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Heat Study and Modelling of Future Climatic Conditions at Coleman/McCreedy East Mine – Vale Inco

Heat Study and Modelling of Future Climatic Conditions at Coleman/McCreedy East Mine – Vale Inco. Charles Kocsis & Stephen Hardcastle CANMET-MMSL, Sudbury, Canada Brian Keen Vale Inco, Coleman/McCreedy East Mine, Levack, Canada. Objectives.

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Heat Study and Modelling of Future Climatic Conditions at Coleman/McCreedy East Mine – Vale Inco

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  1. Heat Study and Modelling of Future Climatic Conditions at Coleman/McCreedy East Mine – Vale Inco • Charles Kocsis & Stephen Hardcastle • CANMET-MMSL, Sudbury, Canada • Brian Keen • Vale Inco, Coleman/McCreedy East Mine, Levack, Canada

  2. Objectives • Perform climatic survey  quantify changes in TDB, TWB, RH and Barometric Pressure of the intake air from surface to the 4810L, through a Cut &Fill stoping area and to the exhaust system of the 153 Orebody • Evaluate the heat load added to the intake air by auto-compression, strata, fans and mining equipment • Predict the climatic conditions for the deepest operating level (5700L) within the future 170 Orebody • Predict the climatic conditions along this future orebody’s main haulage ramp – an exhaust airway ascending from 5700L to 5100L

  3. Methodology • Perform a climatic survey  collect data  determine the heat load added to the mine environment • Perform mine activity monitoring to differentiate between constant (i.e. strata) and transient (i.e. mining equipment) heat sources • Develop a climatic model of the mine’s intake system and the C&F stopes on the 4810L (153 Orebody)  validate simulation data against field data • Transpose climatic model to the 5700L (future 170 Orebody) with intake airflow, BP and VRT entered for this deeper level  predict climatic conditions on 5700L • Extend climatic model to include the ramp system between 5700L and 5100L  predict climatic conditions

  4. Coleman/McCreedy East Mine • Two Alphair 11200-AMF-6600 (880 RPM) in parallel • Power: 1,118 kW (1500hp) each • Two Joy 72-26-880RPM (Series 2000 )-100hp each

  5. No.1 Intake Shaft Two 1120 kW (1500 hp) Alphair 1120-AMF-6600 (880RPM) in Parallel Arrangement Two Exhaust Fans in Parallel Arrangement

  6. Environmental Data Collection • Eleven ACR data loggers were installed along the intake system (surface-4810L) & across the C&F production area • These pocket units continuously recorded TDB, RH and BP, 24 hrs/day at 1-minute intervals  TWB were calculated using standard equations • An infrared (Raytek MX) was used to measure wall surface temperatures along the access drifts and stope area • Kerstel 4000 Pocket Weather Tracker was used for spot measurements within the C&F production stopes • Environmental data was downloaded to a mobile computer at the end of every production shift

  7. Installation of ACR Units On 4810L (#4 Mining Block)

  8. Mine Activity Tracking on 4810L(#4 Mining Block) • During 14-day survey on day-shifts, drilling, bolting/screening, explosive loading, blasting and mucking were monitored and recorded • Data included type and location of activity, start & finish times, mining equipment used, duration of scheduled (i.e. lunch) & unscheduled (i.e. equipment breakdowns) production delays • The operational status (On/Off) of the auxiliary fan was also recorded • The air volumes at the flexible duct discharge to each individual C&F stope was measured for every production arrangement

  9. Mine Activity Tracking - Example Task Codes: D – Drilling; GS – Ground Support; M – Mucking; L – Explosive Loading Sub-Task Codes: DH – Drill Holes; IRB – Install Rock Bolts; MFB – Mucking from Face to Bay; MOB – Mucking from Bay to Ore pass; LH – Load Holes; WU – Wire Holes; CG – Clear and Guard; OW – Other Work; PREP – Prepare for Ground Support Activities; EI – Equipment inspection

