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By Christian Hoyme, Jochen Maurer

Most of the current foundation projects are suffering from disconnected information silos. In the first silo there is the planning of the project with corresponding data, presented by paper or digital drawings. Here will Building Information Modeling (BIM) be one of the trends for the future. We will see more and more projects leaving the “old way” of 2D drawings and moving into 3D planning including metadata of the foundations. But even with a perfect BIM model of a jobsite, we are not at final end of digitalization. While execution of the project at the jobsite, a second data silo is evolving. Data collected directly from construction equipment and manual measurements is currently undervalued in most projects. Paper is passed to the equipment operator and major data from measurements on site are noted on paper and digitized afterwards. Automatically collected data is not be used to create site progress reports or similar report. So, the real “data” just flows around without connection to any other data already existing in projects. And then the third silo arises: The documentation of the project. Data collected on paper es reentered to create some basic documentation of the work handed over to the client. Spreadsheet software is still the “tool-to-be-used” to create at least some documentation. Finally, the documentation is not connected to the data created while planning and not connected to the automatically collected data from the jobsite. A connected jobsite in the foundation industry must link these information silos and have to create a full data-workflow from the design through the execution to the as-built documentation. INTRODUCTION Building information modelling (BIM) is currently the most popular term of construction business in Germany and probably all over the world. But as often there are many different definitions out there and everyone has his own definition or at least understanding what BIM is about. But for sure it is the most relevant for the construction industry in the near future. Most popular is the digital twin for the upper structure of a building. In most cases the BIM models just shows the building itself, but there is more to be implemented. For example: projects where a special foundation is needed, BIM should include also the foundation elements with meta data. There are several advantages. Not only the clash detection of anchors, but also the possibilities to check the interaction with neighbor constructions, power lines and so on are a use case. For sure most of the special foundation elements are not relevant for the whole lifecycle of a building. But during construction and later the demolition the information about the hidden elements is important and gives a benefit to all stakeholders. In the future there will be not the question: “What is already in the ground?”. The risk for following construction projects on the same ground will be minimized.

Jan 1, 2019

By Thomas J. Peters

The Lime Creek study area lies 100 air km east of Boise, and 70 air km northeast of Mountain Home, Idaho. The eastern boundary of the 28,000-hectare, east-west-elongate study area lies 0.2 km west of the 3,077-m-high Smoky Dome. The area is mainly underlain by Cretaceous granitoid rocks of the Idaho batholith. No mineral resources were identified, but two mines and one prospect were found in the study area. At the President and the Last Chance mines, in the southwest corner of the study area, gold mineralization occurs along steeply dipping east-northeast-trending faults and associated quartz veins, and within adjacent Cretaceous granitic rock. The mineralized material is not rich enough to mine underground, and near surface, open-pit-mineable deposit areas could not be identified. The third prospect, the Ventura, is within altered pink granite of probable Tertiary age, but metal concentrations are very low. Geothermal activity was not observed within the study area, but hot springs do occur in the Vicinity. Bedrock observed is only suitable for the most basic high bulk and low end value applications, such as crushed aggregate. Numerous sources for crushed stone occur closer to markets. Alluvial concentrate (placer) samples did not contain free gold, and no substantial alluvial bars were seen; deposits were too small to contain resources.

Jan 1, 1993

By Ruilin Yang

Kinematic approach of blast modeling refers to using the velocity, strain, or displacement as controlling parameters to model blasting, rather than the stress and the material constitutive relations. The rock stiffness or constitutive relations is very hard or impossible to obtain due to the complexity of the rock mass property.

Feb 1, 2020

By A. M. Clegg

In general, overall experience has shown that the approach to the appointment of a project manager is given much attention, but little specific attention is given first to the risk associated with the project conceptual design and its overall executability within either the new legislative framework or the sustainability of the outcome. The risk in project executability and sustainability within the ?new age? legislative framework of the Mining Charter, etc, is itself however, of far greater importance. The degree of importance being defined by the intended projects impact on the business going forward. This is particularly the case where the intention of the implementation is effectively to turn around or even enhance a loss-making strategic investment like a mine or process plant operation in an ?old-order rights? or Brownfield?s operation. This paper attempts to highlight the importance of a ?pre-project project? (PPP) to mitigate the risk in the ?new age?, with specific reference to operational due diligence (ODD) and project conceptual design.

