Ore Transportation Research Articles

Hydrotransport system simulation modeling for Syncrude's North Mine

ABSTRACT Syncrude Canada Ltd. presently mines 140 million tonnes per year of oil sand, 60 million of which comes from two mining areas nearing completion. These are the northeast and southeast which are currently mined using two 90 cubic yard draglines, two bucketwheel reclaimers and two feeder breakers utilizing 12 kilometres of 72 inch conveyors, feeding a common stockpile that supplies the extraction plant. With the completion of mineable reserves in the southeast in 1998, and the northeast in 1999, a new mine area will be opened to the northwest utilizing hydrotransport technology. This technology developed and field tested by Syncrude, consists of high density slurry preparation vessels and pipelines receiving feed from crushers that are fed by a shovel/truck fleet. When compared to a conveyor system which would eventually have required 57 kilometres and up to 34 flights of 72 inch conveyor, with attendant low utilization and high operating cost, hydrotransport has the potential to reduce transportation costs and at the same time enable digestion of the oil sand in the pipeline to the Extraction plant. A discrete event simulation program was developed and used to provide production volumes and statistics to assist in the selection and sizing of key elements of the integrated operation of the mining and “Hydrotransport” equipment, from the mine face, to the Extraction plant. This program can been used to establish shovel and truck fleet sizes, examine queue times at shovels and crushers, select crusher rate, determine hopper and intermediate bin sizes, and to enable system designers to focus on bottlenecks. Future applications of this toot include the modeling of the shovel/truck overburden fleet and integration of the overburden and ore transportation operations.

Simulation model of ore transport at the Henderson mine

Computer simulation of mining processes is a cost-effective tool for evaluating what-if scenarios in mine development and ore production. In this paper, data from the 8100-ft level of AMAX Corporation's Henderson molybdenum mine near Empire, Colorado is used to simulate the ore-transport process. The purpose of the simulation was to demonstrate to mine management how simulation could be used to assist in optimizing ore transport using existing trains, trucks, and ore passes.

Using artificial neural networks for the control of grinding circuits

Artificial Neural Networks (ANN) is a technique developed by the Artificial Intelligence community which is able to approximate relationships between multiple inputs and outputs of a system. The network is trained to develop these relationships using appropriate data. ANNs have received considerable attention with respect to their use in control systems. The use of ANNs in the control of an autogenous milling circuit is investigated. A dynamic simulation of the circuit behaviour is used as a basis for the investigation. A detailed dynamic mill model has been developed which combines much of the work reported in the literature into a comprehensive model which simulates size reduction, mass transport of ore and pulp in the mill, temperature effects and mill power draw.

D- 18O enriched waters of the Coast Range Mountains, northern California: Connate and ore-forming fluids

D and 18O enriched waters of several weight percent salinity issue from hot and cold springs in Franciscan Complex and Great Valley Sequence rocks in the northern Coast Range Mountains of California. Although these waters have been described separately in the past and called “metamorphic,” “connate,” and “serpentinizing fluids,” this study shows that the hot and cold springs are all fed by one source of water—trapped Cretaceous seawater modified by a variety of reactions. The district is an example of the complexities of subsurface waters and their importance for our understanding of metamorphic fluid sources, oil-field waters, and ore transport problems. The subsurface waters have a range of δ 34S values, including some near marine sulfate values (+20%.), and δ 13C near marine calcite values (0%.). Strontium isotopic signatures in the spring waters are derived from the Great Valley Sequence ( 87Sr 86Sr values near 0.705). The most saline spring pool is lined with serpentine phases found together as a fine white precipitate and has a pH of 11. One portion of the subsurface water is heated and reduced; it transports Au, Ag, Sb, As, and Hg to the surface (gold grades of the hot spring precipitates range from less than 1 ppm to over 10 ppm). These heated waters are chemically and isotopically similar to the fluids which formed Au mineralization at the nearby McLaughlin gold mine. The hot springs precipitate pyrite and native sulfur and are supersaturated with respect to calcite. Other springs are less saline and are oxidized, cooler, and diluted versions of the hot spring fluid. They do not carry ore metals but they are supersaturated with respect to silica and calcite. 3He 4He ratios of the springs gases are all above atmospheric values and indicate a possible magmatic component, consistent with the presence of Quaternary Clear Lake Volcanics. 129I data yield a minimum age of 60–80 Ma for the source of the iodide in the waters, consistent with the connate nature of the source fluid (FEHN et al., 1992).

Characterization of long-lived radioactive dust in uranium mill operations.

