2011-08-08_REVISION - M1977300

• Permit No: M1977300
• IBM Index Class Name: REVISION
• Doc Date: 8/8/2011
• Doc Name: Grouting and Abandonment of Historic Exploration Corehole
• From: Whetstone Associates
• To: Cotter Corp. and DRMS
• Type & Sequence: TR16
• Email Name: DB2
• Media Type: D
• Archive: No

Interval
(ft btoc PVC)
Description
Batch
Bags
Cement
Gallons
Water
:C
Pressure
Incremental
Volume
207 - 217
Bedrock below 2"
steel casing
1
5
75
2:1
80
75
2
3
30
1.5:1
80
105
3
3
30
1.5:1
80
135
4
2
15
1:1
80
150
5
2
15
1:1
80
165
6
2
15
1:1
80
180
8
2
15
1:1
80
195
9
4
20
0.75:1
80
215
10
4
20
0.75:1
80
235
11
4
20
0.75:1
80
255
12
4
20
0.75:1
80
275
100 - 207
2" steel casing and
weathered bedrock
1
3
30
1.5:1
40
30
2
3
30
1.5:1
40
60
3
4
30
1:1
40
90
4
4
30
1:1
40
120
5
4
20
0.75:1
40
140
6
4
20
0.75:1
40
160
7
4
20
0.75:1
40
180
8
4
20
0.75:1
40
200
9
4
15
0.5:1
40
215
Whetstone
Technical Memorandum
The second stage was grouted by setting an inflatable packer in the 2 inch steel casing at 100 feet
btoc PVC and injecting neat cement into the corehole at 40 psi until refusal. The starting grout
mixture had a water -to- cement ratio of 1.5:1 and was gradually thickened to a maximum of 0.5:1.
Grouting for the second stage started at 3:36 pm and reached refusal at 5:01 pm. Upon refusal, the
corehole was shut -in and the pressure was observed for 15 minutes to ensure that the section was
adequately sealed. The total grout take for the corehole and damaged casing between 100 and 207
feet btoc PVC was 215 gallons (Table 2). Completion of the second stage eliminated groundwater
discharge from the corehole.
The remaining annular space in the 2 -inch steel casing above 100 feet was sealed with cement using
a tremie pipe to pump the cement from the bottom of the hole until it overflowed from the PVC
access pipe at the surface.
Table 2. Placed Grout Volumes, Water to Cement Ratios, and Injection Pressures
Intact 2" steel
casing
4
20
0.75:1
0 - 100
20
4109C.110808 5