Jan 1, 2005

By D. J. Burger

This paper will highlight the system components of a successful underground mining automation project recently launched at DeBeers Finsch Mine. It will also show that integration of short-term mine planning with other upstream and downstream mining processes in the extraction of kimberlite ore from a block cave is not just critical to the future sustainability of this underground mining operation but also for profitability and cost-effectiveness. This paper will discuss the information data flow required from the mine-planning process through to production for underground block cave mining. The benefits associated with this type of integrated mine planning and automation system will be highlighted.

Jan 1, 2006

By G Pizarro, O Miranda, D Rosales

In panel/block caving mines, large amounts of information are collected at the operations. This information includes grades and extracted tonnage, fragmentation, lithology, design of stopes and main infrastructure, geotechnical information, overbreak progress, seismicity, numerical modelling and many other mine variables. To improve the reliability of the production plan it is required to integrate the mine data into one platform. In this paper, the logic of a new technological platform is presented for analysis, modelling and design in panel/block caving mines. The platform includes an acquisition system for mine data and geotechnical information, a back-analysis module for calibrating statistical models and a module of visualisation of the results. The application and benefits of the platform is illustrated for mining induced seismic risk for panel/block caving mining operation. The platform can be used in the mine design and planning processes and is useful for reducing uncertainty in the mining business of panel/block caving operations.CITATION:Miranda, O, Rosales, D, Pizarro, G and Vallejos, J, 2016. Development of an integrated platform for the analysis, modelling and design in panel caving mines, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 237–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By James J. Dowd

The investigation to evaluate the reserves of coking coal in the United States suitable for the manufacture of metallurgical coke is being made by the Bureau of Mines in three parts: (1) To estimate known (measured plus indicated) recoverable reserves of all coking coal; (2) to study the carbonizing properties of coals and coal blends not now widely used for metallurgical coke making; and (3) to upgrade marginal coals through effective preparation. This is the second7j of a series of reports giving the results of studies by counties under part (1) of the investigation. This report covers Indiana County, Pa., which comprises parts of the Smicksburg, Punxsutawney, Elders Ridge, Indiana, Barnesboro, Latrobe, New Florence, and Johnstown Quadrangles. (See fig. 1.) A base map for each bed in each Quadrangle was made to the scale 1 inch equals 1,200 feet. Maps of mines, locations of drill holes, bed and total coal thicknesses, and the outcrop of the bed were plotted on the maps. With all available data plotted, isopach lines were drawn to limit areas of known unmined reserves in beds 0 to 14 inches thick, 14 to 28 inches thick, 28 to 42 inches thick, and over 42 inches thick. These areas of coal reserves also were divided into "measured" and "indicated" categories. All areas in each thickness range and in each category, mined-out areas, areas excluded from the estimate, and areas outside of the outcrop were measured by planimeter on the base maps. Estimates of total reserves 14 inches and more thick and maps for individual beds were prepared from these data.

Jan 1, 1950

By R. Grimard, M. Gamache, L. -P. Bigras, P. Cohen

This paper describes a real-time fleet management system for an undergroun mine. Dispatching, routing and scheduling are handled simultaneously, taking into account the mine status, operational constraints and vehicle location information. Each assignment decision takes into account the traffic on the road segments of the mine network, whether road segments are bi-directional or uni-directional, and ensures that each LHD (load-haul-dump) vehicle arrives at loading and dumping points with the correct orientation. Such a system can be used either as a simulation tool for strategic planning or as a real-time managing and optimizing system for operations. In the simulation mode, the system can accurately estimate the impact on productivity of decisions such as the development of waiting areas (bays, sidings), or the addition (elimination) of vehicles to the fleet in operation. When used for real-time dispatching, routing and scheduling of vehicles, the system can optimize production with respect to various assignment criteria such as cycle-time minimization or deviation from a target production plan.

