HomeEast AfricaContinued high grade gold at Rift Valley Resources Miyabi project

Continued high grade gold at Rift Valley Resources Miyabi project

Tanzania – ASX-listed Rift Valley Resources has confirmed further high grade results from drilling at its 100% owned Miyabi Gold Project in Tanzania.

The Miyabi gold project, located 200km south of Mwanza within the Lake Victoria Goldfields of Tanzania, lies 50km east of Acacia Mining’s 4.5 Moz Buzwagi gold mine and 30km south of Resolute Mining’s 0.9 Moz Nyakafuru project.

Rift Valley Resources commenced drilling at its wholly owned Miyabi Gold Project in Tanzania last week
Rift Valley Resources commenced drilling at its wholly owned Miyabi Gold Project in Tanzania last week

Drilling is now complete and all assays returned. The latest results confirm the presence of a thick high grade shoot at the high grade Dalafuma prospect, discovered by Rift Valley in 2011, including the latest intersection of:

  • MBRC421 – 18m at 6.90 g/t from 111m, including 3 m at 21.4 g/t from 126m
  • This result is along strike from previously announced intersections of:
  • MBRC401 – 27m at 3.64 g/t from 78m (2015 drilling), including 3m at 21.7 g/t from 93m
  • MBRC349 – 16m at 11.96 g/t from 65m (2012 drilling), including 5m at 27.7 g/t from 71m
  • Broad zones of shallow mineralisation were also intersected at Dalafuma North West including:
  • MBRC419 – 30m at 0.90 g/t from 72m, including 9m at 1.67 g/t from 75m

This strongly mineralised zone remains open to the east and is along strike and down dip of previously announced intersections of:

  • MBRC398 – 23m at 4.22 g/t from 45m
  • MBRC396 – 42m at 0.68 g/t from 18m, including 6m at 2.51 g/t from 18m

“These results confirm the potential of the Dalafuma area to host a major gold deposit. The excellent results will be incorporated into the maiden resource estimate at Dalafuma to be completed in the September quarter,” Rift Valley Resources MD Geoff Gilmour says.

Current exploration programme

Rift Valley’s initial work program comprised 27 RC drill holes in four prospect areas. All results have now been received and multiple high grade intersections have been returned from the Dalafuma area.

Results from the other prospect areas identified anomalous mineralisation but do not warrant further assessment at this stage.

Dalafuma prospect

Mineralisation at Dalafuma is hosted within two separate structures within mafic lithologies.

The main lode occurs within a well-defined shear zone and is associated with disseminated and stringer pyrite mineralisation within a zone of quartz veining and silicification. The high grade mineralisation extends to within a few metres of surface and remains strongly open at depth.

Intersections from the current program include:

  • MBRC421 – 18m at 6.90 g/t from 111m (including 3m at 21.4 g/t from 126m)
  • MBRC401 – 27m at 3.64 g/t from 78m (including 3m at 21.7 g.t from 93m)

Hole MBRC420 was drilled to 200m but steepened severely and has not tested the main high grade structure.

Intersections from previous drilling in 2012 at Dalafuma include:

  • MBRC349 – 16m at 11.96 g/t from 65m (including 5m at 27.7 g/t from 71m)
  • MBRC382 – 28m at 6.7 g/t from 16m
  • MBRC331 – 18m @ 12.0 g/t from 46m

A separate zone of mineralisation has been discovered at Dalafuma NW. Gold mineralisation occurs within a silicified and altered shear zone adjacent to a broad gossanous ironstone.

Further work is required to understand the geometry of the zone but it remains strongly open at depth and along strike to the east. Better intersections from the current programme include:

  • MBRC398 – 23m at 4.22 g/t from 45m
  • MBRC419 – 30m at 0.90 g/t from 72m (Including 9m at 1.67 g/t from 75m)
  • MBRC396 – 42m at 0.68 g/t from 18m (Including 6m at 2.51 g/t from 18m)

The substantial results from the current program will allow a Mineral Resource estimate to be prepared for the Dalafuma prospect. This is expected to provide a material increase to the 520 000oz Mineral Resource already defined at the project.

Future work

Results from the recent drilling have been compiled for inclusion into a Mineral Resource estimate for the Dalafuma deposit. In addition, all other deposits will be re-estimated and reported under JORC 2012 guidelines. The resource estimates will be completed early in the September quarter.

Detailed geological interpretation has commenced to determine the controls on mineralisation at Dalafuma. This will be used to guide future drilling at the project. High priority targets remain for extensions to both the main zone and Dalafuma North West and drilling is expected to resume during the September quarter to test the targets.

An extensive blanket of barren ferricrete or laterite (typically 5m thick) overlies the Dalafuma deposit. The ferricrete prevents any surface geochemical signature from occurring, with the result that drilling is required to determine the basement geochemistry.

Large areas of the project covered with the ferricrete blanket were previously explored using soil geochemistry. It is now clear that this was not effective and that potential remains for further discoveries like Dalafuma. The company has commenced assessment of available geophysical and geological data to allow a more regional exploration plan to be developed.

This will lead to additional RAB and aircore drilling being planned at the project.

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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.