REV11019

• Permit No: M1974004
• IBM Index Class Name: Revision
• Doc Date: 1/14/1994
• Doc Name: QUARRY WALL STABILITY TR -001 MOBILE PREMIX SPECIFICATION AGGREGATE QUARRY FN M-77-004
• From: DMG
• To: BILL YORKFEIRN
• Type & Sequence: TR1
• Media Type: D
• Archive: No

•
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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Departrtmm of Natural Resources
1 ] 13 Sherman St ,Room 215
Denver, CO 80203
Phone: [phone]
FAX: [phone]
DATE: January 14, 1994
TO: Bill York-Feirn
FROM: Allen Sorenson ~~
OF
~~
~~
~ /~46 ~
Roy Romer
Governor
Michael R. Long
Division Director
RE: Quarry Wall Stability, Technical Revision TR-001, Mobile
Fremix, Specification Aggregate quarry, File No. M-77-004
Please refer to the attached sketch for an illustration defining
the nomenclature used in this memorandum.
Information contained in both the 1981 and 1994 report:3 prepared
for Mobile Premix by Robert Merrill give general operating
parameters related to slope stability at the Spec-Ag Qu<Irry. The
operator should commit to specific pit wall parameters e77forceable
by the Division. Based on review of the Merrill reports, the
following parameters would currently be appropriate:
Quarry Wall West North South
Controlling N-S strike E-W strike E-W strike
Structure 60° E dip 45° S dip 65° N d.ip
Max. Bench 40 feet 40 feet 40 feet.
Height
Min. Catch 15 feet 15 feet 15 feet
Bench width
Max. Bench- 60 degrees 45 degrees 65 degrees
Face Angle
In the portion of TR-001 signed by John Hickman, it is ste-ted that
Mobile Premix has made "close observations at the quarry of the
variations in rock types, joints, and fractures associated with a
metamorphic rock of this type". Since this type of continual
observation of the structural geology of the pit walls is critical
to ensure pit wall stability, the Division will require the
operator to create a separate section in each annual reclamation
report that will include data and narrative to disseminate
information gathered through observations and measurements. related
to structural geology in the pit walls. Mobile Premi:c should
undertake a mapping program at least annually to mea::ure the
orientation, character (roughness, openness, in-filling),