Damang mine, Ghana - Mining Weekly
Location: The mine is located in south-and to the north of and joining the concession, which is located near the town of .
Brief Description: The mine is an openpit mine, which comprises four openpits and one carbon-in-leach plant with a current capacity of 4.5-million tonnes a year. It is estimated that the current mineral reserve will be depleted in 2020.
Brief History:Fields and Repadre signed an agreement in 2001 to buy Ranger ’s 90% interest in . and Repadre merged to give an 18.9% interest in and Fields a 71.1% interest. In 2011, Fields bought out ’s remaining interest in and the company now owns a 90% stake, with the government of owining the remaining 10%.
Theexpansion was initiated in 2004 to identify additional sources of ore from areas around the main pit. Following further , a feasibility study was initiated to test the feasibility of a cutback to extend the life of the main pit. In July 2005, the pit cutback and started.
Geology/Mineralisation: Theorebody is hosted by a north to north-easterly plunging antiform, developed within Tarkwaian sediments. The main pit is located close to the closure of the antiform, while all other known mineralisation is located on the east and west limbs of the anticline. The mine exploits fresh hydrothermal and oxide mineralisation, in addition to Witwatersrand-style, palaeoplacer mineralisation.
Reserves: Proven and probable mineral reserves as at December 31, 2015, were 21.12-million tonnes, grading 1.43 g/t. The new reinvestment plan will lead to a 72% increase in proven and probable reserves to 1.68-million ounces.
: Mineral as at December 31, 2015, were estimated at 79.61-million tonnes, grading 2.2 g/t .
Method: at is undertaken by conventional openpit methods using Fields personnel and . Owner includes all load-and-haul, blasting, and activities, while contractors are responsible for production , blast-hole charging, stockpile rehandling and grade-control . However, from 2016, load-and-haul, blasting, and activities have become the responsibility of a . From 2017 onwards, two contractors will be used to conduct the of the pit and the now that the reinvestment plan has been approved (see ‘prospects’ below).
Majorand : The plant processes mainly fresh ore, with about 5% oxides, which is sourced from four and existing stockpiles, located on the mine lease.
The plant has been upgraded from four-million tonnes a year to 4.5-million tonnes a year and is a conventional two-stage grinding circuit using a semiautogenous and ball mill combination, with pebble crusher and gravity concentration, followed by a carbon-in-leach recovery process. Gravityis collected and treated by a gravity concentrator and an in-line leach reactor.
The, with additional lifts, supports the life-of-mine (LoM) plan to December, with the Far (FETSF), for which permitting is already in place, extending the LoM from 2017 to 2024. Permitting is in place for a partial lift, with the full permitting being sought from the regulator.
Load-and-haul is undertaken using a standard truck-shovel operation, with excavators in backhoe configuration.
The haulage fleet consists of 26 dump, with an average payload capacity of 91 t each. Off-highway haul ore to the run-of-mine pad, stockpiles and dumps. A fleet of tipper reclaims stockpiled ore and transports it to the treatment plant. Ancillary supporting the drill-and-blast and haulage through and bench , dust and erosion control, and includes bulldozers, graders, and .
Prospects:Fields will invest $1.4-billion to extend the life of its mine from 2017 to 2024.
Over the life of the mine, 165-million tons will be mined, with 32-million tons processed at a grade of 1.65 g/t, resulting inproduction of 1.56-million ounces.
Themine is expected to produce, on average, about 225 000 oz/y of .
The reinvestment plan for the mine is based on mineral resource models that were updated earlier this year and extensively reviewed internally and by external consultants, and .
The reinvestment plan entails a major cutback to the eastern and western walls of the
will be undertaken by two contractors, with negotiations currently at an advanced stage. The contractors are expected to be mobilised early next year.
The reinvestment will also include theof the FETSF, as the existing tailings facility is approaching full capacity.
Stage 1 of the new FETSF is planned for completion by the end of 2017 and will provide 20-million tons of capacity. Further lifts of the FETSF will cater for all tailings for the new LoM.
Only minor capital work will be required on theprocessing plant, which will mainly entail replacing the semi- autogenous grinding mill in 2018.
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