REV96878

• Permit No: M1988112
• IBM Index Class Name: Revision
• Doc Date: 10/23/1995
• Doc Name: TECHNICAL MEMO BACKFILLING THE WEST PIT SAN LUIS SEQUENTIAL BATCH LEACH TESTS OF PINK GNEISS
• From: MARK J LOGSDON
• To: JIM DILLIE
• Type & Sequence: TR18
• Media Type: D
• Archive: No

BMRI -San Luis Pit Ball: Sequential Batch Tests of Gneiss
The complete laboratory and analytical reports are attached as Appendix A.
The results of the batch leach tests for key parameters are presented in Tables 4-6 as a
function of water :rock ratio (as a surrogate for time and distance from a "source" in
the interstices of the backfill after re-saturation). Tables 4-5 illusvate the results for all
six samples at a 1 to 1 (water :rock) ratio; Tables 6 illusvate the vends for samples
6,4 and 2, the selected as having the maximum, minimum, and median comcenvation of
Total Sulfur. In each table, the "head" analysis of the ground water sample is also
presented for reference.
Table 4: Acid-Base Accounting and General Aqueous Parameters
at Step Al (1:1 Ratio of Water :Rock)
Sample S(t)
(~) S(py)
(%) ANP
crcaco~n~ ANP/AGP
roaaea o. s(pr) pH
(a.) Eh
(mv) Cond
(s) Alk
(rttg/I
CeC03)
Ground na u) na na na 8.20 nd (z) 572 186
water
Test 1 0.49 0.22 1.1 0.16 8.28 [phone]
Test 2 0.62 0.34 10.9 1.03 8.26 [phone]
Test 3 1.33 1.10 0.3 0.01 8.20 [phone]
Test 4 0.42 0.11 5.2 1.53 8.34 [phone]
Test 5 0.55 0.13 45.9 11.20 8.33 [phone]
Test 6 5.01 2.14 2.9 0.04 8.25 [phone]
(1)'na- :not applicable
(z) 'td- :not determineA (in sim Eh unknown; sample samraled m Lxl in truism, but de~aired with NI in tests)
Table 5: Key Acid-Base Accounting and Aqueous Parameters at Step Al
(1:1 Water :Rock Ratio)
Sample S(t)
(%) ANP/AGP
(based on
S(PY) HC03
(mg/p S04
(mg/0 As
(mg/I) Cd
(mg/q Cu
(mg/1) a
(mg/p Mn
(mg/q Zn
(mg/q
Ground na (1) na 226 111 <0.005 <0.005 0.02 <0.03 0.71 0.01
water
Test 1 0.49 0.16 231 134 <0.005 <0.005 0.03 <0.03 1.03 <0.01
Test 2 0.62 1.03 206 111 0.010 <0.005 0.02 <0.03 0.62 <0.01
Test 3 1.33 0.01 210 138 <0.005 <0.005 0.04 00.03 1.70 <0.01
Tesl4 0.42 1.53 177 121 <0.005 <0.005 <0.01 <0.03 0.44 <0.0]
Test 5 0.55 11.20 198 122 0.007 <0.005 0.03 <0.03 0.24 <0.01
Test fi 5.01 0.04 141 150 <0.005 <0.005 0.03 <0.03 1.59 <0.01
(q 'm' : ml applicable
Geochimica, Inc 4 95021/2bSep-95