Document 44rDrO0Bko36Lwnvm2Y1Y8wBG
A p ril 6, 1984 G. D, Lessner Mai! Code 240A W illow Creek Mine and Greenhorn Claims hiadison County, Montana' A fte r review o f geologic and mine planning evaluation work done by the E xplora tion Department and the Mines Department from 1979 through March 1984, i t is my opinion th a t these p ro pe rties are not v ia b le and do not warrant fu rth e r work. As shown by the attached re p o rts , the W illow Creek pro pe rty lacks s u ffic ie n t q u a n titie s o f high-brightness ta lc th a t may be extracte d econom ically, t a lc 3nd c h lo r ite are in tim a te ly mixed to some degree, s trip p in g ra tio s are unfavorable, tre m o lite 1s present in the carbonate zone, and the apparent, lack o f other valuable minerals categorize th is property as one in which Cyprus has no fu rth e r in te re s t. The attached re p o rt on the adjacent Greenhorn claims suranarizes an eva lu ation in which very l i t t l e t a lc was encountered, tre m o lite was again pre sen t, and no oth er valuable minerals were detected. I t is my recommendation th a t the leases on these p ro p e rtie s be terminated,
/h ). H. M. Marian Mail Code 259A HMH/bbi Attachment
PLAINTIFFS EXHIBIT
CAM-27
CPC-BCALTRSCPT00000892
vmXOWCREEKMINEEVALUATION- 1994
An 1n-depth study o f the W illow Creek Mine has been conducted t o deter mine I t s v i a b i l i t y . T h is study addresses (1) the c r it e r ia o f 1381 which led to the de cisio n to not reopen the mine, (2) the v i a b i l i t y o f the mine based on to d a y's economics and (3) the presence o f tre m o lite w ith in th e ore body. This re p o rt Is based on data derived from a continuous and thorough examination o f the W illow Creek Mine which has been c a rrie d c u t by Cyprus In d u s tria l M inerals Company a t costs estimated a t about $100,000 since ta kin g c o n tro l o f the mine.
In 1980, whan eva lu a tio n o f geologic and d r i l l hole data began, the ere reserve c r it e r i a was 500,000 tons of high brightness {+85 GEB) o re . Reserve c a lc u la tio n s made during th is i n i t i a l study Indicated th a t approxim ately 38,000 tons o f +35 6EB t a lc were present, thus the h a lfmi 11Io n -to n c r it e r i a was not met. No fu r th e r studies by the E xplora tion Department were f e l t necessary s t t h is tim e . Since the i n i t i a l study, reserve c r it e r i a .have changed and sm aller deposits are being considered. This change, coupled w ith a need to document the re s u lts of the 1981 work, prompted a re -e v a lu a tio n o f the W illow Creek Nine e a rly In 1984, .
The re -e v a lu a tio n n o t.o n ly considered proven reserves {reserves based on ca lcu la tio n s from the i n i t i a l study), but also considered the s trip p in g r a t io ( t o 'th e 5875 le v e l) , and the presence o f tre m o lite .
P rio r Work
P rio r t o the a c q u is itio n o f the W illow Creek Mine, the former op era to rs, Resource Processors, conducted d r i l l i n g programs In 1977 (16 d r i l l holes) and 1970 (28 d r i l l h o le s ). Records In d ic a te an in v e s tig a tio n o f th e W illow Creek Wine's c h lo r ite p o te n tia l was made during 1975. Four a n a ly tic a l re p o rts (dated March 13, A p r il 11, A p r il 21 and May Z, 1975) discussin g c h lo r ite p o te n tia l are attached and conclude th a t the c h lo r ite is not acceptable fo r ceramic use (May 2, 1975 re p o rt).
Montana 0407
CPC-BCALTRSCPT00000893
H is to ry o f CIM Cxplo-aHon A c t iv it ie s
Cyprus Mines Corporation (CIH) entered in to a le a s e /o p tio n agreement on the Mil low Creek property w ith Resource Processors, I n c , , 1n May 1975 The mine is s itu a te d on fo u r unpatented lode mining claim s 1n Madison
County, Montana.
1979
The E xplora tion and Mine Development Department began evalua t io n o f the p ro p e rty by c o n tra c tin g f o r and com pleting an a e ria l survey o f the p ro p e rty . This survey was completed by Interm suntain A e ria l Surveys, In c , and a topographic map a t a s a l e o f 1" - 200* was generated as a r e s u lt . In a d d itio n , E xp lo ra tio n Research Associates, In c ,, of-Los Angeles,
C a lifo rn ia , g e o lo g ic a lly mapped the inraiediata In a area so th a t a d r i l l i n g program could be la id out In an I n t e llig e n t
manner. (See ERA re p o rt dated October 6, 1979, a tta c h e d .)
