43-101 2007 Technical Report On The San Antonio Project, Baja ...

Derry, Michener, Booth & Wahl Consultants Ltd. Page 4416.0 MINERAL PROCESSING & METALLURGICAL TESTINGMetallurgical test work was carried out on Las Colinas by D. R. Shaw of the Colorado MineralsResearch Institute, (CMRI, 1997). Two composite samples of RC drill cuttings, grading 1.07 and1.6 g/t Au respectively, were found to contain pyrite with minor pyrrhotite, arsenopyrite andother sulphides, along with very fine-grained gold. In that study gold bottle leach recoveries offour composites varied from 48.2% to 62.6% and it is reported by Pitalla that these entirelysulphide samples with minor oxidation; they were taken from Holes SA 96-91and SA 96-102,and from depths of 120-160 m. CMRI concluded that “the incomplete gold dissolutions in thesetests reflected the relatively coarse particle size of the as-received cuttings materials”. “Sodiumcyanide consumptions were reasonable at approximately 1 kg/t, as were lime requirements,which were approximately 3 to 4 kg/t.”CMRI reported that “fine grinding would be required to achieve high gold recoveries” and that“core samples would be the most reliable material for future work especially in respect ofconfirming the grinding and liberation requirements”.The samples responded well to flotation and cyanidation of the reground concentrate indicated98% to 99% recovery of the gold. Sodium cyanide consumption was high at 2.7 to 2.8 kg/t of orebecause of the presence of copper sulphides and pyrrhotite in the concentrate. Further testing wasrecommended.Following DMBW’s recommendation in 2007, Pediment has recently sent nine compositedsamples from reverse-circulation drilling samples to SGS Minerals Services in Durango, Mexico.The composites were chosen to represent high, medium and low grade for each of the ore zonesat Planes: oxide, mixed oxide-sulphide and sulphide.A total of 44 samples were sent for oxide, 32 for mixed and 23 for sulphide. Results are not yetavailable.For subsequent metallurgical and scoping studies bottle roll tests should be done using whole(metallurgical) core. (See Section 20)