Jan 1, 2004

By H. M. Thorne

The oil-shale deposits of the Puertollano basin in the Spanish province of Ciudad Real appear to have been give little consideration in discussions of oil-shale resources throughout the world. A small, integrated oil-shale operation has been conducted at Puertollano since about 1922 by a French company, Sociedad Mimora y Metalurgica de Penarroya, hereinafter referred to as "Penarroya", but only within recent years have the potentialities of the Spanish oil-shale deposits been recognized. Empresa Nacional "Calvo Sotelo" do Combustibles y Lubricantes, hereinafter designated as "Calvo Sotelo," which was created in 1942 by the National Industrial Institute of Spain to produce liquid fuels from oil shales, has made marked progress in the design and construction of a complete oil-shale plant at Puertollano. Penarroya is mainly a coal-mining company, and the oil-shale operations were on a small scale of approximately 220 tons a day in October 1947. It is an integrated operation comprising oil-shale mining and retorting and shale-oil refining. Motor gasoline, Diesel fuel oil, light burner fuel oil, lubricants, paraffin wax, cresols, and ammonium sulfate are manufactured.

Jan 1, 1950

By J. R. Goode

"The Las Cristinas deposit in Venezuela contains reserves of 12.8 million ounces of gold at a grade of 1.20 g/t (Crystallex, 2004). The deposit comprises fully oxidized saprolite (SAPO) overlying a layer of sulphide-enriched saprolite (SAPS) which lies above carbonateleached bedrock (CLB) and carbonate stable or un-leached bedrock (CSB). Gold occurs at about the same concentration in all lithological groups. The bedrock units contain minor amounts of copper (about 0.1%) as chalcopyrite, while SAPO contains virtually no copper which has been leached and deposited in the SAPS zone.A previous owner began investigation of the Las Cristinas deposit in 1991. Over the next seven years, the company drilled 1,174 holes with a total length of 159 km, conducted extensive metallurgical testwork, including pilot plant operations, and completed feasibility studies. Construction was started in 1997 and again in 1999, however, on each occasion was suspended.Crystallex has been producing gold inVenezuela since the early 1990s. In 1997, Crystallex acquired Inversora Mael which had held two of the claims to the Las Cristinas concessions since 1986. In September 2002, Crystallex entered into a definitive agreement with the Corporación Venezolana de Guayana (CVG) to develop the Las Cristinas deposit.An extensive program of studies and testwork was started in late 2002 to determine an optimum development plan for Las Cristinas. Mine Development Associates, SNC–Lavalin Engineers and Constructors, SGS Lakefield Research Limited, J.R. Goode and Associates, and A. Laplante at McGill University acted as the main contractors.Because of the potential value of by-product copper, earlier flowsheets used carbon-inleach for SAPO, but processed all other ore types by flotation to produce a gold-copper concentrate with cyanide leaching of cleaner tailings to maximize gold recovery. Cyanide recovery was necessitated by the high copper content of the leach feed. Initial studies of available data by Crystallex revealed that direct leaching of all ore types would provide about 11% more gold recovery than the previously selected flotation route with reduced capital and operating costs.Bench and pilot-scale studies have confirmed that a SAG-ball mill-gravity-CIL route is very effective for all ore types and will give about 89% gold recovery. This paper describes the testwork conducted in 2003, discusses a 20,000 t/d plant design, and presents economic data."

