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By Shaw-Shong Liew

This paper presents the design concept using floating piles to support 2500Ton oil storage tanks on a very soft alluvial clayey soil of about 40m thick in Riau Province of Sumatra, Indonesia. The floating piles of various penetration lengths were designed to support seven numbers of such storage tanks seating on a 20m diameter and 500mm thick reinforced concrete (RC) circular raft. The pile points have been strategically located at the RC raft. Varying pile penetration lengths have been designed to minimize the angular distortion of the thin RC raft and the out-of-plane deflection at the tank edge. Vibrating wire strain gauges were installed at different levels inside the ø350mm prestressed reinforced concrete piles to measure the load transfer profile during the static load tests and water-loading test. The installation and interpretation of the instrumentation are described and discussed. Boreholes, in-situ tests like piezocones, vane shear tests and standard penetration tests, and laboratory testing were carried out to obtain geotechnical parameters for the pile designs. Static load tests were also carried out on the spun piles of varying lengths of 24m, 30m and 36m respectively. It has been demonstrated that the floating pile system can be a cost effective design to support heavy structures on very soft compressible deposits with satisfactory performance. Finally, the design concept validated with the results of instrumentation is discussed.

Jan 1, 2002

By E. Baliktsis

We have searched and analyzed several modern technologies aiming at the best applications of environmental management, the studying of quarrying ? mining as well as the excavation sites ? utilization ? rehabilitation. We have used long-range reflectorless laser surveying systems, so as to achieve the fastest and most accurate surveying of the extractive work sites. We also used them, in order to collect field data, measure distances, surveying monitoring stations and environmental parameters ? data. Furthermore these systems can make the field work quite faster, more reliable and credible and have low cost in collecting data even in dangerous and non-approachable areas. We have used and processed on the field data in G.I.S. applications, in order to create 2-D and 3-D digital ground models. These G.I.S. applications present the existing relief and the management of the final stage of the area. The suggested techniques and works needed, for reclamation and utilization of the areas, could be tried, evaluated and well presented. The evolution and utilization of these ?smart? modern tools for the effective environmental management of quarrying ? mining ? extractive activity sites, will be presented by using case histories from the Hellenic territory.

Jan 1, 2002

By F. Repmann

Waste-dumps originating from the mining industry constitute a serious environmental problem if they are not properly rehabilitated. Industrial and domestic sewage sludge from waste water purification plants on the other hand constitute a problem of environmentally acceptable disposal as these residues contain a large number of potential contaminants. The current project aims at developing an integrated methodology to rehabilitate the mining waste-dumps by the use of sewage sludge so that the two mentioned problems will be solved at once.

Jan 1, 2002

By Mark Kuchta, Hans Engberg

The Swedish mining company LKAB operates two of the largest underground mines in the world today that together produce around 35 Mton of iron ore per year. During the 1990s, the company embarked on a massive effort to computerize its mine planning system. The goal was to combine various mine planning operations including mine surveying, geologic modeling, mine layout, production planning, and production follow-up into one modular based integrated system. The system was built around a large Oracle database and the Microstation CAD system. This overall design strategy and the various system modules are described, and some experiences gained using the system are discussed.

Jan 1, 2002

By T Gready

Stawell Gold Mines operates the Magdala underground mine in western Victoria, Australia. Several orebodies are extracted by longhole open stoping at a depth of 900 m below the town of Stawell. Some stopes are backfilled with cemented slurry rock fill (CSRF) to ensure stability, increase recovery of ore reserves, minimise dilution of ore grades, and add value to the project. StawellÆs simple CSRF system is described, including the novel equipment used to minimise capital costs. Design criteria, operating procedures, monitoring systems and results are discussed in detail. Practical aspects are considered, including lessons learnt about barricades, overbreak and segregation. The economics of CSRF are discussed, including capital costs, operating costs and the total cost per ounce of gold poured. Options for mining with and without CSRF are compared in terms of return on investment and net cash flows. Examples demonstrate the method used to calculate æbreak-evenÆ stope ore grades which determine whether or not CSRF will add value in different circumstances.

Jan 1, 2002

By Ali Bouafia

Five full-scale horizontal loading tests of piles carried out by the LCPC in France are interpreted in order to analyse P-Y load-transfer curves. The experimental piles are either bored or jacked into quite homogenous sandy soils and instrumented by strain gauges for measuring bending moments along the pile. Successive differentiation and integration of bending moment profiles have led to derive respectively lateral soil reaction and displacements then to construct the load-transfer P-Y curves. The initial horizontal lateral reaction modulus was derived from these curves and shows linear variation with depth in accordance with Gibson soils profiles. P-Y curves are validated by back-computation of the pile on the basis de these curves and the horizontal reaction modulus was compared to the recommendations frequently used in pile design practice.