1980
During 1980, a d r i l l i n g program was completed by O'Keefe D r i l l
ing Company o f Butte, Montana. T h irty -fo u r d r i l l hales were completed f o r a to t a l o f 8,B30 fe e t d r ille d . In a d d itio n to d r i l l i n g , fo u r to s ix hours o f b u lld o ze r work were necessary to prepare and provide access to d r i l l s ite s . Upon com pletion o f the d r i l l i n g over 3QQ samples (which were c o lle c te d by an on s it e g e o lo g is t) were s p l i t and sent to the CIM a n a ly tic a l lab in Lcs Angeles, C a lifo r n ia , A ll samples which were sent f o r a n alysis were subjected to th re e methods o f a n a ly s is : X-ray d iff r a c t io n , to determine m inerslogy; General E le c tr ic brightness, to determine brightness at a s p e c ific frequency; and a d d so lu b le c o n te n t, to determine the amount o f e ith e r c a lc in e or dolom ite th a t is present. The main p i t area was g e o lo g ic a lly mapped-with plane ta b le and a lid a d e a t a scale o f
l ll=50' by Cyprus personnel and a h ired c o n s u lta n t In August o f 1 1980,
1980-81
In te rp re ta tio n of a l l a v a ila b le data began once d r i l l hole lo c a tio n s were surveyed and coordinates c a lc u la te d and lab analysis data were received. In te rp re ta tio n required a t le a s t
th re e months t o in te g ra te in fo rm atio n which was gathered w h ile g e o lo g ic a lly mapping and d r i l l i n g the ares. The In te rp re ta tiv e phase, a t a scale o f 1" - SO1,-re s u lte d 1n the d ra ftin g o f 50 cross sections and 19 le v e l p la n s, and upon com pletion, reserve c a lc u la tio n s were made.
The Talc D iv is io n I n it ia t e d an a d d itio n a l d r i l l i n g program In 19S1 w ith the use o f the T-4 d r i l l i n g r i g . The purpose o f th is program was to h o p e fu lly d e lin e a te and prove a d d itio n a l reserves o f high p u rity /h ig h GEB t a lc . T h irty holes were
d r ille d f o r t o t a l footage o f 7,290 fe e t. Data based on lab analyses o f samples from f iv e holes supported e a r lie r fin d in g s and did not enhance the d e s ir a b ilit y o f t h is p ro p e rty .
Montana 0408
CPC-BCALTRSCPT00000894
Several samples ware assayed f o r gold arid s ilv e r content and economical values were not ob tain ed . (See attached assay re p o rt from Union Assay O ffic e , I n c . , October 31, 1981.)
19B4
A s trip p in g r a t io , based on a p re lim in a ry p i t design and 1981 reserve c a lc u la tio n s , was c a lc u la te d . The occurrence o f fib ro u s m in erals w ith in the W illow Creak orebody was in v e s tig a te d .
Reserve C a lcu la tio n s
A p ro fe s s io n a lly accepted method was used to c a lc u la te the reserve.. This method is a s t a t is t ic a l approach,'and I t tends to be generous. This method was acceptable f o r a f i r s t look a t the ore body.
F ir s t the carbonate zone was planimetered and t o ta l volume c a lc u la te d . The fo llo w in g rr.cthn.-j was used:
txa ro le tta. 1
Level
Area F t.2
A ' 100 B 200
(Avg. Area o W Z7 P U 3/Yd.
=2 l > -IfiL fl : . .t.
* ? t ?s Tons/Yd, = Tons
2 ,, is o F t . 2 (average area o f two le v e ls )
z5 f .--a i x 2,25 Tons/Yd, * 312.5 Tons carbonate f o r
27 i t . /Y d,
this-bench
The tru a n tity (percentage) of t a lc present w ith in the e n tire carbonate zone was then c a lc u la te d . Following 1s the step-by-step procedure which was used to make these c a lc u la tio n s :
1) The t o t a l footage o f the carbonate zone ( d o lo m ite - tilc - c h lo r lte c a lc lte ) was determined f o r each hole and then w ith in t h is tone the to t a l t a lc bearing in te rv a l was determined.
2) W ith in the t a lc In t e r v a l, the average grade o f the t a lc was d e te r mined.
3) The average grade o f t a lc w ith in the t a lc in te rv a l was m u ltip lie d times the to ta l Footage o f the ta lc in te rv a l to ob tain a "weighted
footage ta lc * o f contained ta lc .
a) The t o t a l footage o f carbonate was determined f o r a ll d r i l l ho le s, and t h is number was d ivide d in to the "weighted footage t a lc " ( t o t a l
Montana 0409
CPC-BCALTRSCPT00000895
.-..vv..^.^sgss
f o r a l l d r i l l holes) Of t a lc to ob tain a percentage of t a lc w ith in the carbonate zone.
