2001-09-05_REVISION - M1977342

• Permit No: M1977342
• IBM Index Class Name: Revision
• Doc Date: 9/5/2001
• Doc Name: POND 1.2 LINER PROTECTION ISSUES
• From: DMG
• To: HENDERSON MINE
• Type & Sequence: TR8
• Media Type: D
• Archive: No

v
STATE
OF
COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 215
Denier, Colorado 80203
D I v I s I O N o f
Phone: [phone] MINERAL S
FAX: [phone] MEMO TO FILE &
GEOLOGY
0.ECLAMATION
MI NING•SAFETY
Date: September 4, 2001
Bill Owens
Governor
Specialist: Allen Sorenson Signed: DRAFT eregE w,lcner
Executive Ouector
M¢hael B. Lons
Division Deector
Subject/Opera[odOperation/Fil e No. Sludge Disposal in Pond 1.2, Henderson Mine,
Climax Molybdenum Comaanv . Permit No. M-1977-342, Technical Revi sion TR-08
Type of Interaction: Meeting Phone Other
Person(s) contacted and affiliation: Tony Lucero, Environmental Coordinator at
the Henderson Mine. 303/569-3221 ext. 1287
Summary and Resolution of Interaction: Approval of technical revision TR-08 included a condition requiring the
Operator to submit and gain approval of a sludge placement plan thaC would prevent damage to [he Pond 1.2 liner
during sludge deposition operations. Tony Lucero contacted the Division during preparation of the sludge placement
plan and stated that a conveyor system had been selected. I slated at that time that one concern with a conveyor
system would be that any rocks that may become mixed in with the sludge and drop from the end of the belt onto the
liner would damage the liner. Mr. Lucero said that there should be no opportunity for rocks to become mixed with
the sludge, and included the following statement into section 3.2 of the sludge deposition plan submitted 4-20-01:
Since (high density sludge) contains no coarse materials and has a consistency of silty soil, damage [o the
liner by this manner of loading is considered unlikely.
The Division considers the potential for rocks to be inadvertently mixed into the sludge to be unlikely, but could
occur if sludge moving equipment (Crocks and loaders) are used for other earth moving jobs and then not adequately
purged of rocks prior to shifting to a sludge moving task. Rocks would also have the potential to be mixed with the
sludge if the sludge is placed in temporary stockpile (see below) and the stockpile area is not adequately controlled.
Sludge deposition tasks should only be conducted by personnel [hat have been [rained and instructed to prevent rocks
from being introduced into Pond I?.
On 9-4-01 I notified Mr. Lucero (by voice mail) that another concern the Division has with the proposed sludge
deposition protocol is the proposal to route earthmoving and compaction equipment onto the lined area. For example,
the proposal calls for walking the conveyor out onto the previously deposited sludge, with the sludge acting as its own
protective base layer. The proposal also suggests that low ground pressure (LGP) tractors or graders may be used
to work the top of the deposition areas. The plan also calls for the construction of a pump sump on the liner including
a 6-inch layer of a/a inch drain gravel topped by 6 inches of roller compacted select fill. The Division's concern is with
the thickness, grain size, and angularity of fill that must be placed onto the liner in relation to the type of equipment