In the case of Chabuca, it is an existing mining operation. The gold taken from the primitive sluice system, and the samples taken of those concentrates, are surely proven. It is happening right now, today and every day. Also, the sampling done on the five mountains of alluvial gold, basically surface sampling, would give additional proven reserves.
Based on that, the Probable reserves would take into consideration the fact that the five mountains are actually an old river bed, and the gold was originally a placer deposit over three million years ago. Placer (river) gold is richer the deeper it is. Hence, the Probable reserves can be determined from the surface sampling and extending into the mountain to a depth of 5 meters or so.
For purposes of this study, the bulk of the reserve calculations are Measured Reserves. We were able to determine the size of the five mountains. The sampling done was extensive, although superficial, and using the formula above, we were able to determine the “measured” reserve value of this mine. On the following pages we are considering the five mountains individually.
While we are talking about “five” mountains, actually they are all connected, and all part of the same ancient river. When the Andes Mountains here formed, in the terciary geological period (over 3 million years ago), the ancient rivers were raised up, and today are in a line. The first page following is the mountainous zones.
The Reserve Zone that covers the entire Chabuca Mine is approximately 5,200 meters in length, with an average width of 1,200 meters. The depth, from the top of the mountains to the valley floor is 170 meters. The area covered would be 6,240,000 square meters.. The depth of 170 meters would then create a block zone of 1,060,800,000 cubic meters. Considering the slope from ground level upward to a mine crest would be roughly one half the volume, the final volume is: 530,400,000 cubic meters of gold bearing material.
This figure, using the formula in the diagram to the right, the actual volume in cubic meters would be 530,400,000 m3 The next step is to convert cubic meters into tons metric. In converting material to tons metric, that can vary widely from 1.4 to 2.8, depending on the weight and specific gravity of the material. The mountains in the Chabuca alluvial gold areas are mostly rock, sands, some magnetite, very little earths.
Thus the conservative figure of 1.8 was selected, while the actual conversion would be closer to 2.3 – 2.4. Thus the tons metric volume would approximate: 954,720,000 Tons Metric The average richness of samples taken at random, although high-grade concentrate samples are not considered.: The average value of those samples would be 1.0139 ounces of gold per ton metric.
That amount, times the metric tons would give us an Inferred Reserve of 967,990,608 ounces of gold in the Chabuca Mine. Using the Geologic Society of South Africa (GSSA) standards,. PROVEN, PROBABLE, POSSIBLE, MEASURED, INFERRED, this reserve would fall into the categories of INFERRED.
The gold zones have not been drilled and therefore, the other categories are not permitted. The total value of the reserves would therefore be over a trillion dollars. As indicated above there are five smaller zones contained within the property.
These are called Mountain Zones and are individually examined below. It should be noted that while the lowest classification, Inferred Reserves, is being used for the total mine reserves, actually the interior of the mountains is fully exposed (see photos) and samples taken would be indicative of the gold content of each mountain examined. Therefore, a classification of PROBABLE can reasonably be used for the Mountain zones.