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Sirocco's Qualified Person pursuant to NI-43-101 is Mr. Ron F. Hochstein, P. Eng., MBA. Mr. Hochstein is a Director of the Company.
Aguas Blancas
Assay methods are extracted from the Aguas Blancas NI 43-101 Technical Report dated December, 2010.
Each bagged sample (approximately 10kg) from the reverse circulation, equivalent to 0.5m of drilling, is sent to the sample preparation facility at Aguas Blancas. Here the following steps are completed:- All the sample is passed through a jaw crusher, to reduce it to less than 1/4inch.
- Crushed sample is then homogenised and quartered, using a riffle. ¾ of the original
sample is rejected, leaving approximately 500g, which is then dried.
- The sample is then passed through a roll crusher, sized at 2mm. A granulometry check is
made to ensure 90% is passing #10 mesh (2mm).
- The sample is now ground in a ring mill, and a granulometry check is made to ensure
95% passes through a #100 mesh (150um) screen. Any oversize is reground, until at
least 95% has passed through the screen.
- This final ground sample is then quartered, yielding potentially 4 samples (of
approximately 150g each). One is always sent to the Sirocco lab. One is also retained
as a record sample by Sirocco. The other 2 samples are periodically used for check
sampling purposes (this is done for all samples within 1 out of 20 drillholes). One check
sample is sent for external analysis (University of Antofagasta), and the other is submitted
to the Sirocco laboratory with a different sample number.
Prior to May, 2005 most of the Sirocco samples were sent to the laboratory of the University of Antofagasta. The university commonly used Serquim, Antofagasta-based small laboratory, for sample preparation. AMEX visited Serquim in March 2005 and confirmed that there preparation standards were acceptable.
Since July 2005, samples have been prepared and subsequently analysed on site in the new laboratory facilities. Sulphates and nitrates have similarly been analysed in the on-site laboratory, using volumetric techniques, since November 2005. Since April 2006, sulphates have been analysed using ICP equipment (inductively coupled plasma optimal emission spectroscopy), and nitrates using Molecular Absorption (MA) Equipment.
ISO9001 certification has also been obtained, which includes the new on-site laboratory facilities. For iodine measurement, the method used is very similar to that used in external laboratories. The main methods of assay measurement are summarised below:
Iodine
10g sample, leached with hot water and then filtered. Acid and chlorine added to the filtered solution. Heat applied on heating plate, then cooled. Starch added and then titration with sodium thiosulphate.
Sulphates
5g sample, leached with hot water, filtered. 2ml fraction taken, 1ml of acid added 1ml of standard Yttrium, before taking ICP reading.
Nitrates
5g sample, leached with hot water and filtered to 250ml. Solution out into quartz cell and then reading taken with MA instrument. When the on-site laboratory was being commissioned, a set of 20 check samples (CS) were made with respect to iodine measurements, and sent to 3 different external labs. These results are discussed in more detail in Section 14. For the iodine measurements, the sodium thiosulphate is checked every day, with a standard of potassium iodate (KIO3) - standard sample (SS).
For the nitrate and sulphate measurements using the ICP and Molecular Absorption
Equipment, the following QA/QC steps are taken:- Blank sample (pulp blank - PB).
- Internationally certified standards (sulphur and calcium) (standard sample -SS).
- An on-site registered brine standard (SS).
- For ICP, every sample is also finally mixed with pure Yttrium for an additional analysis (SS).
The on-site laboratory is also used for iodine analysis in brine, spent-brine and other aqueous solutions.
It is the author's opinion that the sample preparation and analytical procedures used by Sirocco are adequate for resource and reserve estimation purposes. Key aspects of their QA/QC practice includes:- Compilation of a QA/QC report every 3 months, collating all the relevant data for this time period.
- Routine granulometry checks in the sample preparation shop.
- Updating and implementation of the sample preparation protocol, including all the steps
noted above.
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