  10. Environmental and ActivityData Analysis • The TDB (0C), RH (%) and BP (kPa) data were compiled into daily electronic spreadsheets • The psychrometric TWB (0C) was calculated for each individual set of measurements • Within the spreadsheets the collected activity information, the status of the auxiliary fans and air volumes were also compiled • Once combined it was possible to identify in temperature and humidity graphs where and when mining activity had an impact on the U/G environment

  11. During activities not requiring diesel/el. Equipment, stope background temp. were 28.50C & 23.50C • During two scheduled production delays with aux. fan Off, TDB decreased from 28.5 to 26.90C & from 30 to 28.40C • During bolting/screening (9:00-10:00) TDB, RH & WB remained fairly constant at 28.00C, 58% & 22.00C • Elevated temp. occurred during concurrent mining activities (15:40–16:20). Most airflow directed to adjacent stope Wet-Bulb, Dry-Bulb and RH in the C&F Production Stopes TDB = 4.50C TDB = 3.50C TDB = 2.90C

  12. Average DB and WB Temperatures at the Monitoring Locations (Surface – 4810L) • Greatest temp. increase occurred between surface – intake to 4810L (TDB=+10.60C, TWB=+6.90C ) mainly due to auto-compression • Booster fan delivering air to the 4810L produced TDB=+1.30C in the intake air • The 150hp aux. fan delivering air to the mining block produced TDB=+2.50C • TDB decreased along the aux. duct (TDB=-0.50C)  some of the fan heat was transferred to the 48” steel duct • Within the stope area, on average TDB decreased by -2.50C. However TWB increased by 0.40C  evaporative cooling in the production area VRT4810L = 26.5 0C

  13. The Monitored EnvironmentalConditions in the Production Area • Environmental monitoring data showed that TDB, TWB, RH changed quickly according to the mining activities • Any elevated TDB and TWB returned to stope background conditions with the completion of the activity • These changes were local as TDB and TWB remained fairly constant at the exhaust of the mining block (TDB=0.40C, TWB=0.90C) • The highest TDB and TWB occurred during concurrent mining activities in adjacent C&F stopes (drilling & mucking) • Working conditions in the production stopes were a function of the air volume delivered to each individual stope

  14. Climatic Modelling - #4 Mining Block (4810L) • The climatic model of the #4 mining block (153 Orebody) developed using ClimsimTM • Model based upon mine layouts and the following rock properties: • VRT @ 1,466.5m (4810L) = 26.50C • Geothermal Step: 63 m/0C • Rock Conductivity 5.6 W/m0C • Diffusivity: 2.5 x 10-6 m2/s • Model developed by combining all airway segments from surface to 4810L and the C&F stopes • Simulations showed some difficulties in replicating TDB/TWB in individual stopes with air volume being continually adjusted • As a result & to allow simulation of concurrent activities in adjacent stopes, a “block” model combining all C&F stopes (2W, 2WB, 3W) was developed VRT was provided by Vale Inco obtained from measurements in boreholes

  15. Example of Ventilation Parameters & Heat Sources used in the 4810L Model • Air volume delivered by the auxiliary fan through the 1.2 m steel duct: Vd = 27.5 m3/s • Combined air volume directed to the production stopes through flexible fabric ducts: Vs = 11.5 m3/s • Depth = 1,466 m; Barometric Pressure: BP = 118 kPa • Mini-Jumbo power characteristics: PElectrical = 37 kW; PDiesel = 34 kW; PCompressor= 2.2 kW • Diesel LHD power characteristics: 2.5 yd3 (86 kW); 6.0 yd3 (200 kW); 8.0 yd3 (250 kW)

  16. Comparing simulation vs. average measured data  only major difference is TDB/TWB at the face Simulations were set to represent concurrent activities in two adjacent stopes Model Simulated TDB and TWB for the Active #4 Mining Block (4810L)

  17. Climatic Modelling – Future 170 Orebody (5700L) • The 4810L (Depth = 1,467m) climatic model was transposed to the 5700L (Depth = 1,738m) of the 170 Orebody • Air volumes through the auxiliary ducting system, equipment & auxiliary fan heat sources were similar as within 4810L • VRT entered according to the deeper 5700L (VRT5700L=30.8 0C) • However, to determine the starting TDB and TWB and barometric pressure of the intake air to the 5700L additional modelling work was required

