2008-12-10_REVISION - C1981010

• Permit No: C1981010
• IBM Index Class Name: Revision
• Doc Date: 12/10/2008
• Doc Name: Trapper G-Pit Landslide Mining Assesment
• From: Agapito Associates Inc
• Type & Sequence: PR6
• Media Type: D
• Archive: No

.Zcrnua?•v 15, 2008 1,11ge 10
3.0 Roc K N'1ASS CIIARAC -FERIZA 1 101
Lithologic logs were recorded for all 19 boreholes. The logging procedures followed
AAI core logging guidelines.`) Data collected for each significant interval were the following.
• Rock type and description.
• Rock Quc&1Y Desi,twlion (ROD) W varies between 0-100 as measured from the length of
intact core pieces greater than 4 inches (10 cm).
• lnlillittq Index (1) varies 1-5 and indicates the type and quantity of infilling in fractures.
A value of5 is unfavorable indicating thick weak clayey infilling.
• Irlimciril'v Index (P) varies 1-5 and indicates the planarity of fractures. A value of 5 is
unfavorable indicating flat fractures with no steps or conchoidal shapes.
• Roughness Index (R) varies 1-5 and indicates the roughness of fractures. A value of 5 is
unfavorable indicating very smooth tracture surfaces.
• Ftwelure Ft-eyuenc'v Index (FF) varies 1--5 and indicates the number of natural fractures
per meter of core run. A value of 5 is unfavorable indicating highly fracture core run
(>5 fracture/ft).
• .Slrucvure ln(lex (FT) varies 1-5 and indicates the predominant type ofof iscontinuity in the
core run. A value of-5 is unfavorable indicating all natural jointing.
• Fracmi-e Dur-cihilily Index (FD) varies 1-5 and indicates the in situ strength of fractures.
A value of5 is untavorable indicating low fracture strengths and triable surfaces.
• Disfurhanee Index (D) varies 0-1 and indicates the amount of mining disturbance that the
rock mass has been exposed to. A value of I is unfavorable indicating highly disturbed
by mining or landslide.
The RMR system' 1.12 was selected because it is based on extensive mining case histories
in low to medium strength rock masses. RMR values are based on five factors: (1) RMR, is a
function of intact I..IC'S rock strength (maximum 15 points), (2) RMR, is a function of ROD
(maximum 20 points). (3) RMR; is a unction of fracture frequency of naturally occuring
jointing (maximum 20 points), (4) RMR, is a function of joint condition of infilling, persistence.
and roughness (maximum 30 points). and (5) RMRS is a function of groundwater condition
(maximum 15 points). The maximum RMR value is 100. RMR values at Trapper Mine are
typically, in the range of 55-75. The RMR; value was always taken as 10 because field
observations of the highwall mining face suggest the rock is normally dry with minor
groundwater seeps, constant flow is rarely observed.
Agapito Associates, Inc. (3000), "Core Logging Procedures." Grand Junction, CO, May.
Qualih Designation (RQD) Index in Practice," Ruck
Deere D.U. and D.W. Deere, (1988), "The Rock
(7a.c.ci?c,rliun .`1°slerns Ji,r Fngineerin,L Purposes, ASTM Special Publication 984, Ed. E_. Kirkaldie, p. 91 101.
Bieniawski Z.I (1989), "Engineering Rock Mass Classifications," Wiley and Sons, I"Limsylvania PA, p. 35 95.
" Bienia%vski Z.T. ( 1993), "Classification of Rock Masses for Engineers: The RMR System and Future Trends,"
C'onyn•ehensire Rock Engineering Principles Practice and Pruiecvs, Ed. J.A. Hudson, Vol. 3, p. 553-573.
Agapito Associates, Inc.