Search Documents

By S. Vivek

An Atomic force microscope (AFM) was used to measure the surface forces between hydrophobic silica surfaces. The measurements were conducted in the presence and absence of Cu(II)species in solution to study the effects of the cation adsorption on the hydrophobic force. The results obtained in the absence of the Cu (II)species showed that the hydrophobic force does not change with pH, while the electrostatic repulsive force changes substantially with pH. In the presence of the Cu(II) species, the hydrophobic force begins to decrease at a pH where Cu2+ions are hydrolyzed, indicating that the first hydrolysis product (i.e., CuOH+ions) are the species adsorbing on the surface of the hydrophobic silica. The results of the surface force measurements were used to develop a model for the adsorption of the hydrolysis product of Cu(II) species on the hydrophobic silica.

Jan 1, 2003

By A Satyanaga, H Rahardjo, K G. Mercer

The soil-water characteristic curve (SWCC) is one of the most essential soil properties in unsaturated soil mechanics. The water flow and storage characteristics of an unsaturated soil are closely related to the amount of water contained in the pores and the negative pore-water pressure in the soil. These are both in turn, related to the particle-size distribution and the plasticity of the soil. The SWCC is obtained by laboratory testing which is difficult to perform, costly and time consuming. There is a significant advantage in establishing typical SWCC envelopes for different soil types from a geotechnical design and analysis viewpoint. This paper presents some of the research work undertaken by UWA and NTU to develop SWCC envelopes for soil types classified in terms of the ASTM D2487 Unified Soil Classification System (USCS). This was done by establishing a large database of soils from across the world, classifying them according to ASTM D2487 and undertaking SWCC testing for each soil. This paper presents the SWCC test results from a selection of three of the most common soil classifications encountered in geotechnical engineering practise.CITATION:Mercer, K G, Rahardjo, H and Satyanaga, A, 2018. The development of soil water characteristic curves for soil types classified according to the USCS, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 263–273 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By C. J. Martin, M. P. Hay

"A methodology was developed in the mid-1980’s to predict plant performance from standard laboratory flotation tests. The technique is based on a simple, empirical kinetics model, and is tailored for use by the practical metallurgist.To date the performance of more than 20 flotation plants has been predicted, including copper, lead, zinc, phosphate, pyrite, graphite, cassiterite, platinum, nickel and various slags. The method has successfully been used to predict and size four flotation plants directly from bench-scale laboratory flotation testwork. All have since been commissioned, and have performed as predicted.The technique has now received broad acceptance within the South African mining industry, for example in the last year alone it has been used to drive flowsheet development for at least seven new plants. It is also being used to assist in the optimisation of existing operating plants.The methodology is described in this paper and verification of the methodology is presented using case studies of porphyry, polymetallic and PGM operations.INTRODUCTIONThere is considerable interest these days in the use of modelling to simulate flotation circuits, for process design and plant optimisation purposes. Although these models are proving to be useful tools for plant design and optimisation, their complexity can make them cumbersome – expensive to use and difficult for metallurgists to visualise and mentally absorb, without a background in each specific technique. In “SUPASIM” no attempt is made to measure flotation fundamentals, rather to use empirical relationships between laboratory flotation kinetics and plant performance – relationships that hold up well to validation exercises as will be demonstrated later in this paper. Although not designed to be as comprehensive as other models, “SUPASIM” is easily understood by the operating metallurgist and can be quickly and easily applied."

