragmentation. In addition, the distance of scatter is increased, giving rise to a looser rock pile that can be more easily loaded and transported. In order to improve the performance of a blast, stemming is used to help maintain the gas pressure over time (Konya and Konya, 2018). Proper stemming has been shown to increase the explosive efficiency by over 41% (Snelling and Hall, 1912).The most common stemming material in open pits and quarries is drill cuttings because of their ready availability at blast sites and the drill cuttings stemming method (DCSM) is a low-cost method. However, it has a major disadvantage in that dry drill cuttings eject very easily from blast-holes during an explosion, thus a great percentage of the blast energy is wasted and lost to the atmosphere. Cevizci (2012, 2014, 2013, 2017) studied blasting parameters in open pits and obtained better results with the plaster stemming method (PSM) in many limestone, basalt, and clay quarries. Moulding plaster is preferred for stemming because of the fast hardening time of 25–30 minutes."

May 1, 2019

Study on Flotation Experiment of Complex Copper-Lead-Zinc Polymetallic Sulfide Ore in High Altitude Area and its Industrial Application

Sep 13, 2010

By J Guo, K Williams, J Y. Guo, A W. Roberts, M Jones, B Chen

Numerical simulations using the discrete element method (DEM) were carried out to investigate the flow patterns and stress field redistribution at the hopper and feeder interface. The influences of different filling heights, belt speeds and clearances between the hopper bottom and feeder surface on feeder loads were studied. Meanwhile, experiments were conducted by utilising wedged plane-flow hoppers with different configurations and horizontal feeders with various clearances. The simulation results were compared with theoretical values and experimental measurements. In terms of the cases presented in this study, simulation results reveal good agreements with experimental observations regarding the flow pattern. Being similar to the theoretical values, the simulations provide close predictions on vertical feeder loads for steady flow states, but they may show significant overestimations for initial states. Additionally, suggestions are given for relevant simulation parameters based on the comparisons shown in this investigation.CITATION:Guo, J, Roberts, A W, Williams, K, Jones, M, Chen, B and Guo, Y J, 2017. Simulation investigation of flow patterns and feeder loads at hopper/feeder interface, in Proceedings Iron Ore 2017, pp 173–182 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Ö. Erdem

The investment decision making process in the insurance and finance industries is affected by new advances such as simulation techniques. These advances have improved the discounted cash flow method (DCF). In DCF, a dynamic and flexible model construction is not possible because it does not consider uncertain conditions. Each project should be evaluated taking into account the related uncertainties because the related uncertainties determine the characterization of the project. Related uncertainties can be processed in dynamic DCF, which is applicable to both financial and non-financial industries with different kind of uncertainties, such as power generation and petroleum projects. The dynamic DCF method can estimate net present value (NPV) while managing related project uncertainties with a simulation method like Monte Carlo Simulation. The simulation method is preferred because its output is unbiased. Therefore, a more realistic financial evaluation of the project can be concluded. In spite of the improvement of dynamic DCF, this project evaluation method is not used frequently in mining industry. However, the mining industry is ideally suited to this concept because it is highly dependent on estimations such as orebody size and ore grade. During the project evaluation stage, these uncertainties can be included with the dynamic DCF method. This study aims to contribute to increasing the usage of this method in mining projects. A copper reserve in Turkey is selected as a case study to apply uncertainty assessment for the evaluation of NPV.

Jan 1, 2012

By J. Nakayama

Construction of foundation piles or diaphragm walls through rocky or boulder containing formations has been long-standing difficulty. It has been widely understood that the down-the-hole hammer is the most capable mechanical means but is restricted in drilling diameter by the unavailability of drillhead sufficiently large diameter and the difficulty of disposal of cuttings. A great number of submersible motordrills have been used for the construction of cast-in-place piles and diaphragm walls and the reverse circulation system employed has demonstrated its advantage of the prompt removal of cuttings. The development of multi-head down-the-hole hammer drill combined with reverse circulation system presents a powerful engineering choice for those "hard-to-drill" ground formations. This paper will introduce the features of the system and some actual operation results in the foundation engineering through those hard rocky ground formation in some countries.

