PERMFILE46723

• Permit No: M1988112
• IBM Index Class Name: Permit File
• Doc Date: 11/8/1988
• Section_Exhibit Name: APPENDIX Q ADEQUACY REVIEW QUESTIONS AND RESPONSES
• Media Type: D
• Archive: No

t 19. The analyses presented in Appendix F indicates that the material was
ground to -10 mesh and thoroughly blended. The textural analyses of
the tailing material presented in Appendix D indicated that
approximately 81Y of the whole tailing were smaller than 200 mesh. The
tailing analyses conducted to determine resulting water quality may
therefore not be representative of the final tailing due to the
variation in particle size. Please address.
Response: The tailings materials used in the tests were actual tailings
' generated from small scale mill processing in Battle Mountain
Gold Company`s Battle Mountain, Nevada laboratory. All materials
for the acidification neutralization potential tests were run
' through either a 10 mesh or 100 mesh sieve to ensure consistency
in test results. The tailings materials were run through the 10
mesh sieve and, as could be expected, all material passed through
the sieve.
Exhibit D, Section D.6.2 revised to discuss sample origin 4/20/89.
20. Was the tailing material processed through the flotation and or the
carbon-in-leach circuit prior to analysis? If so, please describe the
processing methods, chemicals utilized, duration and rinsing methods.
If not, the simulation should be made, with actual expected ore size
' represented, to predict the disposed tailing effluent water Quality.
Response: The sample was representative of the actual material expected on
site after processing through the flotation and carbon-in-leach
circuit. The original sample tested and presented in the permit
application was not dewatered prior to testing since at that time
BMR was planning a traditional tailings impoundment. When BMR
decided to dewater the tailings/concentrates prior to disposal
a new sample which included the dewatering was tested. Test
results for the dewatered sample are now included in Appendix F.
Both samples tested were processed through the same circuit as
described below. The sample was ground to 80% passing 250 microns
in the presence of 0.15 pounds of potassium a;ayl xanthate per ton
of ore. The ground sample was floated for approximately five
minutes using 0.05 pounds of glycol per ton of ore to maintain
a stable froth bed. The flotation tails were filtered. The
flotation concentrate was ground to 80% passing 75 microns. The
concentrate slurry was adjusted to pH 11 with type 3 Portland
cement. Sodium cyanide was added at the rate of 8 pounds oer ton
1 of concentrate. The concentrate was leached fur fo~•ty eight hours
at ambient temperature. The concentrate slurry was filtered and
the filtrate was recovered for analysis. The filter cake was
rinsed with 250 grams of fresh water per 1000 grams of solids.
The washed concentrate solids were recombined with the flotation
tails and packaged for shipment to the SRK laboratory.
Exhibit D Section D.6.2 revised to discuss sample origin 4/20/89.
21. Please discuss what effect the dilute sulfuric acid used in the batch
' tests have on the sulfate concentrations reported in the tailings