I spoke to Barb Henderson (PFG IR) late last week and got the following information regarding Luicho.
Geological map:
Barb will update the PFG homepage as time permits, with the geological map of the Luicho property, which David Ernst is presenting at the Peruvian Symposium this Friday May 5th. She received a copy of the map on Thursday and is currently compiling the data in the GIS system. She will update the PFG homepage which will provide/present additional details in an overlay format. As example and of interest, she informed me that the detailed map displays areas of overburden in the central area, which explains the surface-sampling pattern in this area.
End of Road construction to the property boundary:
Road construction had been moving well and was one week ahead of schedule until the breakdown of one of the two bulldozers. They therefore have lost approximately one week at the tail end of a steep section nearing the property boundary. The second bulldozer has been working 24 hours and it is expected road construction to the property will complete the first week
of May which is on target with their original prediction.
Access road and drill pad construction will begin immediately thereafter and is expected to take 4-6 weeks. Road cut sampling from blasting will be taken for analysis.
Status of Reverse Circulation drills:
Both drills are being brought in from North America (the Nevada area). The first drill left 3 weeks ago and will be ready for drilling by the end of May. The second RC drill will arrive 10-14 days later as it was in operation at another site in Nevada.
Metallurgical Testing:
Column leach testing is currently in progress. They have been loaded and testing typically runs for 45-60 days. It is expected results will show that a primary crush only will be required, if one is required at all.
Other bulk sampling, for further leach testing is currently being gathered at Luicho and will be brought out on the road. These samples will be used for run of mill testing which essentially means no crushing. Samples may range from 5-10 inches in size.
When crushed, the rock is creating very little fine material. This is a good thing as fine material can clog up the heap leach process, therefore making it less effective.
Discussion regarding carbonaceous rock:
One of the items we have discussed on the thread of late is the carbonaceous mineralization, of which two bulk samples were collected and tested at four crush sizes. Recovery varied in this material from19% to 61%. In our discussion, Barb provided further detail on this.
The first point she made was that, the samples tested were not part of the high grade area. In fact, all bottle roll testing occurred against lower grade samples. Where seen, the carbonaceous mineralization was located in the top 10 meters of sandstone. The carbon is in the shales, of which some has mobilized into the top of the sandstone.
Barb indicated they have been aware that certain areas of Luicho are carbon bearing since early in the project. Early cyanide and fire assay testing was performed against these carbon bearing samples. This testing showed there were different species of carbon, each showing different properties. Where the carbonaceous mineralization was cyanide amenable, results were good and matched favourably against fire assay testing (both methods showed the same). Where the carbonaceous mineralization was not cyanide amenable, cyanide testing showed on average as 80% of fire assay results.
Barb mentioned that it was expected therefore that not all of the carbonaceous mineralization (6%) would show this less than average recovery rate. Instead it is expected that « of the carbonaceous mineralization or 2-3% of the potential mineralization (using the 175m depth potential) may show a less than average recovery rate.
We discussed how carbon bearing mineralization might typically be dealt with in a deposit of this nature. Barb explained how in this case, the carbon and gold are not together. The gold is in open spaces and the carbon is imbedded in the surrounding sandstone.
She explained how bottle roll testing is an attempt to speed up the process of heap leaching by shaking the fluid, but in the case of this carbonaceous mineralization, the results can become skewed. From Barb's explanation, I understood that the rock is crushed to a size which will liberate the gold but not the carbon. The shaking causes the gold to get enriched in the fluid which for the first 80 hours has no effect. After 80 hours the carbon begins to preg-rob the solution, although not strongly (removes gold from the solution). users.wantree.com.au users.wantree.com.au Column leach testing will be much more accurate in determining an accurate recovery rate for this carbonaceous mineralization.
There may be three possible outcomes that could occur:
1) Carbon has no effect. At a certain crush size (example: « - 1") only gold is liberated with a 75-80% recovery rate.
2) Carbon has an effect, processed the same way as the rest of the deposit. Each species of carbon is mapped and then heaped separately, each with different recovery rates. Expected recovery rate is 10-15% less than the norm.
3) Carbonaceous mineralization is not amenable to leaching. Similar to what is done in Nevada deposits, process rock before heap leaching. That is, induce oxidation, roast, autoclave, treat chemically and then heap leach.
For any geos out there, please forgive any errors/omissions on my part.
Discussion regarding Luicho Infrastructure:
I had a brief discussion with Barb regarding the infrastructure at Luicho. She wanted it to be perfectly clear that the infrastructure is far from perfect. This is a very difficult area topographically to work in. Additionally, there is no electricity to the villages and the surrounding areas. While this is a challenging area, the property is excellent and is very positive to designing a pit.
One of the positives of the bottle roll testing is that it is becoming quite clear that an electrical grid will not be required, heap leaching does not require this. What electricity is required, can be generated from the near by river. This would have been one of the bigger areas of concern, but should not be a problem in this case.
Other:
Barb is very amenable to discussing anything related to the infrastructure, metallurgy etc. with any and all of us. Clearly she can speak to an average investor like myself and explain in terms understandable to myself, but if any of the more informed (geologists, newsletter writers etc.), would care to give her a call with any questions, she would be glad to provide this service.
PFG Investor Relations: (604) 689-1976 Toll Free: 1-888-775-7097
Hope this helps,
Qd |
