History/Exploration
The deposit occurs as a single north-northeast trending iron rich stratigraphic unit that extends over 4 kilometres within the Proterozoic Corella Formation that grades from Haematitic Quartzite through Banded Siliceous Ironstone and Siliceous Ironstone into massive Haematitic Ironstone. The ironstone is generally fine to medium grained with increasing grainsize related to haematite content. Remobilization of haematite with coarse recrystallization is evident in the vicinity of some shears.
Following preliminary drilling in 2007, Cerro has now completed a detailed program of geologic mapping, surface rock-chip sampling and partial drill testing of the Mount Philp Deposit during 2010-2011 to enable resource estimation.
In total, 48 diamond and reverse circulation drill-holes were completed and included in the Resource over a total of 4km of strike. Drilling is located on a nominal 100 metre pattern along the strike length of the ironstone. At this stage of the program the majority of pads at the northern half of the deposit have been drilled with fans of drill holes declined at 0, 30 and 60°. In the southern half of the drilled area the drilling has stepped out to 200 metres with holes at 30 and 60°.
The resource was calculated as the sum of block volumes contained within the zones coded as Haematitic Ironstone and Siliceous Ironstone. Tonnages were calculated by applying the average zone bulk densities to those volumes.
Based on drill density, sampling protocols and grade variography 63% of the total resource fulfils the requirements of an Indicated Resource. This equates to an Indicated resource of 19Mt grading 41% iron and 38% silica and a further 11Mt, in the Inferred category, grading 34% iron and 48% silica.
| Geological Boundary | Category | Tonne Million | Fe% | SiO2 % | P % | AI203 % | TiO2 % | LOI% |
| Haematitic | Indicated | 12.78 | 48.82 | 27.55 | 0.01 | 1.14 | 0.34 | 0.30 |
| Siliceous | Indicated | 6.33 | 26.47 | 58.91 | 0.03 | 1.61 | 0.47 | 0.29 |
| TOTAL/avg | Indicated | 19.11 | 41.42 | 37.93 | 0.02 | 1.30 | 0.38 | 0.29 |
| Haematitic | Inferred | 4.63 | 47.78 | 28.85 | 0.02 | 1.58 | 0.38 | 0.26 |
| Siliceous | Inferred | 6.77 | 24.47 | 60.67 | 0.03 | 2.27 | 0.51 | 0.34 |
| TOTAL/avg | Inferred | 11.40 | 33.82 | 47.74 | 0.02 | 1.99 | 0.46 | 0.31 |
*Mineral resources that are not mineral reserves do not have demonstrated economic viability.
Preliminary metallurgical test work conducted in 2010 on samples from within the inferred resource model, indicated the ability to produce a high grade (68% iron) product using the well proven flotation method to remove silica. The flotation sighter tests on samples of varying silica content indicated that the production of a final iron ore grade product is achievable from high silica content material. This indicates the ability to process all the material within the resource, regardless of silica content, and produce a final iron ore grade product. The flotation sighter test work produced an average 68% iron product at 77% iron recovery and 1.5% silica content (Refer Announcement: 22 December 2010). Further test work is to be conducted to optimise the flotation conditions to maximise iron recovery whilst still maintaining the low silica content in the final product.
| Feed Grade | Flotation Concentrate Grade | Iron Recovery | |||
| Sample | Iron(% Fe) | Silica (%SiO2) | Iron (%Fe) | Silica (%SiO2) |
(%) |
| Zone 1 | 53.9 | 21.6 | 68.0 | 1.5 | 76.9 |
| Zone 2 | 44.8 | 34.4 | 67.7 | 1.5 | 82.6 |
| Zone 3 | 31.8 | 52.9 | 67.5 | 1.5 | 68.6 |
For complete resource summary of rock type and cut-off grade, please refer to Mt Philp Announcement of February 1, 2012
MT PHILP DRILL SUMMARY As at December 31, 2011 (Below)
