REP35589

• Permit No: M1977215
• IBM Index Class Name: Report
• Doc Date: 4/14/1997
• Doc Name: EVALUATION OF UPPER & LOWER TAILINGS PONDS AT BULLDOG MINE
• Media Type: D
• Archive: No

Bulldog Mine Tai(inRS Ponds Evaluation
3.0 FIELD INVESTIGATIONS
• The initial and subsequent supplemental field investigations were performed between July 26 and
28, 1996 and on September 16 and 17, 1996, respectively. The initial field investigation
consisted of drilling, logging, sampling, and collecting tailings samples of three test holes in the
Lower Tailings Pond and two test holes in the Upper Tailings Pond. The supplemental field
investigation included measuring oxygen profile and oxygen consumption rates in the near-
surface tailings, obtaining additional tailings and soil samples from the Upper and Lower
Tailings Ponds, and collecting tailings pore water samples from [he Upper Tailings Pond for
laboratory metals attenuation testing. The approximate sampling and test site locations in the
Upper and Lower Tailings Ponds are shown on Figures 3.1 and 3.2 respectively.
3.1 Initial Investigations
Test holes were drilled using 3.25-inch I.D. hollow stem augers powered by a CME-7~ drilling
rig. Individual logs of each test hole aze included in Appendix A of this report. All test holes
were backfilled with tailings and a surface plug of bentonite approximately two feet thick was
installed upon completion of drilling and sampling.
Hollow stem auger core (dry core) sampling was conducted with a 2-inch nominal I.D. sampler
mounted in the bottom of the hollow stem auger. Samples were typically collected by augering
2.~-foot nominal length core runs with a steel split barrel liner. Samples from the split barrel
liner were collected by continuously splitting samples along their axial length, discarding the
upper half of the sample, and retaining the lower half in double plastic bags with re-sealable tops
and labeled with a permanent mazker. At selected intervals, 2.5-foot long cleaz acrylic tube
liners were used instead of the steel split barrel liners. The acrylic liners provided samples in a
less disturbed state than were obtainable using a split barrel liner. These samples were left in the
tube, the ends were capped with plastic end caps, sealed with tape, and then labeled.
Relatively undisturbed samples were obtained at selected intervals by slowly pushing 2.5-inch
nominal I.D. thin-walled Shelby tube samplers into the tailings using the hydraulic ram of the
. auger drilling rig. The Shelby tube samples were collected in accordance with procedures
recommended in ASTM D1587, where applicable. After sample collection, the void space
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