Figure 1: Blina Diamond Project, Tenements, Terrace 5 Alluvials and Lamproite Pipes 1.0 Introduction
Central to the Blina Diamond Project is a diamondiferous palaeo-channel, discovered in 1995 and named Terrace 5 (Figure 1). This channel has been tracked over a distance of some 40km and drains the central section of the diamondiferous Ellendale lamproite field. Gravels from this system are characterised by containing significant concentrations of relatively large diamonds2. It is likely that there are multiple lamproitic sources for these diamonds that remain to be identified. Figure 2: Terrace 5 Stratigraphy Terrace 5 was once a major alluvial system with channel widths from 200-500m. Gravels (where present) are variable, but average about one metre in thickness. Diamonds recovered from the gravels are considered large, with an average stone size of around 0.42 carats. Most stones are of gem quality. The largest diamond recovered to date from Terrace 5 weighed 8.44 carats (from Pit 82)6, with stones larger than two carats common.1 2.1 Terrace 5 Bulk Sampling Program 2005 Any of the following which is italicised is taken from statutoryreports as referenced.
During 2005, two large cuts were excavated from within Terrace 5 (Cut 1 and Cut 2) as part of a program aimed at recovering sufficient diamonds to provide a 'run-of-mine' valuation for the Terrace 5 production. The cuts were excavated across the palaeo-channel at two locations (Figure 1). The Government Mines Department decided the bulk sampling operations be considered "trial mining"6.
2.3 Bulk Sampling Test Results from Cut 1 and Cut 2
* Diamonds to 1.5-16mm range recovered for these samples
Figure 3: Bulk sampling Results Cut 1 & Cut 2 (Plan Views) Figure 4: Cut 1 Geology Section View (Overlying Bulk sampling Block Number) Figure 5: Cut 2 Geology Section View (Overlying Bulk sampling Block Number) 3.0 Further Exploration Targets
4.1 Ellendale Diamond Purchase