Tag Archives: Ghana

Asante Gold weighs up use of Anaconda Mining SMD narrow vein technology

Asante Gold says it is reviewing a new mining technique, Sustainable Mining by Drilling (SMD), for use at its Kubi gold project in Ghana.

SMD is a two-stage drilling method that enables direct mining of narrow vein deposits. The technology is being developed and commercialised by Anaconda Mining, in collaboration with Memorial University of Newfoundland, and uses technology proven in other industries, Asante said.

Anaconda’s SMD technology placed second in the recent Goldcorp #DisruptMining challenge held on the sidelines of the annual Prospectors and Developers Association of Canada event in Toronto on March 3, 2019.

“This concept is a complete surface mining option with a drilling rig as a main surface piece of equipment used in conjunction with several field-proven downhole technologies,” Anaconda said.

The mining process is divided into two campaigns: drilling the pilot holes and accurately mapping the vein, then enlarging the pilot holes to predetermined sizes to recover the ore.

Using an inclined mast drilling rig, an inclined pilot hole is to be drilled along the centre line of the vein (equidistant between the hangingwall and footwall) with directional drilling system.

Steering the pilot holes live with a survey tool will determine the current orientation and refine the 3D model of the vein used to plan the pilot hole enlargement.

“Once the pilot hole has been drilled, progressively larger hole-openers can be used to drill along the pilot hole’s trajectory up to 2 m,” Anaconda said.

Anaconda said the SMD technology is a “disruptor” in that it reduces the cost to extract ore by 50% over conventional underground narrow mining techniques; it places the operator in a safe location on the surface; can access areas not open to conventional mining; reduces the environmental footprint; and by passes the crushing and grinding circuits by moving the +/-2 mm drill cuttings in a slurry direct to the mill.

Douglas MacQuarrie, President and CEO of Asante Gold, said: “The new SMD mining technique slashes the mining costs, development time and capital required to take near-surface gold deposits to production.

“Our Kubi Main Zone gold resource is located in one of the best and safest gold mining destinations in the world, is road and power accessible, has an average width of 2 m, is near vertical, and appears to be well suited for the application of this technique. Previous metallurgical tests on Kubi mineralisation gave 35% to 40% recovery of the contained gold by gravity concentration from a coarse grind, which suggest a similar recovery might be expected directly from the SMD drill cuttings, giving a potential source of early cash flow. We are looking forward to the development and commercialisation of the SMD technology and its potential application at Kubi.”

AngloGold Ashanti blasts off at Obuasi Redevelopment project

AngloGold Ashanti says the first week of underground development blasting has been completed at its Obuasi Redevelopment project in Ghana, as work to pour first gold by the end of the year gathers momentum.

The first blast, at about 7 pm on February 1, advanced development by around 4.2 m on the 2,700 level, which is accessed through the Obuasi Deeps decline from surface and is just over 700 m vertically below the decline portal, the company said. Benching and a number of additional face blasts have taken place since, with more than 14 m of advance recorded.

AngloGold Ashanti announced early last year it would invest $495-$545 million to recapitalise the iconic mine in Ghana, to develop its 6 Moz of high-grade reserve. The project will see Obuasi transformed into a modern, mechanised mine that will produce, on average, 350,000-400,000 oz/y of gold at all-in sustaining costs of $725-825/oz during the mine’s first decade of operation, according to AngloGold. Higher grades in the second decade of operation will see production improve further, it added.

AngloGold Ashanti, Chief Executive Officer, Kelvin Dushnisky, said: “The first blast was a significant milestone in transforming this important mine into a modern, productive operation. Our investment in Obuasi gold mine’s redevelopment will ultimately make this a key asset for Ghana, and for AngloGold Ashanti’s portfolio, for the long term.”

The project remains on track to produce its first gold by the end of this year, with ramp-up expected during 2020.

AngloGold Ashanti says it has committed to ensuring significant local content in the mine’s development and operation, through employment at all levels and procurement, notably through the creation of a joint venture between Australia’s AUMS and Ghana’s Rocksure, to undertake Ghana’s underground mining contract.

Development of the project is progressing as planned and it is expected that capacity will ramp up to around 1 km/mth of linear advancement in the second half of the year. Stoping operations are expected to start in the December quarter of this year as new production areas are accessed.

