Batovi Diamond Project – Why Mato Grosso?
Artisanal alluvial mining has been seasonally active in the Central-West Region of Brazil since diamonds were found in the early 1960’s. A large number of stones have been recovered from the alluvial beds of several rivers surrounding the town of Paranatinga. Prospecting activities are still present along the Batovi and Jatoba river beds with average reported diamond prices ranging from US$90/ct to US$120/ct for stones ranging up to 2-3 carats in size.
The alluvial diamond production attracted De Beers to the province and an exploration program commenced in 1967 in a joint venture with BRGM of France. The group discovered 39 kimberlites. Shallow drilling was done on a number of pipes (see photo below) and a wash plant was constructed in the north central part of the area about 2km west of the northeast part of current license 867.068/05. None of the discovered kimberlites they tested were significantly diamondiferous.
De Beers also conducted an extensive stream gravel sampling program and likely bulk tested some of the kimberlites as well as some terraces and basal conglomerates. It was reported that some stones were recovered but it is uncertain whether the source rocks were kimberlitic or alluvial.
DeBeers Drill Hole No. PAP07 on an Unnamed Kimberlite Possibly J03, in Central part of Batovi Exploration Area
Small stones have been recovered from at least one kimberlite (e.g. pipe CG01, where 2 stones reported as recovered from 84.82 kg tested, on current license number 867.069/05)
Diamond Indicator Morphologies
Surface textures indicate distance from source
When diamond indicator minerals are eroded from a kimberlite and then transported downstream they are progressively abraded and rounded. By examining the surface texture of a mineral one can estimate the distance of transport. Some types of indicator minerals are softer than others; in particular chrome diopsides (CPX) are very easily abraded and in tropical conditions such as are present in Brazil typically persist for less than a few kilometers from source.
- The Batovi area has historically produced large alluvial diamonds (up to 300 carats)
- Past exploration has not discovered the kimberlite source of these diamonds
- Using Dr. Fipke’s proprietary indicator mineral techniques five potential source areas of the large diamonds have been identified
- A small airborne survey over one of these areas has identified a high priority drill target
CPX diamond indicators are very soft – typically travelling only 3km from source in tropical environments
Notes to map:
1. Altered CPX
The chemically altered and rounded surface show that this grain has travelled ~ 2km from source.
2. Fresh CPX
The absence of alteration and presence of delicate surface features indicate that this grain has not travelled far from source. The composition of this grain is identical to those found inside large (50+ carat) diamonds.
3. Combined Magnetic Anomaly
Directly upstream from the fresh diamond indicators in a combined magnetic (red) and electromagnetic (pink) anomaly.
Diamante have optioned 20 exploration licences in the area and heavy mineral sampling has shown that there are diamondiferous kimberlites in the vicinity.
These heavy mineral samples in areas contain exceptionally high quantitiesof peridotitic and eclogitic garnets, chrome spinels and chrome diopsides with diamond inclusion compositions. The presence and abundance of these minerals support the presence of nearby diamond bearing kimberlites.
Based on the work completed to date there are three high priority areas.