Jan 1, 2002

By B. Samanta

Abstract - Ore reserve estimation, based on sparse drill hole data, was conducted for a placer gold property in Nome, Alaska. A problem with sparse data is that random subdivision of the data into modelling and evaluation subsets (as is commonly done) becomes a problem, as random selection may result in biased/skewed subsets. Therefore, a technique that combined data segmentation with genetic algorithms (GA) was applied to divide the samples into three equivalent subsets: training, validation and testing. Data segmentation was done on the basis of the distribution of gold values. Neural network and a variety of kriging techniques were used to estimate gold grades. A multi-layer feed forward neural network along with "early/quick stop" training was used for neural network modelling. A comparative evaluation of kriging and neural network methods was then performed. The results revealed that neural network was generally superior to the kriging techniques for gold grade estimation in the Nome deposit.

Jan 1, 2002

By C. Swart

Automation technologies are increasingly adopted in different mines world-wide. This paper presents the technical aspects of vehicle automation applications at two Noranda operating mines. Teleoperation of 5 LHDs at Noranda?s Bell Allard mine is used in order to meet aggressive mining requirements under difficult conditions. The equipment is performing under high demand for reliability and performance. In order to further increase performance, automated loading has been commissioned on one of the LHDs and is being tested. Results to date indicate improved performance with respect to an operator through better filling of the bucket, fewer passes at the muck pile and shorter cycles. Noranda?s Brunswick mine is currently commissioning an automated haulage zone where two optically guided trucks transport ore from a remotely operated chute to two ore passes. Expected operational advantages include increased system capacity and enhanced safety and comfort for the operator. Monitoring to date indicates that the trucks can operate reliably under the conditions imposed by mine production.

Jan 1, 2002

By Yi Luo

Accurate mechanical and geological information of the roof strata is vital for roof bolting design in underground mines. In order to obtain such information in a timely manner, a research has been under way to develop a technology for mapping the roof geology using the drilling parameters acquired during the roof bolting operations. In this paper, a systematic approach has been proposed for determining the rock strengths using the acquired real-time drilling parameters. A computer simulation program based on the mathematic model has been developed to verify the approach and to study its sensitivity. The method has been used to interpret the acquired drilling data.

Jan 1, 2002

By A. Martin

Detailed porewater profiles of arsenic and other interstitial metabolites were used to assess the relationship between trophic status, sediment redox chemistry and arsenic mobility in a historic tailings repository. The results demonstrate that in eutrophied systems which exhibit greater sediment oxygen demand, the depth of the Fe(III) redoxcline, and hence depth of arsenic release, may lie in close proximity to the sediment-water interface. As a result, arsenic scavenging mechanisms are significantly reduced, resulting in a greater flux of arsenic to the water column. Such considerations have important implications for the management of pit lakes, tailings ponds and contaminated lakes which may consider: 1) the discharge of sewage to the water body during operations; and/or 2) post-closure fertilization as a remediation strategy.

Jan 1, 2002

By L. S. Leal Filho, L. A. F. Barros, S. M. Assis

Zeta potential determinations and microflotation tests (with starch, sodium oleate and flotigan EDA-B) versus pH, pCa and pMg were performed with apatite and typical silicate minerals that occur in Brazilian phosphate ores: schorlomite, diopside, quartz and micas. Unlike quartz and micas, schorlomite and diopside were depressed by cornstarch during anionic flotation with sodium oleate (pH 1 9). The selectivity of the separation apatite/quartz and apatite/micas by flotation with sodium oleate was adversely affected by the presence of calcium (pCa) and magnesium (pMg) in flotation pulp. Solubility/cation exchange capacity of micas is an important source of dissolved calcium and magnesium in the system.

Jan 1, 2002

By Grégory Miette

The paper deals with a process that allows the recycling in a cupola of EAF dusts with 18 % Zn. It produces dusts with zinc grade higher than 50 - 55 % and commercial cast iron with less than 200 ppm Zn, 50 ppm Pb, 0.15 % S. The paper focuses mainly on lab tests made with the aim to develop an effective formulation of self reducing - melting pellets. With such a formulation, agglomerates develop a breaking load higher than 125 - 150 kg without any thermal treatment. Zinc and lead are volatilized in the cupola with yields higher than 95 % at 1200 OC, before any melting. Sulphur is transfemed into gas and slag. All these conditions allow to lower zinc, lead and sulphur grades below the cast iron specifications. Results of first bench scale tests performed at Fonderie Piret to validate the process will be presented.

Jan 1, 2002

The tangible effects of leakage are presented graphically, and a technique for quantifying the leakage characteristics of a ventilation column using the æSolveÆ capabilities of a common spreadsheet is demonstrated. A case study of a working decline in Western Australia is used to demonstrate the potential for more realistic design of development ventilating systems, and for more cost effective management of the condition of the duct.

Jan 1, 2002

By N Kusuma

Recoverable copper and gold estimates for resource models and ore control routing decisions at Batu Hijau were initially based on flotation testwork from several commercial laboratories. Due to the greater number of copper and gold assay grade available, regression relationships were developed between assay grades and flotation recoveries. Other recovery controlling variables such as oxidation and lithology were included to improve the regression models. With additional drilling, more flotation work was carried out and the regression models were revised to include the new flotation data, also alteration classification and in situ pH. The regression models were replaced in favour of spatially derived models for ore control and short range mine planning. To harness local variability in the block model, blast hole flotation testing is carried out in unison with routine grade assaying. Recovery data are processed (kriged) simultaneously with grade assay data prior to ore polygon delineation. Short range mine planning utilises this model in conjunction with a spatial recovery model derived from drill core flotation data. Long range mine planning utilises the æhybridÆ recovery model whereby the globally robust regression recovery models are overprinted by a spatial (kriged) recovery estimate where flotation data density is adequate (Phase II reserve).

