Report On A Geological Visit To An Area, About 10km South Of The Town Changara, In The Tete Province Of Mozambique
The licence area is approximately 15,700 ha in size and is about 10 km south of the town Changara in the Tete Province. The Luenha river flows through a portion, in the north-western part of the area. The area is currently protected from artisanal miners by armed guards of the Police Force. The purpose of the visit to the area was to get a better understanding and to determine whether the area could be a viable mining operation for gold.
Outcrops of a pink granite-gneiss is visible over a large extent of the area. All of the primary gold deposits in Mozambique were traditionally thought to be of Archaean or early Proterozoic age, although this has not been verified by age dating. Nevertheless, the gold deposits occur in the northern part of the country that is underlain by Pre-Cambrian basement. The genetic type of gold mineralisation has been recognised to be a hydrothermal quartz-gold veins and stockworks in shear zones.
Various open pits are present, in which the primary biotite-quartz schists, which has been recognised to be the primary ore vein, are visible. Fig.1 is a typical example of the biotite-quartz schist.
On the Google Earth map, various tectonic fabrics are visible indicating more than one tectonic episode. Observations of the primary reef in the pits of the artisanal miners, indicated a granite-gneiss capping of about 2m followed by a reef zone of also about 2m, consisting of the biotite-quartz schist.
By closer investigation, it is clear that the primary gold mineralisation is hosted by sheared and weathered mica gneisses of Archaean age, in horizontal quartz veins. From a structural point of view these schists( original quarts veins) forms a synformal structure with the veins lying parallel underneath the granites.
Due to weathering these schists form alluvial schist material as well as alluvium. Gold is panned from the crushed quartz vein fragments in the nearby Luenha river. The Artisanal work team reports that the gold grade is approximately 5g/t. Since very little exploration work has been carried out the Samora area can be classified as a very interesting area.
Gold showings around Changara – Luenha river several thousand artisanal miners are estimated to produce 50 – 60 kg gold annually by digging and panning the lateritic soil and alluvium in river valleys.
A sample of the biotite-quartz schist was submitted to the Council of Geoscience of South Africa to do an electron microscopy analysis on the sample and identify the minerals that were identified visibly as a gold flake.
In the next section the analysis is shown.
At an in situ grade of 4 g/t, it is estimated that the area consists of 41 million ounces of gold.
The assumption of 4 g/t and 41 million ounces is based on the fact that the area of the concession is 15,700 ha in size and 90 percent of the area is underlain by the pink granite – gneiss with the gold bearing quartz – biotite, of almost 3 metre thick in places, underneath it as can be seen in the picture.
The top of the reef is starting at the shoulder of person standing at the back and continues to just below their feet. A conservative thickness of 1 metre was used across the whole concession area for the resource estimation. In the next image a small TLB is busy breaking the granitic overburden to get to the gold bearing schist. Both the granite overburden and the schist are very brittle and easy to break with fairly small machines.
The following image is showing some of the gold recovered where the small TLB was working.