The characteristics of long-lived radioactive dust clouds generated in several mechanical and physiochemical operations in a uranium mill have been investigated. The study consisted of the determination of dust size distribution and of the size distribution of radionuclides associated with particulate matter in the size range less than 0.1 to 26 microns. Experiments were conducted by using two different types of cascade impactors operating at different sampling flow rates. Radionuclide identification was done by using alpha-spectrometry. Long- and short-lived radionuclides were identified in dust samples. The characteristics of the dust clouds depended on the mill operation, such as crushing (vibrating grizzly, jaw crusher, cone crusher); screening; ore transportation; grinding; acid leaching; counter-current decantation; yellow cake precipitation and drying; and yellow cake packaging. In addition, other dust and radioactivity measurements have been carried out.

Geotechnical centrifuge modelling at the University of Western Australia : Fahey, M; Finnie, I; Hensley, P J; Jewell, R A; Randolph, M F; Stewart, D P; Stone K J L; Toh, S H; Windsor, C S Aust GeomechN19, Dec 1990, P33–49

This paper has described the new geotechnical centrifuge facility at The University of Western Australia (UWA), and summarised the various research projects that are currently being undertaken using the centrifuge. In addition to the projects already described, there are many other areas where centrifuge modelling may prove useful. The centrifuge, by its nature, is ideal for any problems where self-weight loading is important. Such problems may involve static loading, as in retaining walls, reinforced soil, soil nailing, and the stability of slopes and excavations, or may involve dynamic loading where inertial and flow effects become important. Centrifuge modelling has played a key role in research on earthquakes, and events such as blast loading, where inertial effects are critical. There is also a useful role to play for problems involving flow of granular materials, for example in the mining industry (transport, stockpiling and retrieval of ore and waste material) or in silo design. The range of geotechnical problems where centrifuge modelling may prove useful is enormous, and it is likely that other geotechnical centrifuges will be established in Australia over the next few years. In the meantime, the centrifuge at UWA is seen as a national facility, and it is hoped that researchers and design engineers throughout Australia will make use of the facility. (Author/TRRL)

Reduction of Airborne Radioactive Dust by Means of a Charged Water Spray

An electrostatic precipitator based on charged water spray technology has been used in an underground uranium mine to control long-lived radioactive dust and short-lived aerosol concentration in a mine gallery where dust from a rock breaking/ ore transportation operation was discharged. Two main sampling stations were established: one upstream of the dust precipitator and one downstream. In addition, dust samplers were placed at different locations between the dust discharge and the end of the mine gallery. Long-lived radioactive dust was measured using cascade impactors and nylon cyclone dust samplers, and measurement of the radioactivity on the samples was carried out by conventional methods. Radon and thoron progeny were estimated using standard techniques. Experiments were conducted under a variety of airflow conditions. A maximum radioactive dust reduction of about 40% (∼20% caused by gravitational settling) at a ventilation rate of 0.61 m3/sec was obtained as a result of the combined action of water scrubbing and electrostatic precipitation by the charged water spray electrostatic precipitator. This represents the optimum efficiency attained within the range of ventilation rates investigated. The dust reduction efficiency of the charged water spray decreased with increasing ventilation rate, ie., decreasing air residence time, and hence, reduced dust cloud/charged water droplets mixing time.

Reduction of airborne radioactive dust by means of a charged water spray.

An electrostatic precipitator based on charged water spray technology has been used in an underground uranium mine to control long-lived radioactive dust and short-lived aerosol concentration in a mine gallery where dust from a rock breaking/ore transportation operation was discharged. Two main sampling stations were established: one upstream of the dust precipitator and one downstream. In addition, dust samplers were placed at different locations between the dust discharge and the end of the mine gallery. Long-lived radioactive dust was measured using cascade impactors and nylon cyclone dust samplers, and measurement of the radioactivity on the samples was carried out by conventional methods. Radon and thoron progeny were estimated using standard techniques. Experiments were conducted under a variety of airflow conditions. A maximum radioactive dust reduction of about 40% (approximately 20% caused by gravitational settling) at a ventilation rate of 0.61 m3/sec was obtained as a result of the combined action of water scrubbing and electrostatic precipitation by the charged water spray electrostatic precipitator. This represents the optimum efficiency attained within the range of ventilation rates investigated. The dust reduction efficiency of the charged water spray decreased with increasing ventilation rate, i.e., decreasing air residence time, and hence, reduced dust cloud/charged water droplets mixing time.

