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Ng K.W.,CANMET Energy | Giroux L.,CANMET Energy | MacPhee T.,CANMET Energy | Todoschuk T.,ArcelorMittal | Kolijn C.,Teck Coal Ltd
AISTech - Iron and Steel Technology Conference Proceedings | Year: 2013

Coke bed permeability significantly affects the blast furnace performance and needs to be carefully controlled. Size and shape characteristic of coke is the determining factor that governs the permeability of coke bed. Conventional screen analysis was found incapable of providing sufficient information for bed permeability estimation and is also time consuming. A new approach employing image analysis for characterisation of coke size and shape was developed. This method provides sufficient information to allow bed pressure drop estimation using Ergun's equation. Bed permeability calculated from coke size and shape characterization was validated with experimental measurement and close agreement was observed.

MacPhee T.,CANMET Energy | Giroux L.,CANMET Energy | Ng K.W.,CANMET Energy | Todoschuk T.,ArcelorMittal | And 2 more authors.
Fuel | Year: 2013

Coke Strength after Reaction (CSR) and the concomitant Coke Reactivity Index (CRI) are useful parameters for assessing the behavior of coke in blast furnace. To measure CSR and CRI of the resultant coke from a particular metallurgical coal or blend, a pilot scale oven test for producing appropriate industrial grade coke for measurements is unavoidable. If the quantity of coal sample available is not sufficient for pilot scale oven test, CSR measurement of the resultant coke is normally not possible. CanmetENERGY has developed a procedure for producing coke to allow CSR measurement involving relatively small amounts of coal sample (~15 kg). The procedure involves producing semi-coke using the Sole Heated Oven in accordance with ASTM standard D2014-97 (2004). In the Sole Heated Oven test the coal sample is heated only from the bottom (the sole) up to 950 °C with the top of the oven charge rising to 500 °C over a period of 6-7 h. The resulting semi-coke is quenched (either wet or dry) and subsequently reheated to 1100 °C under nitrogen for 1 h. CSR and CRI are measured using the coke produced using this procedure. To demonstrate the validity of CSR and CRI measured using this approach, identical coal blends were carbonized concurrently using the CanmetENERGY pilot scale moveable wall oven (460 mm wide, 350 kg capacity) and the procedures mentioned above. CSR and CRI of the cokes produced by these two approaches were compared. Statistical analysis and coke textual analysis were performed to demonstrate the relevance of this novel approach on CSR determination. Crown Copyright © 2012 Published by Elsevier Ltd. All rights reserved.

Orr P.L.,Minnow Environmental | Wiramanaden C.I.E.,Minnow Environmental | Paine M.D.,Paine | Franklin W.,Teck Coal Ltd | Fraser C.,Teck Coal Ltd
Environmental Toxicology and Chemistry | Year: 2012

Previous studies conducted in the Elk River watershed showed that selenium concentrations are higher in aquatic biota in lentic compared to lotic habitats of the system having similar water selenium concentrations. Studies have also shown that water selenium concentrations have increased over time (~10% per year) and recent annual average concentrations have ranged up to 0.044mg/L in areas downstream from mine discharges. For the present study, trophic transfer of selenium was characterized in lotic versus lentic habitats using concentrations measured in field-collected samples and assuming a three-step food chain of water to the base of the food web (biofilm), to benthic invertebrates, and then to westslope cutthroat trout (WCT) ovaries. Food chain models were developed for each habitat type (lotic and lentic) by combining linear regression equations for the three transfer relationships, allowing for prediction of fish ovary concentrations from water concentrations. Greater accumulation of selenium in lentic areas was mostly attributable to greater uptake at the base of the food chain compared to lotic areas. Enrichment/trophic transfer factors for selenium at all levels of the lotic and lentic food chains decreased and then became near constant as exposure concentrations increased. The lotic model predicted little increase in WCT ovary selenium concentrations over an eightfold increase in water concentrations (~0.005-0.040mg/L), accounting for the lack of observed increase in within-area fish tissue concentrations over time despite increasing trends in water concentrations. © 2011 SETAC.

Holuszko M.E.,University of British Columbia | Leeder W.R.,Teck Coal Ltd. | Mackay M.,Trillium Geoscience Ltd. | Giroux L.,CANMET Energy | And 3 more authors.
Fuel Processing Technology | Year: 2016