Jan 1, 1989

By Thomas C. Shapiro

This is the final article in a three-part series on microcomputers and application software in the mineral industry. The first article covered microcomputer terms and concepts. The second discussed exploration and mining software. This article will examine plant, administrative, and geotechnical software. Every effort has been made to be current in the latest software developments. Rapid change, however, is a fact of life in the computer world and any omission is inadvertent. Introduction Geotechnical disciplines have received considerable attention in software programming. Calculations are repetitive and the formulas needed to solve them are not extremely complicated. These programs are ideally suited to the microcomputer and the microcomputer is ideally suited to the consulting geologist or engineer, due to its low cost and reliability. In fact, the advent of the Apple (a registered trademark of Apple Computer Inc.) and, more recently, the IBM personal computer has caused an explosion of inexpensive software programs available to the microcomputing public. Another area that has benefited from computerization, although not in the same way, has been mineral beneficiation. Here, process control for start-up or phase-down operations has been used in newer plants for some time. Programs to perform various calculations are becoming more common as micros increase in number. Tappi Journal has a section with solutions to handheld-calculator and microcomputer problems. Process Modeling Most process modeling is still done only on mainframes. One such program is called ASPEN PLUS (a registered trademark of Aspen Technology), and a one-week course is recommended so the user can best use the program. This program is available through timesharing from University Computing Co. Programs to find an optimal solution using Linear Programming (LP) have been around for some time. Also, plant process simulation has been possible using simulation programs. Both simulation and LP are expensive to program and run. Although there are LP programs available for some micros, the user must be fairly knowledgeable about how to set up the problem. This is because each problem must be set up as a unique program that typically requires custom programming. There are some programs that can handle blending of mine crudes and examine economic parameters over the life of the mine. Plant Applications Areas relating to mine and plant applications with programs available for micros are maintenance, production reporting, inventory, accounting, and personnel scheduling. Maintenance Maintenance typically requires that certain jobs be performed in a particular sequence and parts be ordered with enough lead time for maintenance to take place on time. There is, therefore, a critical sequence of tasks that must be performed or the scheduled maintenance will not take place. Two answers needed for maintenance project scheduling are: what is the lead time needed

Jan 4, 1984

Properties of coal which are significant in relation to preparation for carbonization and conversion are reviewed, and existing coal preparation technology which has been used for production of cleaned coal of suitable ash content and petrographic composition for carbonisation, pyrolysis, hydrogenation and similar processes is described. Possibilities for application of this technology to some Australian coal seams is examined briefly. It is concluded that further survey work is required related to the optimization of selective crushing and concentrating operations, with the aim of maximizing production of quality products for carbonisation, etc mainly from Australian seams with only moderate coking characteristics.

Jan 1, 1980

By C. M. Harrer

The location, features, quality, and extent of iron ore deposits are evaluated in this Bureau of Mines report. The results of pioneer beneficiation on Wyoming taconites and their success are discussed along with developments in the iron-ore mining industry, markets, and economics. Market potential, transportation, resource developments, taxation, cost of iron ore enterprises, and the future of Wyoming iron resources are evaluated. Although occurrences of iron ores in Wyoming were known prior to 1870, early production to 1900 was as a nonferrous metallurgical flux and as mineral pigment for paints. In 1901, the Hartville-Sunrise hematite deposits were available to the Western iron and steel industry and in 1962, the first western taconite operation was placed in production at Atlantic City, Wyo. This investigation disclosed the probability of other large iron deposits in Wyoming. Taconite in the Bradley Peak area of the Seminoe Mountains has a potentiality of 100 million tons; that in the Owl Creek Mountains may prove very large also. Pioneer beneficiation testing has been included, and results have been generally encouraging. Research continues on the large titaniferous magnetite deposits of Albany County, Wyo. At present high-density titaniferous magnetite is being mined and processed at Iron Mountain for heavy-aggregate and as a sized coating for underwater pipelines. Ample mineral raw materials needed for mining and processing Wyoming iron ores are available. Investments for iron-ore processing plants will generally be large, particularly for taconite and titaniferous magnetite.

Jan 1, 1966

By C. M. Harrer

The location, features, quality, and extent of iron ore deposits are evaluated in this Bureau of Mines report. The results of pioneer beneficiation on Wyoming taconites and their success are discussed along with developments in the iron-ore mining industry, markets, and economics. Market potential, transportation, resource developments, taxation, cost of iron ore enterprises, and the future of Wyoming iron resources are evaluated. Although occurrences of iron ores in Wyoming were known prior to 1870, early production to 1900 was as a nonferrous metallurgical flux and as mineral pigment for paints. In 1901, the Hartville-Sunrise hematite deposits were available to the Western iron and steel industry and in 1962, the first western taconite operation was placed in production at Atlantic City, Wyo. This investigation disclosed the probability of other large iron deposits in Wyoming. Taconite in the Bradley Peak area of the Seminoe Mountains has a potentiality of 100 million tons; that in the Owl Creek Mountains may prove very large also. Pioneer beneficiation testing has been included, and results have been generally encouraging. Research continues on the large titaniferous magnetite deposits of Albany County, Wyo. At present high-density titaniferous magnetite is being mined and processed at Iron Mountain for heavy-aggregate and as a sized coating for underwater pipelines. Ample mineral raw materials needed for mining and processing Wyoming iron ores are available. Investments for iron-ore processing plants will generally be large, particularly for taconite and titaniferous magnetite.

Jan 1, 1966

Water Balancing in Mineral Processing - Issues and Opportunities

Sep 13, 2010

An Ammonia Leaching-Solvent Extraction-Electrowinning-Flotation Process for Copper Oxidised Ore Treatment

Sep 13, 2010