Solubility of the assemblage pyrite-pyrrhotite-magnetite-sphalerite-galena-gold-stibnite-bismuthinite-argen- tite-molybdenite in H 2 O-NaCl-CO 2 solutions from 200 degrees to 350 degrees C degrees

The simultaneous solubilities of the minerals pyrite, pyrrhotite, magnetite, sphalerite, galena, gold, stibnite, bismuthinite, argentite, and molybdenite have been measured in 0 to 5 m NaCl solutions from 200 degrees to 350 degrees C at CO 2 partial pressures from 0.69 to 172 bars with oxygen and sulfur fugacities controlled by the pyrite-pyrrhotite-magnetite buffer. The relative solubilities follow the sequence Sb > Fe > Zn > Pb > Ag, Mo > Au, Bi in chloride-free solutions, and Fe > Sb > Zn > Pb > Au > Ag,Mo,Bi in concentrated chloride solutions. Gold solubilities as high as 5 ppm were measured in 5 m NaCl solutions. The aqueous species responsible for ore transport have been proposed based on the dependence of the solubilities on NaCl concentration and previous work on individual metal systems described in the literature. Although iron, zinc, lead, gold, and silver form chloride or hydroxy-chlo-ride complexes in 0.5 to 5.0 m NaCl solutions under these conditions, molybdenite solubility is independent of chloride concentration and stibnite solubility shows an inverse relationship to chloride content. Molybdenum is probably transported as an oxyacid and antimony as a neutral hydroxide complex. Bismuth may be chloride complexed, but the solubility of bismuthinite is so low and the results so scattered that the hydrothermal speciation of this metal remains in doubt. In the chloride-free solutions, iron is present mainly as the simple ferrous ion; zinc, antimony, and bismuth as hydroxy complexes; lead as a carbonate complex; molybdenum as molybdic acid; and gold and silver as bisulfide complexes. Mixed metal complexes appear to be unimportant under the experimental conditions. The speciation results are consistent with the Pearson hard-soft rule.

Rare-earth element distributions in uraninites: Implications for ore genesis

Analysis of the rare-earth element (REE) distributions in uraninites from a variety of hydrothermal mineral deposits indicates that wide variations are to be anticipated. Although crystal structure must exert a fundamental influence upon REE substitution in uraninite, the present study suggests that other factors, in particular hydrothermal fluid chemistry, may be of equal importance. Total REE (ΣREE) contents range from > 15,000 ppm in uraninites from ultrametamorphic deposits to < 2000 ppm in uraninites (the variety pitchblende) from unconformity-type U deposits. Other characteristics of the REE distributions such as the presence of Eu anomalies and the existence of marked within-group fractionations are equally varied ( Eu Eu ∗ = < 0.01 – 1.15 ; LREE HREE = 0.08 – 1.10 ); they are interpreted to result from variations in the oxygen fugacity and the nature of the anionic complexes in the hydrothermal fluids responsible for ore transport. Additionally in uraniferous quartz pebble conglomerates the REE patterns of the detrital uraninites provide direct evidence regarding the provenance of these sedimentary U ores.

SNOW AS A RESOURCE AND HAZARD IN EARLY-TWENTIETH-CENTURY MINING, SELKIRK MOUNTAINS, BRITISH COLUMBIA

Snow as both a resource and a hazard is discussed in the context of early-twentieth-century mining in the southern Selkirk Mountains of British Columbia. This case study focuses on the Carpenter Creek region, a productive silver mining area during the period 1892–1930. Historical data sources including newspapers, government reports, anecdotal literature, and photographs, have been employed. As a resource, snow usually provided a plentiful water-supply for domestic, industrial, and power-generation purposes and served as the basis of ore transport from most minesites by the process of rawhiding. As a hazard, snow disrupted trail and rail transport and was the basis of an enduring avalanche risk that often resulted in deaths, injuries, and structural damage. Mining and related activities destroyed much of the natural forest cover, which led to an increased extent of avalanches. A variety of technological and behavioural adjustments were made to mitigate the hazards posed by snow. Other hazards such as forest fires and flooding, coupled with socioeconomic conditions, such as silver prices, labour shortages, and strikes, adversely affected the local economy throughout the period of study. However, the ultimate demise of the economy resulted from the collapse of world silver prices in 1929.

