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Otjikoto mine, Namibia

17th March 2017

By: Sheila Barradas

Creamer Media Research Coordinator & Senior Deputy Editor

     

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Name: Otjikoto mine.

Location: The Otjikoto mine is located about 300 km north of Windhoek, in Otjozondjupa province, in Namibia. 

Holding and Controlling Company: The Namibian Ministry of Mines and Energy granted Auryx Gold Namibia, later renamed B2Gold Namibia, the Otjikoto mining licence, ML 169, in December 2012. The company is indirectly owned by B2Gold (90%) and Namibian empowerment company EVI.

Brief Description: Otjikoto is an openpit gold mine.

Brief History: There is no recorded history of gold-focused exploration activity within or adjacent to the Otjikoto mine until the deposit was discovered by Avdale Namibia in 1999, as a result of a base metal exploration programme initiated by Anglovaal Mining in 1995. Between 1999 and 2011, a series of operators completed numerous airborne and ground geophysical and geochemical surveys and drilled 305 rotary air blast, 458 reverse circulation and 624 diamond drill holes totalling 173156 m on the Otjikoto Mine. 

The Wolfshaag, Otjikoto, Gerhardshausen and Okaputa Nord I farms were acquired and consolidated in 2011 by Auryx Properties Holdings, which was legally renamed to B2Gold Namibia Properties in July 2012.

The construction of the Otjikoto mine was completed on budget and ahead of schedule in early December 2014. On February 28, 2015, the mine achieved commercial production, ahead of schedule. The planned mill expansion was completed in September 2015. 

Products: Gold.

Geology/Mineralisation: The Otjikoto project is located within the Neoproterozoic Damara mobile belt, which forms part of the Pan–African mobile belt system. The deposit falls under the general classification of an orogenic gold deposit and occurs in a similar stratigraphic position as the Navachab gold mine deposit.

The Otjikoto deposit is hosted within amphibolite-grade metasediments of the Okanguarri formation. The OTC albitite-hornfels unit hosts most of the mineralised vein system and is underlain by a distinct marker horizon, the unmineralised OTB calcitic marble.

Gold in the main Otjikoto deposit is hosted by a north-north-east-striking sheeted sulphide (+ magnetite) –quartz and carbonate vein system. The sheeted veins and related gold mineralisation occur in a series of distinct en-echelon zones oriented at about 10° to 20° north-north-east and plunging at 10° to 15° (average 12°) to the south-south-west. The bulk of the mineralisation occurs in the Central and West shoots. Vein concentrations range from 1 to 30 veins a metre, with higher vein concentration within the shoots. The mineralised system has been traced over a strike length of 2.3 km and to 475 m below surface.

Reserves: Total attributable probable mineral reserves as at December 31, 2015, were estimated at 25.88-million tonnes grading 1.28 g/t gold.

Resources: Total attributable indicated mineral resources as at December 31, 2015, were estimated at 33-million grading 1.37 g/t gold. Inferred mineral resources have been estimated at 1.58-million tonnes grading 4.45 g/t gold.

Mining Method: Openpit.

Major Infrastructure and Equipment: Run-of-mine ore from the openpit operations is delivered by front-end loaders or 100 t trucks to the primary crusher. The ore is fed to a crushing plant, which consists of a gyratory crusher and conveyor system that feeds the coarse ore stockpile. Material is reclaimed from the stockpile and treated in a grinding circuit comprising a primary semiautogenous mill and a secondary ball mill. The entire ball mill discharge stream is treated in a gravity concentration circuit for recovery of coarse-free gold. The gravity concentrate is processed in an intensive leach circuit. 

The gravity tailings product is thickened to 45% solids and treated in a cyanide leach circuit. The leach product stream is pumped to a carbon-in-pulp (CIP) circuit for recovery of gold in solution. The tailings stream from the CIP circuit is treated in a cyanide destruction circuit using the Sulphur dioxide/air process, before being pumped to a lined tailing storage facility. Gold is recovered from the CIP circuit loaded carbon in a split Anglo American Research Laboratories elution circuit. Gold solutions from the gravity intensive leach circuit and elution circuit are treated in an electrowinning process followed by smelting to produce doré bars. 

Prospects: The Wolfshag openpit will continue to produce higher than average grade ore for three to five years, depending on the transition to underground mining. Life-of-mine production plans for the Otjikoto project, incorporating the Wolfshag openpit and underground mines, have been completed for various options and will be further refined as the detailed geotechnical, hydrogeological and design studies are completed in the first quarter of 2017 (openpit) and first half of 2017 (underground). Ongoing studies are leading B2Gold to re-evaluate the openpit and underground interface.

Contact Person: Manager – investor relations and public relations Katie Bromley.

Contact Details:
B2Gold
Tel +1 604 681 8371
Fax +1 604 681 6209
Email: kbromley@b2gold.com
Website http://www.b2gold.com

 

 

Edited by Creamer Media Reporter

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