Jan 1, 2004

By Xiao-hui Fan, Li-shun Yuan, Xu-ling Chen, Wei Lv, Min Gan, Yi Wang

"As the amount of ferrous scrap increases every year, it becomes more and more urgent to deal with this iron-bearing resource properly. This paper puts forward a method on resource-oriented utilization of ferrous scrap (cold-bonded pelletizing), and these cold-bonded pellets can be used as coolant in a converter. The influence on the pellets qualities by using different kinds of chloride as rust agents is studied, and results show that the strength of cold-bonded pellets increases significantly by using a combination of the three kinds of chloride -NaCl,MgClz,FeCh, their best dosages are 1.2%, 0.2%, 0.1% respectively. Other iron-bearing materials also have an effect upon the pellets strength, by adding 5% iron powder and maintaining for 48h, the compressive strength of the clumps surpass 2500N/A, dropping strength surpass 4 times/ A, and 10% iron slag or 20% steel slag can replace 5% iron powder while obtaining the comparative quality. The influence of different ratios of three ferrous scrap (converter mud, iron scale and dust) is further studied, and results show that when the ratio is 30% : 30% : 40%, the pellet strength reaches the maximum. After maintaining for 24~48h, the clumps can meet the mechanical as well as the physical-chemical requirements as BOF steelmaking refrigerant.IntroductionGreat amounts of converter mud, dust and iron scale are produced in steel production process. These materials are of great values, and their accumulation not only leads to environmental pollution, but also wastes the precious resources, which restricts the sustainable development of the steel industry [1,2] The main approach at present to dealing with the ferrous scrap is to add them into sintering. But in this way, the utilization factor of sintering and the quality of sinter decline while the energy consumption increases [3].Therefore, more advanced and efficient technology is needed to make the best of these iron resources. Cold consolidation of ferrous scrap is a simple process that has many advantages such as less investment, quicker effect, lower energy and lower cost [4-5] But the conventional maintaining period is too long, usually up to four-six weeks, and the pellet strength is low. Therefore, the key points of the cold-bonded pelletizing are to develop a new adhesive [4,5] to shorten the natural maintenance cycle and to improve the strength of the pellets. A method on resource-oriented utilization of ferrous scrap (cold-bonded pelletizing) is brought forward, and these cold-bonded pellets can be used as coolant in converter. After maintaining for 48h, these cold-bonded pellets can satisfy the mechanical requirements to replace the converter coolant [6]."

Jan 1, 2013

By C. K. Kocsis

A study was undertaken to evaluate the thermal environment and determine the contributing heat sources within the existing 153 Orebody of Coleman/McCreedy East Mine which would then enable the prediction of the climatic conditions in the mine?s future 170 Orebody. The study entailed continuously monitoring, for a 2-week period, the dry-bulb temperature, humidity and barometric pressure along the existing intake airways from surface down to the 4810 Level and throughout an active mining area on that level. Furthermore, the mining activities and associated equipment that could be responsible for any changes in the temperature and humidity conditions within this mining area were also monitored. These data were then used to develop and validate a climatic simulation of the mine?s mechanized cut and fill mining method. This climatic model was then transposed to the future 5700 Level in the deeper 170 Orebody, to determine the environmental conditions within its production workings and along the main haulage route ascending from that area. Based upon the simulations performed it was shown that the level of ventilation planned for the new orebody should be able to maintain adequate environmental conditions. However, this study did emphasize the importance of the appropriate distribution of airflow in workplaces that used auxiliary ventilation in order to sustain a suitable thermal environment.

Jan 1, 2009

By Charles Sabine

The U.S. Bureau of Mines studied mines and prospects in the Bristol/Granite Mountains Wilderness Study Area (WSA) in 1982. The 45,000 acre WSA, located in the eastern Mojave Desert of California, is underlain by Mesozoic plutonic rocks with scattered roof pendants of Paleozoic (?) metasedimentary rocks. Two mines and six prospects are identified; one mine, the Silver Lode Mine, and a prospect of unknown name are adjacent to the area. The Silver Lode Mine has occurrences of silver, lead and zinc. Within the study area, the Comanche Mine has occurrences of iron and copper and the Iron Victory Prospect has an occurrence of iron. None are large enough to constitute a resource. Occurrences of magnesian marble at the Comanche Mine, Iron Victory Prospect, and elsewhere in the area contain too much MgO for commercial use other than agricultural soil supplements or crushed stone. Transportation costs to markets would exceed the value of the rock. At the Comanche Mine, situated in a roof pendant of marble, about 10 tons remain of a 110-ton pod of magnetite which contained 42.5% iron, and less than 50 tons remain of a mineralized fault breccia which averaged 2.5% copper and 0.3 oz/ton silver. Magnesian marble contained 41 to 45% CaO and 14 to 16% MgO. Primary and secondary silver, lead, zinc, and copper minerals are disseminated along altered joints and in quartz veins in quartz monzonite at the Silver Lode Mine, adjacent to the WSA. Analytical data are sporadic; samples contained as much as 0.12 oz/ton gold, 1.8 oz/ton Silver, 1.1% lead, 3.8% zinc, and 0.3% copper. Mineralized zones in the workings are not resources, but they might indicate possible silver-lead-zinc resources at depth. At the Iron Victory Prospect, lenses of magnetite and hematite with some chalcopyrite occur in a skarn lone in a marble roof pendant. About 110,000 tons of iron-rich rock, averaging 47.2% iron, are present; the largest lens contains about 30,000 tons. About 150,000 tons of magnesian marble, averaging 41.0% CaO and 11.7% MgO, are also present. Deposits of stone, and sand and gravel in the WSA are too distant from markets to be resources. Occurrences of energy minerals were not identified.

