Geology and Aerial View

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North River Resources holds 100% of the Namib Lead Zinc Project (NLZM), which is centred on the underground Namib Lead Mine which was previously operational from 1968-1991.

The project has a current JORC resource of 1,250,000 tonnes, with resulting underground in-situ metal inventory of:

  • 30,709 tonnes of lead
  • 80,640 tonnes of zinc
  • 1.76 million ounces of silver

The NLZM is located 25km from the town of Swakopmund and 55km from the port of Walvis Bay.


Three ore bodies were mined previously, namely South, Junction and North ore bodies. The bulk of production was from the South and Junction ore bodies which were developed to 7.5 and 7 Level respectively (each Level being approximately 30m). The North ore body was developed to 2 Level.


Additional occurrences of mineralisation are known at the N20 prospect and at numerous other surface gossan occurrences within the project area.


The North River team has made considerable headway in obtaining legacy information relating to the operations of the mine from 1968 to 1991. This includes diamond drill data that was conducted during that period and prior to operations commencing in 1969. The information was obtained by the discovery of archival reports and plans from a number of different sources in Namibia, as well as interviews with individuals associated with the mine.


The Board believes that the mine produced approximately 700,000 tonnes of ore (calculated from North River's 3D models of the mine voids), producing over 100,000 tonnes of lead and zinc concentrate, and over 1,000,000 ounces of silver. After net smelter returns the Board calculates that this would have yielded revenues in excess of $100 million at current commodity prices.
The Company has access to bore hole logs and assay data relating to surface diamond drilling programmes conducted at Namib in 1956 and 1966, which demonstrate the potential for a number of intercepts up to 100 metres below the base of the historic mine workings, as well as some high grade intercepts at the Northern ore-bodies.


The lead-zinc mineralisation at NLZM and related prospects is thought to have been a primary stratabound sulphide deposit which has subsequently been metamorphosed and deformed. The intense metamorphism and deformation of the area has remobilised and re-deposited the primary sulphide mineralisation in structural traps which are however still largely stratabound.


The mine is free of water and a total of 600 metres of channel sampling of key exposures has been completed. This is predominantly in the lowest parts of the mine in the Junction and South sections and on strike extensions to the mineralisation at higher levels of the mine.


Preliminary metallurgical testwork was completed on grab samples retrieved from newly exposed mining areas. These samples were selected at random and were submitted for analysis and flotation testing. The total sample was small and may not be representative of the eventual run of mine ore however the results were highly encouraging with high recoveries, fast float times and achieving a 56% zinc concentrate. Only two tests were run due to the small sample size and so there is considerable scope to improve both recoveries and concentrate grades.


A Mine Development Plan (‘MDP’) was completed in June 2014 which demonstrated that the project has good economics based on the current resource. The MDP sets out an estimated payback on the Project for a 250 kilo tonnes (kt) per annum plant of just 1.4 years, based on a Mineral Inventory of 425kt of Indicated Resource, and 234kt of Inferred Resource.
A subsequent Mineral Resource Estimate for Namib was published in September 2014 and is detailed below:

JORC Resource

Fresh Ore (tonnes and grade at 1% Pb+Zn cut-off grade)
Classification
Area
Tonnes*
Pb %
Zn %
Ag (g/t)
Indicated

Underground

877,000

2.7

6.0

44.4

Inferred

Underground

372,000

1.9

7.5

42.1

 

Tailings (tonnes and grade at 0% Pb+Zn cut-off grade)
Classification
Area
Tonnes*
Pb %
Zn %
Ag (g/t)
Measured

Tailings

260,000
0.3
2.2
7.5
Indicated

Tailings

350,000
0.3
2.1
7.7

 

* Tonnages have been rounded to the nearest 1,000 tonnes to reflect an estimate

Click here to view the schematics relating to the Mineral Resource Estimate published on 19 September 2014 and 12 December 2013.

 

Click here to view the Company's Mine Development Plan, Envionmental Impact Assessment, Appendices and other associated documents.