Jon, some more on the pay streak (venero) subject. This and my last post represent my attempt at a summary on the subject.
One place where I found the spacing between veneros was discussed in the Freydanck report:
"The exploitation of the gold of the river gravels started in the year 1959, when the author advised the cooperatives to leave the old shafts of the Aramayo Company. When the first rich pockets below water level were discovered, all the people moved to the beaches of the river. They drive shafts into the beaches of the river and from their bottom (8-12 m below water level) exploit the gold on the bedrock with drifts. As this area has electric current from a hydroelectric power station, pumps are used to drain the water. The 8-10 m of gravel below water level have several (3 to 4) paystreaks, which sometimes are richer than the concentration on the bedrock. Those are not exploited. Lack of technical direction in all this region results in an inadequate exploitation, even of the concentration on the bedrock".
Keep in mind that this is 8-12m from river level to bedrock. In our mine shaft at Cangalli, it is about 1000 feet down to the old paleochannel on the bedrock. So, there is quite a difference in depth from river to bedrock, depending on where you are in the valley. If you have done your DD, you will know that the old paleochannel and the conglomerate above it is all above the current river, upriver near Unutuluni. You would also know that for most of the valley, the current river is not over the old paleochannel, and sometimes it is not even in conglomerate.
Those veneros near the bedrock are quite close together. As you get higher in the conglomerate, they are less closely spaced. As you may know, in the current mine shaft at Cangalli, they were working the 195 and 237 levels. I think that means meters below surface, which is just somewhat above river level. I do not know if there is a minor venero or two between the levels they are working.
Remember, it depends on what you call a venero.
Take Guido's first report. These are pan concentrate analyses, converted to assay for whole sample. It does not count any contribution of the large and tailings components of the sample. Values of 0.015, 0.038, 0.534, 1.117, 2.030, and 19.107 gcm, with a weighted average of 2.673 gcm on a range of individual samples of 682 to 1296 grams were obtained from the Chaco Front. Note that if the other portions of the sample had been assayed it would result in a total assay maybe three to five times this. Is a venero 2 gcm? 1.1 gcm? Did we get a big venero, two small veneros and three non-veneros in this set? Or two non-veneros and one extra small venero?
It gets more interesting. In the mine shaft itself, samples from the venero levels they were working were: 0.041, 0.097, 0.137, 0.259, 6.135, 6.342, 8.499, 31.109, for an average contribution by the panned concentrate of 6.742 gcm, and a grand total of 19.078 gcm when the large fraction and tailings are added in. So, even going along a venero layer, you might be at the top or just above the top of the venero and get a low assay, but maybe at bottom or near bottom you would get a high assay. Although the stopes are not horizontal, they are in a horizontal direction. So, if you grab samples on surface, you get a variety. If you go horizontally, you get a variety. And, GE and the locals have to know what the assays are for the whole 1000 foot mine shaft, top to bottom. The way I look at it, you have some low grade stuff, and lots of higher grade mini vereros, veneros, and super venero layers to make up the total. The company has sort of been using a range of 0.25 to 0.75 gpt average grade, when projecting gold production. I think they are saving the super veneros as a "surprise". We shall see, this is my opinion only.
The subject of veneros is not simple. To model a given area, like Chaco mountain, would require a whole lot more detail than I have available. But, the company has the information. And, there are certainly glory hole type venero assays that have been reported by others, such as Freydanck, BD, etc. Folks, we are not just near elephant country, we own the elephant country. The way I look at it, we can claim all the samples and production done in the past, if it is documented. If Aramayo handled tons of dirt and produced hundreds of thousands of ounces a year, my opinion is that this represents hundreds and hundreds of thousands of samples that can go into proving reserves in the areas that were sampled or mined. As long as it is documented.
Lets talk about our current production. I would say that each ton is a sample (about one-half a cubic meter). So, we already have over 150,000 samples obtained by production. Aramayo has hundreds of thousands of samples. I read they had 70 mine shafts. Also, the locals have produced thousands of samples. Maybe someone should put a bug in Terry's ear to consider this approach when claiming resources/reserves?
We have samples on surface, samples at depth, all up and down the valley. More than most probably thought. Lots more. I may be wrong, but prior sampling and production records, along with our current production, is going to get us to the proven and probable resources and reserves claims faster than some might have thought.
Just my opinions. Do your own DD and get your own concept of where GE may be headed.
If any of you are tempted to jump on those numbers below 0.1 gcm and say, "that's probably what most of the mountains are", let me provide a comment. Those assays represent only what Guido got by panning. He averaged 95 samples and got 1.499 gcm average, all contributed by the concentrate. He did not assay large stuff and tailings for each the 95 samples, unfortunately. But he did test large stuff and tailings on one set and reported a much larger total assay. Just to remind you of the inaccuracy possibility of using pan concentrate only (like BD and others), the weight of the total concentrates from the 95 samples represented only 3.4% of the total field samples.
Yes, just 3.4%! So, if there is any gold in the 96.6% weight that is not in the concentrate, you have the chance for large errors in determining total sample assays. Particularly since it is well known that the samples contained lots of flour gold (BD's term for micro fines).
gerald |