Jan 1, 2005

By O. W. Owings

"The handling and transportation of explosives and explosives supplies are inherently hazardous owing to their sensitiveness to impact and flame or electric arcs and sparks. Many accidents have occurred in the past during transportation of explosives, especially when they were carried by individual miners on man-trips. When electric haulage became the usual mode of transportation and shots were fired electrically, the hazards of carrying explosives and supplies on man-trips were fully realized, and in some mines all explosives were placed in one car, usually at the rear of the trip. Far-sighted managers saw the danger of this practice and provided separate trips for delivering explosives. This step was a definite advance in safety, but the latest achievement is the construction of special, rugged, nonconducting cars.Many coal-mining men have shown considerable interest in the construction of safe cars for explosives during recent months. Undoubtedly many others are interested in this phase of safety, therefore this circular is issued to give information on cars of this type now in use.Car A (fig. 1) is essentially a closed inner box separated from an outer box by an insulating lining of rubber. The double box is attached to a standard steel chassis that has spring journals and electric welding instead of certain rivets. The chassis is equipped with roller bearings. The over-all length from pin to pin is 11 feet, 9 inches; the wheel base is 54 inches, the track gage 42 inches, and the capacity eighteen 50-pound cases of permissible explosives. The box is 10 feet long, 6 feet wide, 3 feet high at the top of the arched roof, and 2 feet 9 inches at the edges. The top of the car is 46 inches above the top of the rail.The inner box is insulated from the outer box by two pieces of 1/4-inch switchboard.-insulating matting cemented together. To cover the top, two ends, two sides, and the bottom of the box requires 320 square feet of the l/4- inch matting.The walls are well-seasoned tongue-and-groove oak, 1 1/4 inches thick and 2 3/4 inches wide. A 1 1/4-inch air space is maintained by oak strips between the outer wall and the two thicknesses of 1/4-inch rubber matting. The inner box is made of 7/8-inch, well-seasoned, tongue-and groove oak fitted closely against the insulating matting. No nail, rivet, or bolt extends through the rubber insulation.The floor of the outer box is secured to the chassis by two sets of bolts through an intermediate piece of well-seasoned oak. One set of bolts is countersunk from the top of the intermediate piece of oak, and the other set is countersunk from the bottom. The countersunk portions are filled with ""insulate,"" an insulating compound. Adjacent bolts are at least 6 inches apart.The bed of the inner box is divided into six compartments by transverse strips of wood at the bottom and partitions near the roof. Each compartment accommodates three 50-pound cases of explosives. This arrangement prevents cases in adjacent compartments from touching, so that there is no possibility of end thrust of the entire load of explosives. Each inner compartment is 21 inches high, 5g inches long, and 16 1/4 inches wide. Separating strips at the floor are 3 inches wide and 1 1/4 inches thick. The outside dimensions of the 50-pound cases of explosives used are 17 1/2 inches long, 13 1/2 inches wide, and 12 1/2 inches high."

May 1, 1940

The formation and distribution of gold placers in active collisional mountain belts are directly related to the tectonic, topographic, climatic and erosional constraints prevailing on either side of the orogen at the time of placer formation. In the absence of pre-existing placer deposits, these factors combine to concentrate placer development on the side of the orogen facing the prevailing winds, where most of the erosion and uplift occurs. Drainage network changes and glaciation can significantly alter placer distribution with respect to source areas within the orogen. After collision stops, placer formation will proceed on both sides of the orogen as exhumation of the mountain belt ensues. Incorporation of pre-existing placers formed on ancient mountain belts into younger placers in subsequent orogens, may be recognised by anomalous placer distribution compared to the above model. Most of the relatively young giant placers such as those inNew Zealand, Chile, Bolivia and Columbia, exhibit these general patterns. Their character and mode of formation have important implications for the formation and distribution of much older placers, such as those in South Africa's Witwatersrand Basin.

