IM 2016 June 2016 | Page 69

PASTE- GOLDER_proof 25/05/2016 11:14 Page 2 Paste Supplement the 7 in slump paste produces a higher strength for a given binder content (when comparing interpolated results) the data clearly shows that the thickened tailings when combined with modest amounts of 90% BFS/10% NPC binder does yield UCS values suitable for typical backfill strengths. It is postulated that the higher than expected strengths obtained with CTT are attributed to the high sedimentation rate of the TMM tailings. Blast furnace slag is typically known to have a delayed onset of strength during curing. During the first few days after placement, it is believed that TMM tailings, which have a high settling rate, are continuing to consolidate from the initial 73 wt% solids. The slow onset binder reaction would then allow settling to continue after placement. Advantages of CTT over paste Figure 2: Comparison of tailings with 90% BFS/10% Normal Portland Cement at a 7 in slump and 73 wt% solids Summary Similar to the ore that is processed, all tailings exhibit unique properties. Understanding how the tailings react to different binder types and challenging conventional thinking, can lead to unconventional, more optimal backfilling strategies. The results illustrate that evaluating different applicable binder blends should be an integral part of the backfill test program. IM Water, a precious resource GEHO® PD slurry pumps GEHO® PD slurry pumps Water is a precious resource, the lifeblood of the planet. Water is also a resource at risk. GEHO® high efficiency pumps allow the transportation of high solid content tailings. Users enjoy significant energy savings, not to mention dramatically reduced water consumption and extended dam life. To find out more about how we can help improve your operational and sustainability performance, contact us at: [email protected] www.global.weir Minerals 1916 - 2016: Innovating for 100 years. Innovating for you. Copyright © Weir Minerals Netherlands b.v. All rights reserved. WEIR and WEIR (logo) are trademarks and/or registered trademarks of Weir Engineering Services Ltd. GEHO is a trademark and/or registered trademark of Weir Minerals Netherlands b.v. The advantages of CTT over paste are substantial: 1. Capital cost savings: The CTT backfill process does not require the second stage of dewatering, a repulp stage, and also simplifies pumping/ piping requirements. By eliminating the second stage dewatering and repulp stages, a substantial filtration and paste mixer circuit is removed from the process. The lower density slurry produced from the CTT process reduces pipeline friction losses, allowing for the same pumping system to deliver CTT slurry to more distant underground locations. 2. Operating cost savings: For this specific case, CTT represents a 65% reduction in power consumption, a 50% reduction in operations labour costs, and a 69% reduction in projected maintenance costs consisting of spare parts and maintenance personnel.  One potential down side to CTT compared to paste is the additional water that is being transported underground. After placement of the CTT much of this extra water will bleed off the material as expected, and consideration will have to be made for dealing with this water within the stope, and within the mine. Additional drainage features may be required within the stope in order to divert the bleed water to a mine sump.