HomeBase MetalsNevsun Resources continues to expand Harena with high grade drill results

Nevsun Resources continues to expand Harena with high grade drill results

Eritrea Nevsun Resources has released new assay results from exploration drilling completed on the Harena mining license located 10 kilometers south of the Bisha Mine and processing plant, located in Eritrea.

The drilling forms part of the 2015 Bisha regional exploration program which builds on the highly successful 2014 program.


  • Intersections of high grade massive sulphide in Lower Zone include:
    • HX-050:  1.66% copper, 6.62% zinc, 0.41 g/t gold, 28 g/t silver over 67.2 m including 4.61% copper, 3.43% zinc, 0.99 g/t gold, 63 g/t silver over 22.1 m and 0.22% copper, 8.18% zinc, 0.13 g/t gold, 10 g/t silver over 45.1 m
    • HX-051:  1.09% copper, 3.57% zinc, 0.43 g/t gold, 22 g/t silver over 73.5 m including 4.25% copper, 1.17% Zn, 1.01 g/t gold, 62 g/t silver over 11.0 m
  • Intersections of massive sulphide in Upper Zone include:
    • ​HX-043:  0.63% copper, 5.70% zinc, 0.35 g/t gold, 28 g/t silver over 18.5 m
  • New Gold Zone intersection confirming continuity:
    • HX-045:  7.49 g/t gold, 171 g/t silver over 11.0 m
  • Lower Zone massive sulphide extended 120 m down dip with increasing width and grade
  • Upper Zone extended over 150 m along strike
  • Deposit remains open to depth and along strike

“We continue to have exciting results at Harena. The assays reported demonstrate that the deposit is increasing in thickness and grade with depth as a core of high grade mineralisation is being outlined.  We also continue to see the deposit growing along strike to the south.  These new results bode well for significant further expansion of the resource at Harena,” says Nevsun CEO Cliff Davis.

Three distinct high grade zones of mineralisation being defined at Harena include:

  1. Lower Zone: massive sulphide open at depth
  2. Upper Zone: massive sulphide lens open on strike
  3. Gold Zone: stringer and stockwork enriched gold zone

Lower zone

Holes HX-047, HX-050 and HX-051 were drilled to test down dip of hole HX-040 that returned 1.78% copper, 5.78% zinc over 32.0 m including 8.82% zinc over 20.1 m and 4.19% copper over 11.9 m.

Both holes hit comparable intervals of massive sulphide to that of HX-040 with classic volcanogenic massive sulphide zonation consisting of an upper pyrite – sphalerite zone followed by a lower chalcopyrite – rich zone.

Hole HX-050 is the deepest hole drilled to-date and with hole HX-051 demonstrate that the massive sulphide zone is increasing substantially in thickness with depth.  Borehole Transient Electromagnetic (BHTEM) surveys completed in these and neighbouring holes have defined a large high conductance geophysical plate associated with this mineralisation in what is now being termed the Lower Zone.

This zone appears to be the main core of the Harena deposit based on the thicknesses of massive sulphide encountered, the metal zonation and the high base metal content.  It is still open at depth.

Upper zone

Hole HX-039 and subsequent holes HX-042, HX-043 and HX-049 were step-out holes approximately 150 m to the south of the deposit targeting strong alteration in the host felsic volcanic rocks.

These holes have intersected variable thicknesses of massive sulphide that are very zinc-rich.  BHTEM has defined a large plate associated with this mineralisation that suggests there should be considerable continuation of the mineralisation to the south.  This zone is now termed the Upper Zone and it is open along strike to the south.

Gold zone

Hole HX-045 targeted a gap in the drilling of the stringer mineralization that occurs between the Upper Zone and the Lower Zone.

This hole successfully intersected stringer mineralisation with 7.49 g/t gold and 171 g/t silver over 11.0 m and confirms the continuity of precious metal-rich stringer mineralisation in what is now termed the Gold Zone.

Further expansion of this zone to the south will be the goal of future drilling.

Regional exploration programme

The 2015 Bisha Mining Share Company regional exploration programme is currently focused on three main areas:  expansion of the Harena deposit at depth and along strike; exploring the perimeter of the Bisha deposit at depth and along strike; and, evaluating regional targets on the Mogoraib River License at Asheli and Tekewuda.

Systematic surface and BHTEM surveys in combination with geological and lithogeochemical modeling is being used to successfully guide the exploration effort.

The 2015 Harena exploration results reported are designed to expand the deposit beyond the known resource.

Since drilling was renewed at Harena in mid-2014, the indicated resource at Harena has grown by 1.4 Mt and the inferred resource has increased by 6.1 Mt.  A plan map of the drilling and representative sections are attached at the end of this release.  Drilling in part, is being guided by BHTEM surveys as the massive sulphides (particularly the copper-rich sections in holes HX-040, HX-047, HX-050 and HX-051) give strong electromagnetic responses.

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Chantelle Kotze
Chantelle Kotze is a Johannesburg-based media professional. She is a contributor at Mining Review Africa (Clarion Events - Africa) and has created content for the media brand over the past 6 years.