Jan 1, 1996

Role of Bubbles in the Action of Flotation Agents

Sep 13, 2010

By Takefumi Takuma, Ali Fayad, Shigeru Kambe

"This paper discusses the unique design and construction circumstances of the cantilevered dual sheet pile walls and the Accordion Sheet Pile Wall for the repair and upgrade of the East Garden Grove-Wintersburg Channel in Huntington Beach, California that was concluded in 2014. It also describes the 2008 Emergency Sheet Pile Project for the same channel. Both projects utilized the Press-in Piling Method for its low noise and almost no vibration advantages.BackgroundThe East Garden Grove-Wintersburg Channel is part of the Orange County Flood Control District (OCFCD) and is operated and maintained by OC (Orange County) Public Works (see Figure 1 for its location). The channel, referred to as OCFCD facility # C05 (C05), had suffered significant toe undercutting and slope erosion of its levee due to a series of storms. These began after the facility was constructed in the 1960’s and culminated in 2005. Consequently, the levee was deemed significantly deficient and was eventually declared as a local emergency in 2007. C05 was an incised channel and its levee was constructed primarily from native materials. Operation and Maintenance (O&M) personnel notified the design staff at OC Public Works to be aware of major consequences associated with the dilapidation problem in the most downstream reach of the channel in the vicinity of the Bolsa Chica Wetlands Restoration Project. In 2007, the Orange County Board of Supervisors declared a local emergency to fix the levees with sheet piles to be driven by the Press-in Piling Method, hydraulic pushing piles into ground by holding onto previously installed piles. The project that ensued represented the first in-tandem use on the West Coast of the United States of the Press-in pile driver with its GRB System (Press-in pile driver, a support crane and pile transporter travel on top of already-driven sheet piles). This is further discussed in this paper in the sections titled “Press-in Piling Method” and “GRB System”, respectively. The project repaired approximately 3,800 feet of erosion on the north levee of C05 with 45-foot long cantilevered sheet piles. The sheet piles design constraints are discussed in this paper in the section titled “C05 2008 Emergency Sheet Pile Project (Phase 1)”. Between 2012 and 2014, another mile’s worth of levee reach was improved with the Soil-Mix-Sandwich (SMS) Method. This concept consisted of deep soil cement mix (DSCM) columns sandwiched within the dual rows of sheet piles. Additional details on the SMS, its DSCM construction, and its hybrid geo-structure design concepts are well beyond the scope of this discussion, which is primarily focused on sheet piles. Instead, the interested reader is referred to two papers on the SMS and its DSCM metrics (Fayad, 2015; and Arora, et al., 2015). These were presented and published in the Proceedings of the Deep Foundations Institute (DFI) 2015 Conference on Deep Mixing. Hence, in the section of this paper titled “C05 SMS Dual Sheet Piles Project (Phase 2)” only the sheet pile design constraints of the SMS are covered. Finally, in the area where the project traversed the Alquist-Priolo zone of the Newport-Inglewood tectonic fault, an expandable and deflectable sheet pile wall was used to isolate the flood channel from the Bolsa Chica wetlands. Its details are addressed in the section titled “C05 Accordion Sheet Pile Wall (Phase 2)” of this paper."

Jan 1, 2017

By Peter A. Cain, John C. Folinsbee

"A 4-ft.-diameter shaft has been drilled to a depth of 2,790 ft. in strong, hard, basic Precambrian rocks at Lynn Lake Manitoba. This was done on the property of Sherritt Gordon Mines Limited for the purpose of ventilating and developing the ""N"" orebody, which is located approximately 4,000 ft. south of the Farley shaft.The drilling was done under contract by two drilling companies. Peter Bawden Drilling (1964) Limited drilled the initial 12:1,4-in. pilot hole to a depth of 3,000 ft. Shaft Drillers Limited of Canada then reamed the hole to 4 ft. in diameter to a depth of 2,790 ft. At this point, the reaming was stopped because of the difficulty in passing a change in direction in the line of the pilot hole. The hole was completed by driving a raise 200 ft. from the 3000 level to the bottom of the 4-ft. hole using an Alimak raise climber.Cuttings from the reaming operation were directed into the 12:1,4-in. pilot hole, where they fell to the 3000 level and were removed by a mucking machine and standard mine development cars.The elapsed time from the start of the pilot hole to the completion of the reaming operation was ten months, with an average advance of 279ft. per month. There was a two-month delay between the completion of the pilot hole and the start of the reaming operation.The 12:1,4-in. hole was drilled in an elapsed time of 45 days from the time of setting up the rig. The average advance per day was 66.8 ft.The reaming operation was done in an elapsed time of 194 days. A one-month delay required to repair damaged equipment left 163 days for the drilling and setting-up operation, for an advance per day of 17.1 ft."

