Wigu Hill, Tanzania
The Wigu Hill REE Project is a light rare earth element deposit and a large carbonite complex with bastnaesite mineralization. The licence area covers 142km2. Initial grab samples yeilded results as high as 27.25% TREO. Montero released an initial NI 43-101 Inferred resource estimate of 3.3Mt at 2.6% LREO5 including 510K @ 4.4% LREO5 on 2 of 10 possible drill targets. Further exploration drilling to add to the current resource is underway.
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Location
The Wigu Hill Property is located in Tanzania, 170 km south-west of Dar es Salaam, and 68 km south of Morogoro, the nearest major regional centre (straight line distances). The project area can be accessed by the all-weather Dar es Salaam-Marogoro road and it is 7 km from the TAZARA railway line with the nearest siding at Kisaki just 12 km away.
History
The carbonatite complex has been know since the 1950s and sampled many times by various mining and scientific organisations. A summary is listed below:
- Early 1950 – discovery of the deposit by the geological survey
- 1957 – New Consolidated Goldfields examined the hill for rare earth
- 1973 - The area was explored by Molycorp Minerals
- 1987 – Tanzanian-Canadian Agrogeology project examined the area for phosphate potential
- 2000 – The area was examined by P.R. Siegfriend
- 2007 – BGR assessed the project on behalf of the Tanzanian government
- 2008 – Montero entered into an agreement with RSR in 2007
- 2009 - Reconnaisance sampling and mapping of the Wigu Hill complex commenced
- 2011 - Montero listed on the TSX.V in February and exploration commenced
Geology
The Wigu Hill Property is a large, REE enriched carbonatite with dolomitic vein system which cut into Precambrian gneisses. The deposit type would be best described as a high level, carbonatite hosted REE dike deposit. The principally coarse-grained carbonatite dikes largely contain dolomite, bastnaesite and quartz.
Mineralization is mainly concentrated in the carbonatite dykes although the surrounding country rocks appear to have low grade REE mineralization of unknown extent and grade. The REEs occur predominantly in the minerals bastnaesite, monazite and synchysite, although others such as parasite and goyazite have also been encountered. The carbonatite dykes that host the REE are typically 0.6-8.0m wide and can be traced intermittently over distances of over 700m.
The deposit is a LREE dominated which is characteristic of most carbonatites. Sampling to date has revealed grades averaging over 7% total rare earth oxide (TREO), with individual samples up to 26.2% TREO.
Exploration
Montero has embarked on a detailed mapping, trenching and drilling program on the prospect to better define the setting, distribution and nature of the mineralization. This has led to the delineation of 10 target areas; some of which advanced exploration work has been completed and is underway; Twiga, Tembo, Tumbili and Nyati
Twiga
- Surface dimensions of 500m by 150m
- The area was drilled, trenched and grab samples taken
- 14 diamond drill holes were drilled for 1465 m
- Significant Results include: Trench CC2 10.23m @ 13.28% TREO including 3.65m @ 18.18% TREO and 0.73m @ 27.25 TREO and Drillhole TW003R: 20,76m @6.23% TREO including 4.03m@ 11.91%TREO and 1.39m@ 16.68% TREO
Tembo
- Surface dimensions of 500m by 150m
- The area was grab, trench and drill sampled
- 5 diamond drill holes were drilled for 540 m
- Significant Results include: Trench 7: 1.75m@ 4.92% TREO including 6.45m@ 9.27% TREO and 2.00m @ 15.48% TREO and Drillhole TE001: 6.95m @ 3.59% TREO including 5.66% TREO
Tumbili
- Surface dimensions of 1200m by 500 m
- The area was drilled, trenched and grab samples taken
- 6 core drill holes were drilled for 1,525m
- Significant Results include: Trench 1: 18.0m @ 3.02% TREO with a maximum value of 2.3m @ 9.44% TREO and Drillhole TUM0002: 80.0m @ 1.04% TREO and TUM0002: 253.8m @ 0.61% TREO
Nyati
- Surface dimensions of 800m by 400 m
- The area was mapped and grab samples taken
- Significant Results include: Sampling from the NE Section: 2.51% TREO to 18.21% TREO with the average value from 55 samples returning 10.43% TREO and from the SW Section: 1.95% TREO and 13.03% TREO with an average value from 45 samples returning 5.85% TREO.
Chui
- Surface dimensions of 300m by 100 m
- The area has been mapped and remains a future target of exploration





