Jan 1, 1984

By Paul W. Weiblen, Louis J. Cabri, Rolando Lastra

"Preliminary tests were done to determine whether comminution by electric-pulse disaggregation, or EPD (cf. Rudashevsky et al; 1995), was more effective than using conventional crushing for Merensky Reef ore. A hand sample of the Merensky Reef was sawn in two: then one sub-sample was comminuted to – 2 mm using E-PD at the University of Minnesota, and the other sub-sample was crushed to –2 mm using a conventional jaw crusher at CANMET.The products of the electric-pulse disaggregation and jaw crusher were fractionated by sieving and by a separation using a heavy liquid with a specific gravity of 3.3, because the proportion of platinum-group minerals (PGM) and sulphides to silicate minerals is very low. Thus, four mineral separates were produced: –2000 + 833 µm, -833 +208 µm, -208-µm float and -208-µm sink. All the mineral separates were studied by image analysis (Lastra et al; 1998). The main objective was to determine the liberation of gangue (silicate minerals), chromite, pyrrhotite, chalcopyrite, pentlandite and PGM. In the case of the PGM, a specific image analysis program was written to search and measure these minerals."

Jan 1, 2003

By O. Q. Leone

A processing unit was developed for the complete cleaning of titanium alloy chips. The process uses solvent degreasing, magnetic separation, and anodic solution of nonmagnetic impurities in 10 weight-percent sulfuric acid. Vacuum arc-melted ingots weighing approximately 10 pounds each were prepared from cleaning chips according to ingot specifications.

Jan 1, 1973

By W. P. Johnstone

The computer assisted generation of geological models to represent the geometry of, and grade distribution within, orebodies is a rapidly growing area of the geological profession. Such models are increasingly used as a necessary starting point in determining the mineability of mineral deposits in terms of practical mine design and economic considerations. The transition from traditional techniques such as field or underground mapping and the manual calculation of grade and tonnage estimates, as well as related activities such as the interpolation of cross-sections, the use of stereographic projections, core logging and hand contouring, to computerized applications, is by no means complete. In fact, many geological professionals deliberately avoid the use of computer simulations based on the perception that the resulting models are simplistic and that their construction is not founded on sound geological principles. The purpose of this paper is to assess current thinking on this topic by considering; (a) an overview of advances in the drafting of geological maps, (b) the theoretical basis for multi-dimensional geological modelling, (c) the case for combining traditional and modern techniques, and (d) the benefits to the mining value chain.

Jan 1, 2003

By Steven W. Schmauch

A mineral survey by the U.S. Bureau of Mines and U.S. Geological Survey indicate the Blanco Mountain RARE II area has low potential. Lode deposits consist of small, mineralized quartz or quartz-gossan veins. The veins are sparse and widely separated and lead, silver and gold content is restricted in amount and concentration. No gold or other potentially economic minerals were found in a placer deposit. There is no evidence of industrial mineral, geothermal, or energy resource potential in the study area. INTRODUCTION A mineral resource survey of the Blanco Mountain RARE II area (No. 5059), Inyo and Mono Counties, California was conducted in July 1981. This report summarizes the results and interpretations of the Bureau of Mines investigation.

Jan 1, 1982

By Darelle T. Janse van Rensburg

Some of the more recent developments in Paint Technology are solvent free materials. These coatings have mainly been formulated to overcome the negative attributes of solvent-based coatings, i.e. environmental, safety and health risks, potential for solvent entrapment and osmotic blistering, as well as the formation of micro-pores during the curing process. Two solvent free liquid epoxy coatings have been used extensively on power generation plant. However, very little is known regarding their long-term performance under different exposure conditions, as well as whether these coatings actually perform better than their solvent-borne counterparts. In addition, solvent free materials are generally used where outage periods are restricted and coatings need to be applied within a very short period. Though these materials have reportedly much shorter curing times than other conventional solvent-borne coatings, little is known regarding their limits with respect to maximum film thicknesses and being put into service while still being wet/partially uncured. The latter has become common practice at many power stations in the past two years or so. In addition, the application and curing methods of solvent free materials are different to that of solvent-borne materials, and may require equipment and application process changes. This paper covers the application and performance properties of solvent free coatings in comparison to solvent-borne materials primarily intended for immersion service. Numerous coatings were evaluated under immersed static and cyclic hydrostatic pressures. Other tests included short curing / early immersion tests, dry-to-touch and dry-through curing times, adhesion tests, surface tolerance tests, etc. The results show that the solvent free materials have clear benefits with respect to safety, health, environmental and long-term performance, but will be more difficult to apply compared to solvent-borne materials.