Jan 1, 1966

By Patrick E. Cavanagh

"A pilot shaft furnace was operated for one year at Steep Rock to produce special high-grade products from coarse ore, using lignite as fuel. The furnace is 10 ft in diameter and 60 ft high. When operated to heat coarse Steep Rock ore to drive off combined water and give a 64-per-cent-Fe product, the fuel consomption was 900,000 Btu's per long ton of product. The furnace was run in this way from September 1966 to January 1967 to establish the technique of feeding and discharging the furnace and controlling the gas composition and temperature. The furnace is similar in operation to a lignite water gas producer containing a large proportion of catalytic iron oxide. Steam injection is used to control the temperature. The product was tumbled in a rotary trommel to stabilize it. The resulting fines could be fed to the conventional pellet plant at Steep Rock. The furnace was next operated to make 77-per-cent-Fe metallized coarse ore. Several major modifications in de-sign were made and the furnace was successfully operated for short periods to maintain the required conditions to remove 75 per cent of the oxygen from the ore to give a 75-per-cent-reduced product at a grade of 77 per cent iron. The furnace cooling zone was operated under positive pressure, with internai alkaline water sprays to cool the charge. The product was discharged from the open bottom of the furnace without serions reoxidation. The metallized ore was magnetically separated from the discharge. Most of the charred lignite discharged along with the ore is re-cycled. Fuel requirement was 11,000,000 Btu's per long ton of product. This metallized coarse ore is intended for blast furnace feed. A short test run was carried out to establish the conditions for making a highly reduced melting stock for steel furnaces. To achieve 90 per cent reduction and over 90 per cent Fe, the furnace must be slowed down so that the production rate is about one-half the rate when making a 75-per-cent-reduced metallized product. Fuel requirement is 15,000,000 Btu's per long ton of product. The simple shaft furnace developed is similar to the top half of a blast furnace, with some major modifications to allow discharging into the open air. This Low Temperature Blast Furnace program has been technically successful and has resulted in making data available for the design of a commercial plant. Study of the commercial feasibility of large-scale production of metallized coarse ore at Steep Rock is still continuing."

Jan 1, 1968

By R. K. Koch

The Bureau of Mines developed a zircon sand molding process for static casting of small titanium or zirconium shapes. Castings with unfinished weights up to 3.5 kg (7.7 lb) were produced in an inductoslag furnace and castings up to 7 kg (15.4 lb) were poured in a consumable electrode skull-casting furnace. Molds and cores were made by ram-molding, foundry-grade zircon sand (AFS gfn 93 to 95) bonded by grade D waterglass and tempered with water. Molds and cores were cured either at 250° C (482° F) or 900° C (1,652° F). Castings from the higher temperature molds broke cleanly from the sand while the lower temperature molds produced castings that had to be cleaned by sand-blasting. However, low-temperature cured molds and cores have a number of advantages as follows: (1) A faster, less energy-consuming curing cycle is used; (2) expended cores are water soluble which greatly facilitates core removal; and (3) enough of the binder in crushed expended molds is reactivated by temper water so that the molding mix can be reused five times without any fresh binder additions and up to twenty times without exceeding a total cumulative binder addition of 52 ml/kg dry sand. Crushed used molds that had been cured at 900° C had no detectable binding strength when mixed only with temper water. A large number of oxide and silicate mold washes were studied for improved casting integrity. The most effective wash found for zirconium or titanium casting was monoclinic zirconia (325 mesh).

