Summary:
The Lik deposits are examples of a large group of deposits broadly referred to as sediment-hosted zinc-lead-silver deposits.
The Lik deposit is hosted in the upper part of the Ikalukrok Unit of the Kuna Formation. At Lik, the immediate host rocks are carbonaceous and siliceous black shale, with subordinate black chert and fine-grained limestone. These rocks strike broadly north-south and dip at approximately 25° to 40° to the west. The massive sulphides are overlain conformably by rocks of the Siksikpuk Formation. The sequence is overridden by allochthonous rocks that form high hills north and west of the deposits.
The mineralized sequence was initially interpreted to be cut by several minor faults. Recent drilling and interpretation demonstrated that some of the inferred faults may not exist, or the movement on the fault is minor. The most significant of these faults is the Main Break Fault. While the plunge of the northern end of the Lik deposit increases to approximately 25° to 42°, it is no longer thought that there is a break separating the Lik South and Lik North deposits. It is also unclear whether there is a change in strike north of the fault, or whether the change is more apparent due to topography. Additional drill data will be needed to clarify these relationships.
There is another group of steeper faults that were interpreted to strike northerly or northwesterly with reverse throws of up to 100 m. Interpretation of drilling in 2008 appears to demonstrate that several of these faults may also be non-existent or more minor than previously interpreted.
The Lik deposit is a stratiform zinc-lead-silver deposit. The deposit is continuous outside the Lik property onto the adjacent Su property to the south held by Teck. The southern continuation of the Lik deposit is referred to as the Su deposit.
Within the Lik property, the deposit is divided into two parts. The main part of the deposit within the existing claims is referred to as the Lik South deposit. Previously, the boundary between the Lik South and Lik North deposits was defined by the Main Break Fault. More recent work appears to show that the fault does not exist, or that its displacement is minor. The division into two separate blocks is maintained and the boundary is taken as Section 13800N for this report. As presently interpreted, the largest lens, the A Lens of the Lik South deposit, is approximately 1,100 m long and 600 m wide and much of it is flat-lying. It contains the bulk of the tonnage in the Lik South area. The second largest lens, B Lens, is approximately 500 m long, up to 200 m wide, and averages approximately 120 m wide. The R Lens is approximately 400 m north-south, 100 m east-west, and up to five meters thick and lies about six meters above the A Lens. Mineralization in the Lik South deposits has been tested down dip to a depth of approximately 150 m to 200 m.
The Lik North deposit is approximately 700 m long and 350 m wide. As with the Lik South deposit, mineralization is interpreted as occurring in a number of lenses, with most of the mineralization present in a single lens referred to as the North Lens in this report. The North Lens plunges at about 25° to 42° and has been tested down dip to a depth of about 300 m.
The deposits strike broadly northerly and dip westerly at approximately 25° to 40°. The mineralization comprises stratiform lenses. The mineralogy of the sulphides is simple and is comprised by pyrite, marcasite, sphalerite, and galena, with rare tetrahedrite, bournonite, and boulangerite. Gangue minerals include quartz (as chert), clay minerals, carbonate, and barite. Noranda recognized six different ore types in its logging of drill core (Scherkenbach et al., 1985). Sulphide grain sizes and grades vary between different ore types. Maximum sphalerite grain size is about 100 microns.
Previous work by GCO claimed that sulphides were deposited in four distinct cycles. The cycles were believed to have been developed close to the likely hydrothermal source of the mineralizing fluids. Individual cycles were interpreted as being quite thin near the margins of the deposit with the thickest accumulation in a single cycle noted to date is approximately 13.7 m. This interpretation is not considered valid by either Zazu or RPA. The more recent drilling has shown that fine-grained and coarse-grained sulphides are interbedded. Banding is variably developed. Higher grades occur in different levels of the sulphide lenses. Locally, the sulphides appear to be structurally distorted. At least some of the mineralization is cut by debris flows and is considered primary, while other textures apparent in the core appear to indicate that mineralization is at least partly diagenetic or post- diagenetic.
While brecciated sulphides are common in high-grade areas, they do not form a large percentage of the overall sulphide mass. Individual breccia zones vary in thickness from a few centimetres to a few metres. The origin of the brecciation is not clear, but at least some of it is judged to be primary.