Nickel Laterite Exploration
overview
Perilya controls 60 square kilometers of nickel laterite concessions in the Dominican Republic. Two of Perilya's 100%-held concessions, C1 and Corozal, are located immediately adjacent to the Falcondo mining and smelting complex which has a nameplate capacity of approximately 28,000 tonnes of nickel in ferronickel annually.
Perilya's strategy for its nickel laterite concessions is to maximize value to the Company by identifying mineralized material that may be processed economically through existing nickel facilities, or by other processing alternatives, including development of a stand-alone operation. The potential to utilize existing smelting infrastructure may provide Perilya with an advantage compared with similar greenfield, stand-alone nickel laterite projects.
project highlights
- Three concessions, C1, Corozal and Cercadillo, held 100% by Perilya totaling 60 square kilometers (6,000 hectares) over the nickel laterites of the Dominican Republic.
- Indicated mineral resources of 3.0 million tonnes grading 1.49% nickel and Inferred mineral resources of 3.2 million tonnes grading 1.5% nickel at cut-off grades of 1.0% nickel at the Cumpié Hill project located on the C1 Concession. View technical report
- Conceptual mining study for the Cumpié Hill project completed in 2008 and environmental impact assessment study underway and to be completed in 2009.
- Two other projects in the vicinity of Cumpié Hill are Corozal and La Leonora.
- The southernmost concession, Cercadillo, holds potential for saprolitic ridge top in-situ lateritic horizons and also for significant transported limonitic/saprolitic blanket mineralisation
nickel laterite exploration
location and access
Perilya's concessions cover the largest nickel laterite occurrence in the Dominican Republic outside the mining leases held by Falcondo. Perilya's C1 Concession is immediately adjacent to the Falcondo complex. Cumpié Hill is Perilya's most advanced nickel laterite exploration project and is just 7 kilometers from the Falcondo smelter. The Corozal Ridge project is located approximately 3.5 kilometers east of Cumpié Hill and 1.5 kilometers west of the Company's Cerro de Maimón copper/gold operation. The Cercadillo concession is approximately 20 kilometers to the southeast of Cumpié Hill and is located at the southern end of the Dominican nickel laterite belt, of which Perilya controls approximately 44 linear kilometers.
geology of the dominican nickel laterite belt
Nickel laterite deposits in the Dominican Republic are associated with a belt of alpine-type serpentinized ultramafic rocks (peridotites) that extends over a distance of 95 kilometers along the eastern flank of the Cordillera Central. The geological setting of Perilya's concessions is similar to that of Xstrata's Falcondo property and to other nickel laterite deposits, such as Loma de Hierro in Venezuela and Onça Puma in Brazil.
Under the tropical weathering conditions of the Dominican Republic, nickel grades may be enhanced in the laterite which develops over the peridotite. The typical laterite weathering profile here consists of an upper zone of high iron limonite with typical grades of 0.2-1.5% nickel which is underlain by saprolite with typical grades of 1.5-2.0% nickel. The laterite profile over the peridotites in the Dominican Republic is approximately 30 meters thick, with the zone of nickel enrichment ranging from 2 to 20 meters in thickness. A typical cross-section through any of these deposits shows the nickel mineralisation to be thickest on the hilltops and to thin and finally pinch out on the flanks of the hills.
cumpié hill project
Two main areas of nickel laterite development have been identified in the Cumpiê Hill project area, designated as the Cumpié and the Loma Mala sectors.
The Cumpié sector consists of three separated areas of nickel laterite which together cover an area of 33 hectares over a combined strike length of approximately 1,250 meters in a north-south direction and with an average width of 300 meters from west to east. The thickness of the laterite profile ranges from 2 to 40 meters with an average thickness of 20 meters. Limonite, transition, and saprolite horizons are developed at Cumpié, although, generally, the limonite is less well developed and/or preserved than the transitional and saprolite zones. The contact between the laterite profile and the underlying ultramafic peridotite bedrock contact is generally gradational and barren peridotite remnants and boulders are common within the laterite zone.
The Loma Mala sector covers an area of 8.4 hectares over a strike length of approximately 400 meters in a north-south direction and with a maximum width of 400 meters east to west in the northern part, narrowing to around 150 meters in the south. The thickness of the laterite profile ranges from 2 to 20 meters with an average thickness of 13 meters. As at Cumpié, limonite, transition, and saprolite horizons are developed at Loma Mala, and the limonite is less well developed and/or preserved than the transitional and saprolite zones. The contact between laterite and ultramafic bedrock contact is generally transitional and barren rock remnants and boulders are common in the laterite.
Mineral resource estimates were reported in February 2008 for the combined Cumpié and Loma Mala deposits on the Cumpié Hill project at a range of cut-off grades, as shown in the table below:
A preliminary conceptual mining study for the Cumpié Hill deposits was completed by independent consultants in 2008 and an environmental assessment is in preparation by a Dominican Republic environmental consulting company.
| Cumpié Hill Mineral Resource | ||||
| Classification | Cut-Off Grade (% Ni) | Tonnage (million tonnes) | Grade (% Ni) | Contained Ni (thousand tonnes) |
| Indicated | 0.8 | 3.7 | 1.38 | 51 |
| 0.9 | 3.4 | 1.43 | 49 | |
| 1 | 3 | 1.49 | 45 | |
| 1.1 | 2.6 | 1.55 | 41 | |
| 1.2 | 2.3 | 1.61 | 37 | |
| 1.3 | 2 | 1.67 | 33 | |
| 1.4 | 1.7 | 1.72 | 30 | |
| Inferred | 0.8 | 4.1 | 1.3 | 53 |
| 0.9 | 3.7 | 1.4 | 52 | |
| 1 | 3.2 | 1.5 | 48 | |
| 1.1 | 2.7 | 1.5 | 41 | |
| 1.2 | 2.3 | 1.6 | 37 | |
| 1.3 | 2.1 | 1.6 | 34 | |
| 1.4 | 1.7 | 1.7 | 29 | |
other projects
corozal ridge
The Corozal Ridge nickel laterite zone is located approximately 3.5 kilometers east of Cumpié Hill and 1.5 kilometers west of Perilya's Cerro de Maimón copper/gold operation. Perilya first identified nickel laterite at Corozal Ridge from a shallow test pit which averaged 1.8% nickel. In 2008, a 60 hole drilling program was completed. The known area of laterisation extends for more than 500 meters along strike over an average width of 10 meters.
la leonora river area
The La Leonora River area is located to the east of Cumpié Hill and in a flat zone in the lower foothill target zone of the Cumpié massif. Drilling has shown that the limonitic and saprolitic horizons represent both in-situ weathered ultramafic rocks and transported remnants and boulders.
cercadillo concession
The Cercadillo Concession is located at the southern end of Perilya's holdings in the Dominican nickel belt, approximately 40 kilometers southeast of Cumpié.
Mineralisation at Cercadillo occurs on the top, flanks and lower flat zones of an ultramafic ridge. On the ridge top, scout pitting returned 8 meters grading 2.2% nickel and a number of auger holes drilled on the flanks have returned intercepts over 1% nickel.
The current program on the Cercadillo Concession consists of auger drilling following a radial pattern from the ridge tops, downwards along the flanks to the flat lower areas. The scope of the program is to contour the extent of the mineralisation in areas of known saprolite in the flatter zones surrounding the ridges.