Jan 1, 1977

By N. Mulaudzi, S. Archer

"Direct cobalt electrowinning was developed to produce unrefined cobalt metal as an alternative to producing a mixed hydroxide product (MHP), which is the common cobalt intermediate product in African Copperbelt operations. MHP is preferred due to the high cost of producing high-grade cobalt cathode. Direct cobalt electrowinning test work results have shown that the purity of the unrefined cobalt metal produced from a low-grade copper solvent-extraction raffinate stream was ~97% (w/w), which is significantly higher than the MHP purity (up to 45% (w/w) Co). The current study investigates whether direct cobalt electrowinning would increase the profitability of African Copperbelt copper–cobalt oxide operations, when compared with the MHP flowsheet. An order-of-magnitude economic evaluation was conducted using dynamic differential discounted cash flow models on a “bare-bones” basis, using a 10% discount rate. Three variables were evaluated, namely; reagent utilisation extents, precipitation extents and filter-press wash efficiency. Multivariable risk analysis was also conducted using the Monte Carlo simulation technique to understand the impact of key project drivers. The financial study results indicated that a direct cobalt electrowinning flowsheet could potentially result in a higher mean net present value (NPV) compared with the MHP flowsheet. Cobalt recovery was found to have the most significant impact on the NPV. In addition to increased profitability of African Copperbelt operations, direct cobalt electrowinning has the potential to reduce the environmental footprint of operations as well as addressing the Democratic Republic of Congo government’s drive towards export of higher value metal products instead of low-grade intermediates."

Jan 1, 2015

By H. Dolezal

A laboratory study of acid-ferrous sulfate treatment of low-grade manganese ores from the Cuyuna range, Minnesota resulted in 93-percent extraction of manganese as manganese sulfate with consumption of 3.8 pounds of H2S04 per pound of extracted manganese. Two types of ore were treated in consecutive stages. The first are contained carbonate minerals of manganese and iron, both soluble in H2S04 solution. The second ore contained manganese oxide minerals, insoluble in straight acid solution but soluble in the ferrous sulfate solution obtained from treating the first ore. Leaching data were obtained by countercurrent percolation of coarse (minus-1/2-inch) ore particles at room temperature and by agitating minus-65-mesh ore particles in heated solution. Extraction of manganese and acid consumption were the same, but the percolation leach required 6 days compared with 1 hour for hot agitation. Variations in the size of ore particles treated, leaching time, acid concentration, solution temperatures, and method of applying ferrous sulfate solution to the oxide ore were studied. The effects of several reagents for removing iron from solution and improving filtration were also studied.

Jan 1, 1959

By J Janus, J Krawczyk

Local accumulation of methane in workings of a longwall is one of the most common causes of mining accidents. This gas has many sources: it may leak from goaf through permeable sealings, or through gaps between roof support sections. This stream is then mixed with ventilation air. In the case of auxiliary ventilation ducts, or free jet fans, we have to consider the propagation of a clean air stream in areas with an air-methane mixture. Therefore, modelling the mixing process of methane with ventilation air is important for determining the hazardous areas and thus to ensure safety. Computational fluid dynamics (CFD), specifically the finite volume method, provides tools for such modelling. However, this method requires validation. For this purpose, we have compared measurements with simulations for selected test cases having sufficient similarity to the present problems. In typical methane explosion hazard areas, such as a longwall, it is difficult to make measurements sufficiently to confirm credibility of 3D CFD simulations. As a relevant alternative, an injector methane drainage station placed in an underground gallery has been selected. The stream of drained goaf methane is entrained by compressed air powered injectors and then mixed with ventilation air. Research in this area does not interfere with mining operations, it can be performed safely in a repeatable way. Flow within the site has many similarities to conditions in mine drifts of the longwall area. Comparative research of measuring the methane concentration distribution in the mine drift downstream injector station, with simulations of propagation of the methane stream, was carried out. For measuring the methane concentration distribution in the mine drift a multipoint measurement velocity system developed at the Strata Mechanics Research Institute was used. For the simulation a finite volume method for turbulent flow of gas mixtures was applied. Preliminary results of comparison are shown as graphs and tables.CITATION:Janus, J and Krawczyk, J, 2013. An analysis of the mixing of air and methane in the stream produced by the mine injector station - Presenting preliminary results of measurements and modelling, in Proceedings The Australian Mine Ventilation Conference , pp 49-56 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013