 |
 |
Sorry Steve (and all), I know that CSM is vital to the assessment. Made ground in that area was brown to black ashy sandy GRAVEL (0-1m), firm grey gravelly reworked clay (1-1.4m), loose black gravelly ashy SAND (1.4-2m), then Natural sand (2m to 2.5m), overlying Firm red-brown CLAY (2.5m-8m). So no obvious source. The well in question was screened 1.5-2.5mbgl (i.e. Across MG sand and natural sand). Possible pathway into monitoring well was along sands as they were being confined by clay layer above in that area. The made ground was pretty much same over that area. Other areas were also quite ashy but less gravelly in top metre, also often didn't have clay "confining layer" between 1-1.4m. The 18% CO2 reading was 3rd monitoring event (out of 4), flow rate of 0.1. Other results were: 1st monitoring event (7%), 2nd (11%), 3rd (18%), 4th (6%) Regards Gareth