  18. Determining TDB, TWB and BP Through Climatic Modelling Simulations  TDB = 35.3 0C; TWB = 24.4 0C; BP = 123 kPa

  19. Simulated TDB and TWB for the Future Mining Block on the 5700L • Intake TDB/TWB at the 5700L increased by TDb = 5.00C & TWB = 1.50C due to additional booster fans (4215L) and auto-compression  TDB now exceeds VRT = 30.80C • The highest TDB & TWB in the production area would occur at the combined return from the stopes, namely 33.60C and 25.70C (for concurrent mucking & drilling in adjacent stopes)

  20. Climatic Modelling – Main Haulage Ramp • The 5700L model was extended to include two sections of the main haulage ramp (5700L - 5475L) and (5475L - 5100L) • These two sections were considered worst-case-operational conditions • Example of data used for the 5700L – 5475L ramp section: • Volume of air through this section: 71 m3/s • Intake airflow conditions from previous segment: TDB=32.80C; TWB=25.60C • Equipment: Two 2.5 yd3 LHD (2 x 86.5 kW); One 6yd3 LHD (231 kW); Two diesel trucks (2 x 223.5 kW) • Total diesel power: 851 kW

  21. Climatic Modelling – Main Haulage Ramp • Climatic simulations along the (5700L - 5475L) section of the ramp predicted: TDB = 36.8 0C & TWB = 27.2 0C • TWBwould only exceed the mine’s design criteria (TWB = 25.5 0C) if all mining equipment would operate at the same time for prolonged period of time • Predicted TDB & TWB in the upper section (5475L - 5100L) had lower temperatures due to a higher air volume throughout this section

  22. Climatic Simulation Summary – 170 Orebody and Haulage Ramp • Temperature conditions predicted for the intake air to the 5700L would be: TDB=35.3 0C and TWB=24.4 0C • Changes between surface conditions (18.4 0C/15.7 0C) and 5700L  TDB=+16.9 0C & TWB=+8.7 0C are mainly due to heat generated by auto-compression and main/booster fans • During concurrent activities (11.5 m3/s), the highest temperature conditions would occur at the common return location from the C&F stopes: TDB=33.6 0C & TWB=25.7 0C • Along the return airways the predicted temperatures decrease to TDB=32.8 0C/TWB=25.6 0C • Across the 5700L, heat generated by auto-compression, fans and machinery is rejected into the cooler surrounding rock (VRT=30.80C) • For the 5700L - 5475L section of the main haulage ramp under worst-case-scenario conditions TDB/TWB was predicted to reach 36.8 0C and 27.2 0C – if all potential equipment operate

  23. CONCLUSIONS • A climatic model of a C&F mining area for the active 153 Orebody (4810L) was successfully developed based on mine layouts and the auxiliary ventilation setup • Output data generated through simulations were compared and validated vs. measured data (environmental & activity monitoring) • Environmental and activity monitoring showed concurrent mucking and drilling activities generating some of the highest temperatures • Elevated temperatures also occurred when auxiliary ventilation was not immediately adjusted to meet changes in production activity (TDB=+9.40C/TWB=+3.50C) • The climatic condition within the future 170 Orebody were predicted using the 4810L model transposed to the 5700L  airflow intake TDB/TWB, BP, VRT entered for that deeper level (5700L)

  24. CONCLUSIONS – Continued • Climatic simulations of the future 170 Orebody showed that with the simplified working area TWB = 25.50C would not be exceeded • However, TWB could be exceeded in the individual C&F stopes depending on the mining activities and air volume delivered to the individual stopes • The only area where TWB would be exceeded is along the 5700L – 5475L section of the haulage ramp – if all potential equipment would operate simultaneously • Study showed that providing appropriate auxiliary ventilation distribution able to meet various operating requirements has the greatest role in maintaining adequate environmental conditions

  25. Acknowledgement The authors would like to thank Vale Inco for their permission to present this work and recognize the Ventilation and Engineering Staff of Coleman/McCreedy East Mine for their support and cooperation in collecting data and technical information

  26. Thank You Questions ?

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