Jan 1, 2006

By Samer R. Rabab?ah

As part of the PHX Sky TrainTM project at Phoenix Sky Harbor International Airport in Phoenix, Arizona, the existing traffic lanes at the 44th Street underpass below the Union Pacific Railroad (UPRR) Bridge will be shifted to accommodate the people mover guideway. The proposed reconfiguration and reconstruction of 44th Street required the utilization of micropiles and permeation grouting to resist the lateral forces induced by cutting into the slope below the existing bridge abutment footing. This paper discusses the evaluation of the existing bridge abutment, including analysis of the original foundation system, and design, installation and testing of a new micropile-supported retaining wall to support the cut slope below the existing bridge abutment foundation. A monitoring program was implemented during construction to evaluate the short- and long-term performance of the bridge abutment. Instrumentation included survey monitoring points, inclinometers, tiltmeters and crack gauges. A micropile load testing program was conducted to verify design assumptions concerning micropile axial and lateral loading. Numerical analyses (using PLAXIS software) were performed to predict the short- and long-term behavior of both the abutment wall and the bridge foundations. Movement data collected from the monitoring program indicate that the wall and bridge foundations are performing satisfactorily and within the general bounds of predicted movements. The results from the numerical modeling using PLAXIS software showed that the proposed solution is deemed adequate to provide the needed global stability with an acceptable factor of safety, along with acceptable deformation.

Jan 1, 2011

By J. D. Noll, S. E. Mischler

Measurement and sampling of diesel particulate matter in mine air presents a challenge due to the complexity of the diesel aerosol. The results of a series of tests carried out by the National Institute for Occupation Safety and Health, Pittsburgh Research Laboratory, in an underground mine were used to evaluate several measurement methods that are currently used to characterize particulate matter emitted by diesel-powered equipment. This paper presents an overview of these techniques and examples of the results along with a discussion of the advantages and information gained by each technique. The measurement methods discussed include particle size measurements using a scanning mobility particle sizer, total particulate matter measurements using a tapered elemental oscillating microbalance, a size selective sampling method for workplace and personal exposure assessment and a size-selective high volume sampling method for carbon analysis.

By B. S. Fee, R. R. Klimpel

"Froth flotation is the most widely used and economic means of concentrating metal sulfide ores such as those containing copper, lead, zinc, nickel, molybdenum, and pyrite. Also recoverable are other metal species that are often associated with sulfide ores such as cobalt, platinum, gold, silver, etc. Most of the initial developments made with the process of froth flotation in the early 20th century were based on the processing of metal sulfide ores. It is the relative technical and economic ease of floating metal sulfide minerals with small amounts of appropriate frothers and sulfur containing (thio) collectors that has been a major economic driving force behind the rapid expansion in the supply of metals such as copper, lead, zinc, and nickel that has occurred in the world's economy in the last 50 years. This author estimates that 1.6 billion tons of sulfide ores are processed each year (1980) in the free world based on the froth flotation process.While there has been a tendency for the quality of metal sulfide ores in any one geographic location to deteriorate over time due to mining intensity, the overall global supply of sulfide minerals is still very large. Thus, the physical supply side of sulfide ore concentrates has not been under strong technology improvement pressure with increasing metal demands. Part of this is due to the ability of capital to consistently move to new geographic locations having suitable grade sulfide ores. In these moves, the actual froth flotation technology used (including collector chemicals) has had to change little. As an illustration of this trend, of the approximately 80,000 metric tons of thio collectors used commercially (1980) in the free world, almost 98% were known and manufactured in some form 25 years ago (1). This is clearly not typical of reagent development in other process related industries. In addition, the industrial scale practice of froth flotation applied to sulfide ores has proceeded since the 1920 s with often little direct (predictive) scientific explanation due to the extreme complexity of the flotation process. Empirical testing has been a mainstay of industrial flotation reagent development and use. Even today there is often strong disagreement between researchers as to the mechanisms of chemical flotation practices that have been performed successfully at an industrial scale for many years."