The effect of organic liquids (white spirit, perchloroethylene and methylene bromide) typically used in float/sink gravity separations (specific gravity 1.4-1.8) on the fundamental properties of a higher-inert Western Canadian metallurgical coal of mvb rank (Romax 1.22) and its resultant coking ability were examined. Over a 6-month period, untreated (control) and treated coal were characterized using a wide range of analyses including elemental chemistry, FTIR spectroscopy, alkali extraction via light transmittance test and thermal rheology, specifically fluidity, Dilatation, FSI and Caking Index G. Exposure to organic liquids was found to have a minor effect on coal chemistry (Ultimate) and oxidation level (Alkali Extraction via Light Transmission Test and FTIR-Spectroscopy). Trends of H/C, O/C, Light Transmittance and FTIR absorbance spectra versus storage time, following initial 1h exposure to the organic liquids of varying specific gravities, revealed only minor changes, within the scatter/accuracy of the measurements. However, several coal plastic properties were decreased significantly including Gieseler Maximum Fluidity, Dilatation and G Caking Index. Of these, most affected was Maximum Fluidity which underwent an immediate and dramatic decrease of over 80% following organic liquids treatment. Other rheology indicators including FSI and Sapozhnikov were significantly less sensitive in detecting initial stages of degradation in plastic properties. The coking ability of both the untreated and treated coal in perchloroethylene (PCE) organic liquid, s.g. 1.6, after storage for 1 and 6months was assessed through carbonization trials in both a small-scale sole-heated oven (12.5kg capacity) and in a pilot-scale movable wall oven (350kg capacity) at CanmetENERGY Carbonization facility, Ottawa, Canada. The treated samples had appreciably poorer quality ambient (ASTM, IRSID, JIS tumbler tests) and hot (CSR, CRI) coke strength and modified coke structure. Coke ASTM strength for untreated and treated coal at time 1month was respectively decreased from 62 down to 57 for Stability and from 72 to 67 for Hardness. Similarly, Coke CSR and CRI for untreated and treated coal at time 1month was respectively decreased from 74 down to 58 and increased from 21 to 29. The treated sample resulted in a lower coke yield, 71%, in comparison with 78% for the untreated sample, produced coke of smaller mean size, 46mm, than the untreated sample, 53mm, and generated an appreciably higher fraction of fines (-12.5mm), 21%, than untreated sample, 4%. The coke textures from the untreated coal consist of higher carbon forms, mosaic and flow in medium size, compared to those from s.g. 1.6 treated coal of lower carbon forms, very fine and fine mosaic, which renders the coke more reactive to CO2 gasification during CSR test. The higher effective coking rank, 1.2, and Coke Mosaic Size Index, 2.4, of untreated sample relative to that of treated one, 1.1 and 2.2, respectively, supports the better coke quality of the untreated sample. Extension of storage time to 6months resulted in negligible changes in coke quality showing that the greatest changes occurred within the first month following exposure to organic liquids. Comparison of 1month untreated and PCE treated mid coking rank Western Canadian (Romax 1.22) and Australian (Romax 1.17) coals show both to undergo comparable decrease in fluidity (50-60%) post treatment with PCE although only the Western Canadian coal leads to lower dilatation. Coke yield is also decreased for the Western Canadian coal and essentially maintained for the Australian coal. Both CSR and CRI are affected negatively and more so for the Western Canadian coal, 16 point drop in CSR and 8 point increase in CRI, relative to the Australian coal, 3 point drop in CSR and 4 point increase in CRI. © 2016.

Bauer F.,Teck Coal Ltd.
Journal of Explosives Engineering | Year: 2014

The Fording River mine in British Columbia produces hard coking coal in an open pit operation. Coal seams are exposed by blasting overburden and digging blasted muck with rope shovels. The drilling and blasting process presents a considerable cost factor to the operation. Reducing the amount of explosives needed therefore contributes considerably to costs saving initiatives. However, reducing the powder factor only makes sense if the subsequent loading processes by the shovels are not compromised in terms of productivity. In order to achieve a reduction in powder factor without compromising shovel productivity, two key indicators of fragmentation and shovel dig rate were measured as powder factor was reduced. A fragmentation baseline was set as the starting point of the study, and then only very slowly was the explosive column collar lowered and the blast hole burden and spacing increased. The key indicator chosen to measure the impact to the shovel productivity was single-pass load time. Specifically, the single-pass load time measures how long it takes a shovel to dig into blasted muck and unload the bucket into a haul truck. An increase in the single-pass load time due to a much coarser fragmentation would therefore indicate that more power and time is used to dig the blasted material. The study aims to find the point at which the savings from reduced explosives costs would be less than the increased costs for digging. The study shows how, over a timespan of more than one and a half years, the changes to collar, burden, and spacing have resulted in a considerable powder factor reduction. It can also be seen that fragmentation sizes slowly increase, while dig rates stay relatively unchanged. This can be interpreted as a sign that the limits of the powder factor reduction strategy have not been reached yet, and efforts will be made to further reduce the powder factor. For such a study to be successful it is crucial that changes are not implemented too quickly and results of any changes are monitored closely so that any problems can be dealt with immediately with little impact to production.

Schwarz C.J.,Simon Fraser University | Cope S.,Westslope Fisheries Ltd. | Fratton G.,Teck Coal Ltd
Ecology and Evolution | Year: 2013

Movement models require individually identifiable marks to estimate the movement rates among strata. But they are relatively expensive to apply and monitor. Batch marks can be readily applied, but individual animal movements cannot be identified. We describe a method to estimate population size in a stratified population when movement takes place among strata and animals are marked with a combination of batch and individually identifiable tags. A hierarchical model with Bayesian inference is developed that pools information across segments on the detection efficiency based on radio-tagged fish and also uses the movement of the radio-tagged fish to impute the movement of the batch-marked fish to provide estimates of the population size on a segment and river level. The batch marks provide important information to help estimate the movement rates, but contribute little to the overall estimate of the population size. In this case, the approximate equal catchability among strata in either sample obviates the need for stratification. © 2013 The Authors.

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