Introduction
The Wa Project is situated in NW Ghana near the border with Burkina Faso and consists of the Wa Reconnaissance Licence and the Julie West Prospecting Licence application. Castle has an option to acquire a 100% interest in the project from Newmont Ghana Gold Limited. The 0.3Moz Julie gold deposit is located within an excised portion of the Wa Project. Azumah Resources 0.5Moz Kunche gold deposit is located 50km north.
The 8,200 km² Wa project was acquired from Newmont Ghana Gold Limited (NGGL) in November 2007. An extensive sampling and mapping program was undertaken in February and March 2008 with 2,269 samples collected from a variety of areas.
A JORC Code compliant Resource Estimate of 56,000 ounce for the Julie West deposit has been estimated.
Exploration Results
Quartz outcrop at the Wa Project
Quartz vein outcrop at Julie West
Julie West Prospect - Quickbird Image December 2008
Castle has identified a large number of gold in soil anomalies including a strongly anomalous 2,000m long x 1000m wide area west of Crew Gold's 300,000 ounce Julie gold deposit.
This area has reported values up to 3,096 ppb gold (3.09g/t gold) and is hosted by sedimentary rocks flanked by granites to the north and south. In 2008 rock chip sampling defined a high-grade zone of quartz vein hosted gold mineralisation over 500m long.
Nine rock chip samples collected from quartz vein material exposed in shallow workings along a 500m zone averaged 22.2g/t gold. This mineralised area is hosted within a discrete granite body bounded by sediments to the north and south.
The zone of quartz veining is interpreted as being along the same structure as the neighbouring Julie gold deposit (5km to the east). The Julie deposit is an east-west trending zone with shear-hosted gold mineralisation occurring along a granite/basalt contact. Crew Gold (CRU:TSX) has reported an unclassified (inferred) resource of approximately 3.3 million tonnes for the top 30m of the Julie target, containing about 300,000 oz gold.
Seventy eight rock chip samples were collected as part of a program of mapping and field checking of the significant gold in soil anomaly returned from Castle's earlier program of geochemical sampling.
Rock chip sampling has defined the Julie West gold prospect which is an outcropping laminated pyritic quartz vein approximately 500m long. Forty four rock chip samples of the laminated quartz vein have reported an average grade of 13.2g/t gold.
Two phases of reverse circulation drilling in November 2008 and February 2009 at the Julie West prospect have confirmed the presence of an open ended high grade quartz reef that outcrops for over 500m. High grade gold mineralisation was intersected up to 85m down dip.
Julie West Significant RC Results
- 5m @ 28.50 g/t gold (JWRC01)
- 2m @ 41.70 g/t gold (JWRC02)
- 3m @ 13.02 g/t gold (JWRC 03)
- 2m @ 14.40 g/t gold (JWRC 07)
- 3m @ 10.30 g/t gold (JWRC 08)
- 2m @ 13.70 g/t gold (JWRC 10)
- 2m @ 14.87 g/t gold (JWRC 14)
- 7m @ 23.63 g/t gold (JWRC 26)
- 3m @ 10.90 g/t gold (JWRC 27)
- 2m @ 15.59 g/t gold (JWRC 28)
- 3m @ 14.36 g/t gold (JWRC 29)
- 2m @ 17.15 g/t gold (JWRC 31)
- 3m @ 14.19 g/t gold (JWRC 32)
- 2m @ 19.21 g/t gold (JWRC 50)
- 2m @ 12.07 g/t gold (JWRC 53)
- 2m @ 17.55 g/t gold (JWRC 54)
- 2m @ 11.07 g/t gold (JWRC 56)
- 3m @ 9.94 g/t gold (JWRC 57)
Runge Limited (Perth) undertook an independent resource estimate in April 2009 and estimated a total Indicated and Inferred Mineral Resource of 56,000 ounces.
Rockchip sampling along an outcropping quartz vein 1.4km south of the main Julie West vein reported surface grades up to 30 g/t gold. Five RC holes were drilled over two areas in February 2009 along this 1500m long vein with significant results including:
- 1m @ 7.47 g/t gold from 12m (JWRC 67)
- 5m @ 5.12 g/t gold from 5m (JWRC 68)
- 3m @ 2.33 g/t gold from 1m (JWRC 65)
- 4m @ 1.48 g/t gold from 4m (JWRC 69)
This successful first pass drill test provides excellent potential for more high grade gold mineralisation. At surface the vein is laminated and weakly pyritic and extends for at least 1500m. More extensive drill testing is a priority for this target and drilling is planned to recommence in April.