Jan 1, 1987

By Richard Campbell

Effective strata control, utilising fully encapsulated resin grouted roof bolts is dependent on the installed quality of the reinforcement elements. Resin based grouts are the main form of rock bolt anchorage in the underground coal industry in Australia and New Zealand. To be effective the system requires the mixing of the catalyst and mastic components of the resin as well as shredding of the cartridge that contains the resin. Over the past six years Solid Energy New Zealand Ltd (SENZ) has pioneered an extensive work programme quantifying the effects and extent of poor installation quality due to gloving, poor mixing and loss of encapsulation (Pastars 2003, Campbell et al 2003, Mould et al 2004, Campbell et al 2005 and Pastars & MacGregor, 2005). The One-Step Bolt (OSB), an innovative bolting solution designed and manufactured by Hilti Pty Ltd offers a self drilling, single pass bolting method that eliminates gloving, guarantees mixing quality and encapsulation performance of the installed product while not jeopardising the mechanical performance of the bolt. This paper details recent work undertaken by SENZ designed to understand and quantify the system performance of the Hilti OSB in New Zealand?s thick coal seam mining environments.

Jan 1, 2006

By G. V. Krishnan, L. Adler

A rock classification for drilling and boring is presented covering most equipment types and providing an estimation of the key parameters for operation, such as thrust and speed, and of performance such as penetration rate and bit life. Drilling and boring are significant and integral aspects of both the mining and heavy construction industries. Together these constitute over 20% of the G.N.P. Drilling and boring represent the most arduous mechanical processes performed in industry. Their misapplication quickly leads to equipment destruction, hazards, and to major delays. The classification is unified in two ways: 1) for a particular rock class several parameters can be estimated, 2) the classification integrates most excavating activities (i.e. digging, ripping and even blasting), and is derived from ground control. The rock classification provides a job property, based on fundamental and index properties, which yields quick and rough estimates of vital information. However it does not obviate the need for a more thorough analysis, and maintaining field records. BACKGROUND In order to adequately describe a drilling operation the conditions, activity, and equipment must be characterized. Of these the major independent variables are the conditions. Conditions focus on the geologic mass and also consider whether the site is surface or underground. The primary component of the geologic mass is the rock type, detailed below in Rock Characteristics. The other components

Jan 1, 1983

By Valerio Viti

In High Pressure Die Casting a molten metal is injected through a thin gate into the cast cavity. High injection pressures and high gate velocities create atomization phenomena which can negatively affect the final quality of the cast. In order to control atomization process it is essential to understand the atomization patterns and the two-phase flowfield that exist at the gate exit. In the present work, 2D numerical simulations of the flow of molten Magnesium through a high aspect-ratio rectangular gate are performed using a water analogue for an open and closed cavity. The numerical simulations made use of VOF-type (Eulerian) physical models and Lagrangian models. Further, a sub-grid scale model was implemented that, in conjunction with VOF-type equations can efficiently predict the general atomization pattern without the need for high-resolution grids. The numerical results were compared to experimental data for validation.

Jan 1, 2006

By Peter Van deVelde

Many companies in North America because of economic or environmental reasons are considering reprocessing material from their waste ponds. The Japanese have developed highly specialized machines and techniques to reprocess industrial/mining wastes from settling ponds. This paper discusses the techniques and results of applying this technology to North American applications.

Jan 1, 1983

By J. Vance Batty

The Permian Red Bed copper deposits of the South Central States are a potentially important resource. Only the higher grade, near-surface ores are now exploited because conventional froth flotation does not recover oxidized copper minerals which comprise 10 to 15 percent or more of the copper content of typical ore. Laboratory-scale beneficiation studies were initiated to devise a method capable of recovering both sulfide and oxidized copper mineral. Testing established that the high clay and gypsum content of typical ore prevented effective flotation of the oxide mineral using sulfidizing, fatty-acid, or oil emulsion techniques. A modified leach-precipitation-flotation (L-P-F) procedure recovered over 90 percent of the copper, compared to a recovery of 77 percent obtained by conventional sulfide flotation. The higher costs of the L-P-F method would reduce the increased revenue from higher copper recovery. An increase in copper price and/or an increase in oxide copper content of the ore would make the L-P-F process comparatively more attractive.

Jan 1, 1970

By Larry G. Stolarczyk

Jan 1, 1980