Red 5 Tailings Compromise and Forward Planning... This company cannot be trusted...too risky and compromising plan at the expense of the local people, the local land and the local culture!!!!!! As reported, on 25 April 2013 the tailings dam developed a crack which progressively expanded to 250m in length along the axis of the wall, with a downstream vertical displacement of 3m – a classical circular failure. Immediate actions and those completed during the following month led to preservation of the intrinsic value of the asset with no discharge of any effluent or tailings to the environment occurring. Subsequent to the completion of the remedial works the Company received a Cease and Desist Order from the Philippines Mines and Geosciences Bureau Central office instructing the Company to cease milling operations and to no longer use the failed tailings dam. The Company has complied with the order fully and has worked with the various regulatory bodies to have the order removed. This remains ongoing. With the tailings dam remedial works complete to the extent needed to ensure the facility is stable, in a care and maintenance status. It has not been fully closed, with capping to ensure no risk of longer term erosion still outstanding. The Company has devised a new operating strategy to handle tailings involving a three step process as follows: Stage 1 – Interim small capacity lined tailings storage facility A small lined tailings storage facility is proposed to be constructed downstream of TSF 4 to accept slurry tailings for a period of approximately 4 months. The facility is proposed to be lined with a plastic liner to avoid the potential for saturation of the underlying foundation and or the embankment, which may have been a causal contributing factor behind the TSF 4 failure. A construction and permitting timeframe of up to 3 months is anticipated. Stage 2 – Cemented paste tailings and co-deposition with waste Concurrent with construction of Stage 1 above the processing plant will be modified to allow for the installation of a thickener (and filter) and a cement paste plant to make a product which would allow for deposition with normal mine waste. The paste product will be trucked from the process plant to the co-deposition area which is planned to occupy the entire footprint occupied by the current TSF4, TSF 3, and Stage 1 tailings storage facility. Location proximity to the processing plant and open pit will minimise transport costs. In particular, there will be a reduction in waste transport by 150m elevation and 1.5km laterally compared with the current operation. The plant modifications proposed would in any case be implemented in 3 to 4 years time when the mine transitions to underground mining, as the mining method calls for paste fill to fill the mined out voids within the ore body. The current dump location identified may have up to 6 million bcm of capacity thus it is anticipated it can accommodate 18 months to 2 years tails production as a minimum however this remains to be confirmed through test work and engineering studies currently under way. Stage 3 – Ultimate valley style tailings storage The long term solution for the Company involves a new dedicated facility located outside the current foot print of the mine site. An ideal site has been chosen 800m south of the open pit and preliminary estimates suggest it is readily expandable with a deemed maximum capacity of up to 25 million tonnes of tailings. Whilst this is an ideal outcome it has inherent risk from a timing perspective given it requires acquisition of land from over 100 separate landowners plus permitting and construction, all of which have a degree of uncertainty attached. The Company believes this process could be completed in 12-18 months including 6 months contingency to allow for uncertainty.
Posted on: Tue, 06 Aug 2013 23:36:03 +0000
Trending Topics
Recently Viewed Topics
© 2015