Resource
| Material Type | Indicated | Inferred | Total | ||||||
|---|---|---|---|---|---|---|---|---|---|
| Tonnes (t) | Au (g/t) | Au (ounces) | Tonnes (t) | Au (g/t) | Au (ounces) | Tonnes (t) | Au (g/t) | Au (ounces) | |
| Oxide | |||||||||
| Transitional | 66,700 | 3.8 | 8,200 | 3,500 | 7.8 | 900 | 70,200 | 4.0 | 9,000 |
| Fresh | 316,200 | 4.3 | 43,900 | 28,400 | 3.5 | 3,200 | 344,600 | 4.3 | 47,100 |
| Total | 382,900 | 4.2 | 52,100 | 31,800 | 4.0 | 4,100 | 414,700 | 4.2 | 56,200 |
The resource estimate was completed using the following parameters:
- The resource has a 560m strike extent from 19,660mN to 20,220mN. The vertical extent of the resource is 100m from surface at 280mRL to 180mRL.
- Of the 64 RC drill holes in the database, 61 were used in the resource estimate for a total of 2,662m of drilling. Drilling density varied from 20m by 20m to 40m by 40m over the deposit. All drill holes are orientated at 50° to the west (local grid).
- The RC sampling procedures were reviewed by Runge and are considered to be of industry standard.
- Analytical samples were collected at 1m intervals via a riffle splitter at the time of drilling and then stored off site. Five metre 'spear' composites were also collected and were submitted to the laboratory. If the 5m composite returned an assay greater than 0.1g/t Au, the individual 1m samples in the interval were assayed. The exception was the logged quartz vein, where the original riffle split 1m sample was sent directly to the laboratory.
- A site visit was undertaken by Runge in March 2009.
- Samples were sent to Transworld Laboratory in Tarkwa, Ghana for analysis. Samples were prepared by drying, crushing to -6mm and then pulverising to <75 microns (-200 mesh). Analysis for Au was by 50g Fire Assay with an atomic absorption spectrometry (AAS) finish.
- Quality control samples were collected on a regular basis. The results have been reviewed by Runge and are considered satisfactory.
- Drillhole collars have been surveyed by Coffey Mining (Coffey) using a Sokkia Stratus DGPS to an accuracy of 10mm.
- Down hole surveys were not completed during the phase one drill program (JWRC001 to JWRC021) as the average drill depth was less than 25m. Holes drilled deeper than 50m on the second phase program were down hole surveyed using a single shot Eastman camera.
- Wireframes were constructed using cross sectional interpretations based on a nominal 0.5g/t Au cut-off grade and the percentage of observed quartz. Interpretations were based on those supplied in hardcopy form by Castle.
- Samples within the wireframes were composited to even 1.0m intervals. A 40g/t Au high grade cut was determined by statistical analysis and applied to the 1m composite values.
- A Surpac block model was used for the estimate with a block size of 10m NS by 5m EW by 5m vertical with sub-cells of 5m by 0.625m by 0.625m.
- Ordinary Kriging (OK) interpolation was used to estimate the Julie West Resource. Au has a high nugget effect of 55%. Grade interpolations used search ellipses which were orientated along the object orientations with isotropic search radii in the semi and minor directions. Three passes were used to fill the models with 96% of the blocks being filled in the first two passes. A first pass radius of 60m was used with a second pass radius of 80m. A minimum of 8 samples and maximum of 40 were required for the first two passes. Minimum sample numbers were reduced to 4 for the third pass. The smaller three objects required a minimum of 4 samples for the first two passes and 2 samples for the third, due to the lack of samples within the wireframes.
- An ID² interpolation was also run to compare the OK estimated result. The models compare favourably with the ID² estimate reporting 7,000t more than the OK model at a slightly lower grade of 4.1g/t resulting in 800 less reported ounces.
- No bulk density test work has been completed. A bulk density of 2.4 t/m³ was assigned to the quartz vein within the transitional material and 2.65 t/m³ assigned to the fresh material. These values were supplied by CDT and are considered reasonable for this style of mineralisation.
- The portion of the resource within the primary mineralised vein and defined by 20m by 20m and 40m by 40m spaced drilling has been classified as Indicated Mineral Resource due to the demonstrated continuity of the mineralisation. The depth extensions of the main vein (predominantly more than 20m past the last drill hole), and all three minor veins, have been classified as Inferred Mineral Resource.
Updated May 2009