Jan 1, 2002

By Y Gu, W McCallum

Mathematically sophisticated methods are now in common use for metal balancing of complex separation flow sheets at many concentrators. These balances usually entail minimisation of the sum of weighted squares of data adjustments subject to flow sheet constraints. The adjusted data provides numerical consistency across the complete flow sheet to facilitate performance calculations. A mine with multiple ore sources can be considered as a flow sheet with the end node comprising the concentrator and its products concentrate(s) and tailings. If the mass transfer and grade estimates for each ore source are sufficiently reliable, a similar metal balancing approach can be used for combined mine and concentrator data. Comparison of balanced and measured assays and mass movements provides useful guidance to security of marginal grade ore and possible dilution problems. This paper includes a summary of results from a case study based on a mine with multiple ore sources.

Jan 1, 2002

By E N. Sajin

The final arsenic bearing waste products at the majority of metallurgical and chemical enterprises are cakes in which arsenic is present in the form of calcium arsenate. Burial of cakes demands construction of special burial sites and does not guarantee reliable protection from arsenic penetration into the ground and surface waters. Under laboratory conditions we developed technology for processing calcium arsenate cakes with obtaining low toxic products suitable for long-term storage, meeting environmental requirements. The investigations have shown that thermal processing of briquetted mixtures of cakes containing 15 - 20 per cent weight of pyrite under the temperature of 873 - 923¦K during 45 - 60 minutes gives briquettes sufficiently hard for transportation and long-term storage. Arsenic, under high sulphidisation temperature is bonded into low solubility non-volatile iron sulphide bearing compounds having chemical properties similar to the natural arsenic compounds. Solubility of the obtained products in neutral, acid and alkaline media was investigated during long period of time (three to 12 months). It was determined that arsenic content in the solutions did not exceed the norms for cultural and welfare basins and fish-ponds.

Jan 1, 2002

By H. Sis, D. Dahlin, S. Chander, C. Summers

Bench-scale selective-flocculation tests were conducted on samples of Florida and Western phosphate process tailings. Physical, mineralogical, and surface characteristics were determined for both types of samples. The flocculation tests investigated dispersant and flocculant types and doses, pH, and slurry percent solids, while other parameters were held constant. Where selectivity was achieved, phosphate minerals remained dispersed, whereas silicate minerals flocculated and settled. In single-stage tests, flocculants having low to medium anionic character effectively upgraded products at moderately elevated pH. Multiple-stage tests, and tests in which flocculants of lower molecular weight were used as site-blockers, gave improved results.

Jan 1, 2002

In May 2000, Kanowna Belle Gold Mines (KBGM) carried out a detailed Truck versus Shaft Haulage Study. The study showed that whilst the shaft option had many operating cost benefits the capital costs were too high, therefore the truck option was selected. In May 2001, the concept of achieving æshaft typeÆ benefits without the capital costs was floated. This is achieved by separating the hoisting of ore from other mining activities. The general concept is that material from underground is transported to a central location and then transported to the surface by a special truck fleet, thus removing the dependency between trucks and loaders, providing the mine with surge capacity and decreasing operating costs. At KBGM these advantages have been gained by installing an ore pass system with a plate feeder at its base that directly loads trucks. This provides the mine with a haulage system with enough surge capacity to remove the interdependency between trucks and loaders. The plate feeder is situated just off the decline which creates the opportunity to use larger more reliable, lower cost trucks. A number of truck types were considered for the truck loop including Elphinstone AD55Æs which are the truck type being used on site prior to the truck loop, CAT 775EÆs and power trailer road trains. This paper covers the philosophy behind the truck loop, the truck selection process, project installation and commissioning, people issues and the benefits expected by the operation. As of May 2002, the project is nearing completion, with decline haulage expected to commence in July 2002.

Jan 1, 2002

By M. J. Gula, S. S. Xue, E. P. Horwitz, J. T. Harvey

A study was conducted to control iron in copper electrolyte streams using Eichrom Industries' new monophosphonic/sulphonic acid resin. The resin strongly and selectively extracts ferric ion over copper and cobalt from highly acidic copper electrolytes. The resin has a loading capacity of 27-g/L iron and can be readily regenerated. In addition, the new resin can easily be synthesized using commercially available starting materials. This paper presents the experimental results for iron control in copper electrolyte streams using the new resin and discusses its potential applications to other hydrometallurgical streams.

Jan 1, 2002

By L. G. Austin

The data of Dunn and Martin (1978) is reanalyzed using a rigorous application of Hertzian theory to the impact process. The Young's modulus of steel required to fit their data to the theory is a factor of about 10 3, too low compared to the values quoted for steels. Thus, doubt is thrown on the validity of their experimental technique, and it is possible that their values for maximum impact force and stress are far too low.

Jan 1, 2002