A Microprocessor Based Information and Control System for Essential Services on a South African Gold Mine

The application of cheap robust microprocessor based units to achieve monitoring and control in an underground raining environment is described. The functional layout of the programmable controller and the methods of Multiplexing and processing Information from local and remote sources are examined as are features for refrigeration plant control. High noise immunity communication to a remote micro computer uses existing telephone lines and enables display and print of essential data. The development of this system then leads to applications In monitoring compressed air, ore transport and underground fires In conclusion, the problems of data presentation to different levels of management and the future philosophy of a central multi-reporting system are discussed

Fragmentation Control and Underground Automation

Compared with modern longwall coal mining systems, automation has not been developed very far in the underground metal mining industry. One of the main reasons for this is that present hard rock raining systems do not produce ore with a controlled degree of fragmentation. The often poor fragmentation from the stopes causes large extra costs and precludes a continuous flow of material which lends itself to automation The paper investigates the possibility of adapting coal mining technology for automatic loading and transport of stope ore by conveyor belt to a shaft dump pocket. With this concept, it will be necessary to control the maximum fragment size by careful blasting design. The degree of fragmentation will have to be finer than is common to-day. The study shows that the belt conveyor mining concept with controlled fragmentation may be economically competitive with conventional cyclic loading and transport, even for an annual production as low as 0.5 mill, tonnes. Fragmentation design and cost calculations have been based on a combination of the Kuznetsov relationship between blasting parameters and mean fragment size, and the Rosin-Rammler formula for fragment size distribution

柵原鉱山

Yanahara Mine is located in Kume-gun, western part of Okayama Prefecture, and produces iron sulfide ore. Total annual production is 132, 000 tons of crude ore. The number of mine personnel is 92 in all, and separated to two divisions; the mining division and the administrative service division. The mining division consists of four sections; mining, maintenance, concentra-tion and water treatment. The operations are proceeded in day shifts.The orebodies are bedded deposits, and their main iron mineral is a high grade pyrite. They lay in volcaniclastic rocks and slate of permian. The hanging wall is slate and the foot wall is diabase and quartz-diorite. The orebodies extend in an area of approximately 2, 000m×400m with an average thickness of 60 meters.Yanahara Mine has two main shafts. One is used for mine service, another is used for ore transportation. Level drifts are generally located at 15 meter intervals from L+6 to L-60, while several sublevels are prepared among them. The orebody being mined is divided into the northern block and the southern block. A central pillar runs between them from east to west. The mining method applied is a sublevel stoping, and the mined space is filled with waste rocks. The primary stoping has been finished, and regular band pillars are currently being mined.All the ore mined are crushed by a jaw crusher located at L-32, and wound up through the shaft to the gravity concentration plant. To meet the market's needs, the concentrates are classified to several brands according to their size and grade. The main usages of products are high grade iron oxide, sulfuric acid and heavy concrete.

The role of fluorine in submarine exhalative systems with special reference to Broken Hill, Australia

Fluorine-bearing minerals are uncommon in submarine exhalative ores, exhalites and associated alteration zones, probably because of the low solubility of CaF2. The Broken Hill (Australia) deposit contains fluorapatite and fluorite with one lens containing 1.35% F and greater than 3 volume % F-bearing minerals. The calcite-fluorite-fluorapatite assemblage at Broken Hill indicates that ore deposition was probably from hypersaline fluorine-bearing fluids which decreased in pH by base leaching reactions which released Ca2+ and mixing with seawater promoting the rapid and simultaneous precipitation of calcite, fluorite and fluorapatite as a result of temperature and salinity decrease and pH and [Ca2+] increase. The abundance of fluorine minerals in the Broken Hill ore and the association of F and B minerals with stratigraphically equivalent W- and Sn-bearing exhalites suggest that F complexes are important for ore transport in some exhalative systems. The Fe/Mn ratio decreases and the F/Cl ratio increases in fluorapatite in exhalites with increasing proximity to the Broken Hill deposit.

50 kV Locomotives for a Mineral Railway

An 846 km line for the transport of iron ore was electrified in 1978-9 at 50 kV a.c. The 3780 kW Co-Co locomotives used to haul trains of 20,000 tonne are described.

Ore transport and deposition in the Red Sea geothermal system: a geochemical model

Thermodynamic calculation of distribution of dissolved aqueous species in the Red Sea geothermal brine provides a model of ore transport and deposition in good agreement with observed accumulations of base metal sulfides, anhydrite, and barite. The Red Sea brine is recirculated seawater that acquires high salinity by low-temperature interaction with Miocene evaporites and is subsequently heated to temperatures in excess of 200°C by interaction with recent rift zone intrusive rocks. At temperatures up to 250°C, NaSO − 4 and MgSO 0 4 are the dominant sulfur-bearing species. H 2S forms by inorganic sulfate reduction at the higher temperatures but is maintained at a uniform concentration of about 2 ppm by the strength of the sulfate complexes. Chloride complexes solubilize metals at the higher temperatures, and thus sulfide and metals are carried together into the Atlantis II Deep. Below 150°C, the brine becomes supersaturated with respect to chalcopyrite, sphalerite, galena, and iron monosulfide due to chloride-complex dissociation. Sulfide precipitation rates, based on the rate of brine influx, are in good agreement with measured sedimentation rates. Anhydrite precipitates as crystalline fissure infillings from high-temperature inflowing brine. Barite forms from partial oxidation of sulfides at the interface between the lower hot brine and the transitional brine layer.