DRA Global helps Asanko gold mine surpass 5 Mt/y capacity

DRA Global recently implemented an Advanced Milling Control System, using the MillSlicer instrument, on the Asanko gold mine in Ghana.

Asanko is a large scale, multi-pit asset located on the Asankrangwa belt in Ghana. Built in 2015 by DRA Global, ahead of schedule and within budget, first gold was poured in January 2016 and commercial production commenced in April 2016. The mine is now owned 50:50 by Asanko Gold Mining and Gold Fields.

DRA said: “Operations at Asanko prioritise efficiencies, with minimal downtime. Unplanned or forced mill stoppages and breakdowns can often lead to costly setbacks for overall mine operations.

The DRA Global technical processing specialists collaborated closely with the Asanko owner’s team to develop a control system solution that is able to produce real time reporting and enable the mill operators to better optimise the milling process.”

Val Coetzee, DRA’s Senior Vice President Process, said: “This MillSlicer Control instrument provides accurate signals via a number of strategically positioned vibration sensors that are used by DRA’s comminution and control specialists to develop bespoke control systems, specific to an operation. The programme allows for accurate mill charge toe-angle measurement and real time polar plot determination, which is used in the customised control system.”

The milling control system, which was commissioned by DRA in August 2018, uses propriety “rule-based algorithms” assisting the mine’s operation with superior control, maximising energy efficiency and ensuring continual optimal mill performance despite any changes in mine fragmentation or ore type variances, according to DRA.

Coetzee said: “DRA is able to provide remote operational support, data analysis and reporting to assist clients in reducing liner damage, media consumption and ensure that mill operators efficiently maximise throughput at all times.

“This MillSlicer hardware and the DRA Advanced Control System, in conjunction with a number of other initiatives relating to open circuit modifications, use of cameras and feed blending, have successfully contributed to the performance excellence of the Asanko processing plant in recent months.”

Russell Bradford, SVP Metallurgy at Asanko, said: “The MillSlicer hardware has enabled the Asanko team to optimise the mill’s performance by ensuring we always have the right blend of ore at the right tonnages in the mill. Since this technology was implemented, the Asanko processing plant has consistently delivered above its 5 Mt/y design rate.”

The Asanko mine is a 50:50 joint venture between Asanko Gold Mining and Gold Fields managed and operated by Aasnko. In 2018, the mine is targeting 200,000-220,000 oz of gold at an all-in sustaining cost of $1,050-$1,150/oz.

AUMS wins contract at AngloGold Ashanti’s Obuasi mine in Ghana

African Underground Mining Services (AUMS) has been awarded a $375 million underground mining services contract at one of West Africa’s oldest mines, Obuasi, in Ghana.

The five-year contract at the AngloGold Ashanti operation will see AUMS team up with Rocksure International, a Ghana-based mining contractor, under a 70:30 joint venture.

AUMS, owned 50:50 by Ausdrill and Barminco Holdings, will provide a full suite of underground mining services at Obuasi, with major capital equipment supplied by AngloGold. Works are expected to commence in the March quarter, with some 550 people due to be employed during the project term.

Blair Sessions, AUMS Chief Operating Officer, said the company was pleased to extend its relationship with AngloGold, adding AUMS and Rocksure would “deliver on this project using modern and efficient mining methods, supporting local suppliers and providing employment and training opportunities to Ghanaians”.

Graham Ehm, AngloGold Executive Vice President – Group Planning and Technical – said the contract award was a major milestone towards recommencing production at Obuasi and delivering on outcomes that would benefit the national, regional and local economies.

Earlier this year, AngloGold said it would spend $450-500 million to redevelop Obuasi into a modern, productive mining operation. The mine had been in limited operating phase since 2014.

Since commencing operations in Ghana eight years ago, AUMS has trained over 1,200 Ghanaians through a range of mining, engineering and apprenticeship programmes, AUMS said. Ausdrill, meanwhile, has a 27-year history in the country through its African Mining Services (AMS) subsidiary.

AUMS and AMS, combined, employ more than 1,800 people in Ghana across five projects. The two businesses have generated around A$2.8 billion ($1.99 billion) of revenue in the country.

Ausdrill is currently in the middle of taking over AUMS JV partner Barminco in a deal that values the latter’s equity at A$271.5 million. Last week, Ausdrill shareholders approved the acquisition, paving the way for the deal to be completed by the end of the month.