GTSM at Nantou County, Taiwan
Tsung Sing (TSUN)
Working conditions during the installation of TSUN were excellent. The site is behind the staff accommodation building at a local school. The area is partially covered and concrete everywhere.
The location of the hole is within 2m of the concrete wall, which on the opposite side, drops off around 5—10m, onto a steep sloping hill. It could be estimated that the hill is perhaps 50—70m above the valley region, which would put the actual instrument depth not far below the valley floor region.
Location of sites in steep topography is often necessary, but comes with compromise of the general ground noise level in the data.
Problems were experienced at this hole as a result of burred edges of the casing in the hole. There were 2 different locations where the baler and test bar repeatedly became caught. Since the locations of these abnormalities had been established many times in the test runs, during the deployment we were able to ease the instrument through with minimal fuss.
There was one major issue during the deployment of the cement at this site. The rig that was used to lower the baler was aging and during the process of releasing the cement the baler was jerked upwards rapidly. This caused a fluid lock with the cement and the baler became stuck. The baler was re-lowered and “very” slowly lifted back out. After some effort and patience, the baler released and we were able to bring the baler back to the surface.
The first target site in this hole was thus abandoned. The deployment was postponed till the discarded dump load had set. A second target was chosen further up the hole at 197.5 m, and the deployment went ahead next day.
This picture shows the view down to the valley floor. In winter these sites get quite cold, there have been reports of snow in this region in past years.