Identification of the origin of oreforming solutions by the use of stable isotopes

Synopsis The four major different types of water — magmatic, metamorphic, sea water and/or connate, and meteoric water — have characteristic hydrogen (D/H) and oxygen ( 18 O/ 16 O) isotope ratios. Applied to the analysis of isotopic data on hydrothermal minerals, fluid inclusions and waters from active geothermal systems, these ratios indicate that waters of several origins are involved with ore deposition in the volcanic and epizonal intrusive environment. Water of a single origin dominates main-stage mineralization in some deposits: magmatic — Casapalca, Peru (Ag-Pb-Zn-Cu); meteoric — Butte, Montana (Cu-Zn-Mn), epithermal deposits, e.g. Goldfield, Tonopah, Nevada (Ag-Au), Pachuca, Mexico (Ag-Au), San Juan Mountains District, Colorado (Ag-Au-Pb-Zn); sea water — Troodos, Cyprus (Fe-Cu), Kuroko, Japan (Fe-Cu-Pb-Zn). Solutions of more than one origin are important in certain deposits (magmatic and meteoric — porphyry copper and molybdenum deposits) and are present in many. In the porphyry Cu-Mo deposits the initial major ore transportation and alteration processes (K-feldspar-biotite alteration) are magmatic-hydrothermal events that occur at 750–500°C. These fluids are typically highly saline Na-K-Ca-Cl-rich brines (more than 15 wt % equivalent NaCl). The convecting meteoric-hydrothermal system that develops in the surrounding country rocks with relatively low integrated water/rock ratios (less than 0.5 atom % oxygen) subsequently collapses in on a waning magmatic-hydrothermal system at about 350–200°C. These fluids generally have moderate to low salinities (less than 15 wt % equivalent NaCl). Differences among these deposits are probably in part related to variations in the relative importance of the meteoric-hydrothermal versus the magmatic-hydrothermal events. The sulphur comes from the intrusion and possibly also from the country rocks. Deposits in which meteoric or sea water is the dominant constituent of the hydrothermal fluids come from epizonal intrusive and sub-oceanic environments where the volcanic country rocks are fractured or well jointed and highly permeable. Integrated water/rock ratios are typically high, with minimum values of 0.5 or higher (atom % oxygen) — the magmatic water contribution is often ‘drowned out’. Salinities are low to very low (less than 10 wt % equivalent NaCl), and temperatures are usually in the range 350–150°C. The intrusion supplies the energy to drive the large-scale convective circulation system. The sulphur comes from the intrusion, the country rocks and/or the sea water. Argillic alteration, which occurs to depths of several hundred metres, generated during supergene weathering in many of these deposits is isotopically distinguishable from hydrothermal clays.

Roadside lead contamination in the Missouri lead belt.

The lead content of soils and vegetation along highways used for truck transport of lead concentrate (essentially lead sulfide) from mines and mills to smelters, was compared with that of control routes with comparable amounts of traffic but no ore transport. Greatly elevated levels of lead were present in soils and vegetation along rights-of-way of ore truck routes. Contamination was limited for the most part to 100 yards or less. This dispersal of lead into the environment could be prevented largely by use of tight covers on the ore vats of the trucks. This is a case of needless contamination of our environment with a toxic substance that can have serious health implications for man and other animal life.

Determination of an Optimal Location for an Iron and Steel Plant Based on Iron Ore of the Kursk Magnetic Anomaly

AbstractA locational study of the Iron-Steel Design Institute is criticized on the ground that it selected potential plant sites intuitively and then examined them in terms of proximity to iron ore, water availability and minimal transport requirements. An alternative methodology is proposed. The general region for the new plant is first established on the bases of the interregional balance of iron and steel products. The Central European region is found to have a deficit in the entire product range. A more specific location is then derived by calculating potential transport costs with respect to both markets and sources of raw materials (iron ore, coke). The Rzhev area of Kalinin Oblast is found to be optimal in terms of transport costs alone. But when water and, particularly, labor resources are considered, preference shifts in favor of a plant location in the Gor'kiy-Kostroma area.