Open File Report 1976-30

Open File Report 1976-30

OFR 1976-30

Evaluation of Drill-Core Exploration of Sluice Site No. 1, Chipewyan Red Granite Building Stone Project

Author(s) Godfrey, J.D. Date 1976-02-03

After the initial field exploration program in 1972 a potential building stone site was hydraulically sluiced off to aid detailed mapping, sampling and evaluation (Godfrey 1971, 1972). Sluice site number one was drilled during June and July, 1975 in 6 x 25-foot deep holes to test for the depth extension of good quality granite building stone.

The objective of the drilling was to obtain continuous core (i.e. 100 percent recovery) in order to be able to evaluate fracture quality and frequency as well as rock texture, color, and structural-mineralogical characteristics. Prior to detailed study and core logging, the core was thoroughly scrubbed, cleaned and clear shellacked to provide the best possible conditions for viewing and data gathering.

As the core was not scribed during drilling, to indicate its orientation in the ground, and since one objective of the drill core program was to reconstruct a three-dimensional model of the granite characteristics at the drill site, it was necessary to:

1. Carefully orient individual pieces of the broken core for each drill hole by matching across the fracture breaks, and marking a reference line so as to eliminate rotation of the core. This objective was achieved with a high level of confidence in over 90 percent of the cases.

2. Prepare a detailed map of the granite foliation at the drill site and use this data to orient the foliation in each drill core at the appropriate azimuth. The somewhat massive to poorly defined foliation in the core provides the possibility of a small error being introduced in determining the absolute core orientation.

The results of the core study are shown in log form and included as Appendix I. Two cross-sections have been drawn through two N-S lines of three drill holes each, in an attempt at correlation of both rock character and fracture pattern between drill hole data.