AIM-listed Africa iron ore and manganese development company Ferrex recently announced a positive update from its 85%-owned 92 390 ha Nayega manganese project in northern Togo. The project has the potential to be developed into a low capital and operating cost opencast manganese mine in the near term.

Results to date from initial metallurgical test work have been positive with a simple scrubbing, screening, crushing and gravity circuit producing a saleable manganese concentrate at economic grades. Additional test work is now planned to further optimise recoveries and grade to allow finalisation of the best process route for Nayega. Based on the current flowsheet, the company estimates that the total capital for the project will be less than US$15 million (about R124.35 million), which will allow it to produce up to a maximum of 250 000 tpa of manganese product. This low-capital requirement will be of great benefit to the project’s economics.

Additionally, independent studies have shown that there is more than 350 000 t of backload availability on the nearby Highway 1 that would be able to transport any product produced to the Port of Lome in southern Togo, where existing manganese blending operations are already in place for containerisation and shipping to China. This will also substantially reduce the capital and operating costs of a mining operation at Nayega.

“Furthermore, regional exploration is also under way and is focused on 47 targets surrounding the main Nayega deposit. A total of 30 targets have been investigated at present and these indicate interesting manganiferous outcrops. Although exploration is at an early stage, we hope to delineate additional resources at these areas, which will enable us to increase the scale of this already exciting project in the future,” says Ferrex MD Dave Reeves.

“This is a very encouraging development update following close on the heels of the recent maiden resource at our Nayega project, which we are aiming to be our first near-term low-capex mining operation to bring cashflow to the company.”

The project in summary

  • maiden inferred resource of 6.3 Mt @ 14.1% manganese
  • ore easily amenable to low-cost upgrade through screening and gravity
  • resource estimated on results of 77 pits dug on 100 m centres along east-west lines spaced 200 m apart
  • further infill pitting completed on 100 m x 100 m centres – results targeted for the third quarter (Q3) 2012 to allow potential resource upgrade to indicated classification
  • deposit is amenable to development as a shallow opencast operation with no waste stripping required
  • metallurgical test work results are due Q2 of 2012; the scoping study will commence immediately after
  • definitive feasibility study is on track to be completed before the end of 2012
  • Nayega has access to good infrastructure; there is direct road access to the major deepwater port of Lome 600 km to the south of Nayega.
Metallurgical test work

Initial metallurgical test work has been conducted under the guidance of Consulmet, a South African gravity processing specialist. The test work has consisted of screening and dense media separation processes.

The screening results show that when the -850 micron fines are removed, a mass recovery of 44% and a manganese recovery of 86% were achieved. This results in the grade of the feed material being upgraded from 14 to 28% via simple scrubbing and cleaning, while capturing the bulk of the manganese mineralisation.

A series of heavy liquid separation tests were then run on the screened product utilising both uncrushed and crushed material. The best results were obtained by crushing the entire +850 micron screened product to -6 mm. An average mass recovery of 56% and a manganese recovery of 75% were achieved. This resulted in an average product of 38% being produced. This equates to a standard South African manganese export ore grade that is readily traded in the market.

From the results to date, it is believed that the process at Nayega has the ability to be optimised in respect to both recoveries and concentrate grade produced. As a result, another round of test work will now be undertaken to finalise the process route for the bankable study.

Cost estimates

Initial scoping cost estimates have now been received for the majority of the operating and capital costs components of developing a mine at Nayega. These costs are broadly in line with previous expectations and will form the basis of the full scoping study, which is targeted to be finalised with the next round of metallurgical test work in Q3 2012. Initial figures suggest that the capital cost will be less than US$15 million, which will benefit project economics and allow multiple sources of finance to be investigated.

Infrastructure investigation

Initial investigations have shown that the deposit is located in a rapidly developing area. A new road is currently being built within a few kilometres of the mine from the regional centre of Dapaong. In addition, power lines are planned to the same area at a rated capacity of 33 kVA.

US Aid studies suggested that in 2009, there was up to 350 000 t of empty backload capacity on the Dapaong to Lome route, the main import route from neighbouring Burkina Faso, with recent figures suggesting that this capacity is increasing by 10% per annum. This empty capacity will be targeted to transport the product back to Lome where manganese from Burkina Faso is already transported to a packing yard. This facility provides a receiving, containerisation and dispatch service. In addition, the Port of Lome has recently announced the construction of a third container pier of 450 m in length to facilitate the increased demands from the area.

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