Example Ho, 2
m
D rill tte' e
(2)
T otal Foctage Carbonate
T otal Footage T a lc Zone
T
Avg. % o f
Weighted
T alc W ithin ( Footage Talc
Ore Zone 1 I (3) X (4) i
1 1
Total
ICO 50
150
50
65 !
32.5
25
75 S
is .a
75 _ 51.3
51.3 * 150 = 34.2# contained t a lc w ith in the carbonate zone.
The q u a n tity o f ta lc o f a given GEB value was determined as fo llo w s ;
1) The t o t a l footage o f t a lc o f a given GE8 range (>S5, 80-85, 75-79 and 75) f o r a l l d r i l l holes was determined,
2) The to t a l footage o f a given GEB range o f t a lc was than compared to the to t a l footage o f the t a lc tone {Column (3 ), Example Ho. 2 ), and the percentage o f t h is grade o f t a lc w ith in the in te rv a l was o b ta in ed. T his procedure was repeated f o r etch grade o f t a lc . This represents the percentage o f a given grade o f t a lc th a t Is present w ith in the t a lc zone o f the ore body.
Example Ho. 3
U rT T T T T otal Footage T o ta l Fdotage
Bole I-
+85 GEB
80-85 SEB
T otal Footage 1 T otal Footage
75-79 SB
<75 GEB
\ 21
2 5
43
B
3 3. 1 4
Total
7
76
9
7 (-H35) * 75 (Column 3 , Example No, 2) - 9.3# +85 GEB w ith in th e ore zona
(9,3# ) x ( t o t a l tons o f t a lc ) * tons o f +8S GEB ta lc
Reserve c a lc u la tio n s showed th a t su b s ta n tia l q u a n titie s o f high b rig h t ness t a lc (Table Ho. 1} did not e x is t on th is pro pe rty. The to t a l
m in eralize d zone (d o lo m ite -ta lc -c h 1 o r1 te -ta lc o s e rock types) was ca lcu la te d to be approxim ately 2.S m illio n to n s , o f which 772,500 tons (30.9#) was t a lc . Of th e 772,500 tons of t a lc , only. 37,982 tons (5.0#) was +85 GEB, and, based on these r e s u lts , i t was recommended by the
E xp lo ra tio n and Mine Development Department th a t the property be dropped,
Montana 0410
CPC-BCALTRSCPT00000896
S trip p in g Ratio
In o rd e r to f u l l y understand the v ia b il it y o f the W illow Creek Mine w ith respect to tod ay's (1984} economics, the s trip p in g r a t io was c a lc u la te d , ftp industry-accepted method was employed to cal cut ate the volume o f m a te ria l to be removed to recover the proven t a lc reserves. A p re lim in a ry open p i t mine was designed w ith an o v e ra ll p i t slope o f 45s, and included removal o f m a te ria l from le v e l 6875 (toe o f p i t ) to le ve l 745.0, a depth o f 575 f t . below present p i t bottom. Upon completion o f the p i t la y o u t, each le v e l was planimetered and tonnage was c a lc u la te d . (See Example Ns. I . )
An a d d itio n a l 15S o f the t o t a l calcula ted tonnage was added to a llo w fo r s a fe ty benches, benches and haulage roads, This resulted in 71,095,580 tons o f m a te ria l (waste plus ore) to be removed.
A n tic ip a tin g 75S recovery (hated on CIM past experiences), the fo llo w in g s trip p in g r a tio s would re s u lts
Ore Categories A ll Contained Talc
+75 GEfi +80 6EB +85 SEE
(Tons) Contained
Talc 775,136
829,441
153,128 37,982
< Recovery
.75 .75 .75 .75
Tons of Recoverable
Talc ...531,352...
172,081 118,596
28,487
i ons of Waste 21,314,228
21,723,499 21,776,904 21,867,093
Waste/ Ore
T T iT 126; 1 134:1 768:1
Note: See attached map showing p i t design.
Economic parameters used in 1981 as w e ll as those used in 139-1 show th a t s trip p in g r a tio s o f these magnitudes are out o f the question f o r ClM to reopen and operate t h is mine.
E valua tion Costs
I t is estim ated th a t since 1979 CIH has invested over $100,003 in order to evaluate t h is p ro p e rty . (See attached memo to Ralph S o d e ll, March 30, 1984.)
Montana 0411
CPC-BCALTRSCPT00000897
TABLE HO, 1
1981
RESERVE CALCULATIONS
PLAWIMETEREQ VQLUHES (MINERALIZED ZONE)
fi-S Cross Sections; 2,4S,200 Tons
Cross Sections; 2,513,507 Tons
Level Plans;
2,514,889 Tons
Average:
2,508,532 Tons
Percent E rror:
K-5 vs. E-H
ha#
E-W vs. Level Plans . i
N-S vs. le v e l Plans M
Tonnage Breakdown;
Comeodlty Talc
Percent of Structure
30.S
Tonnaqe 775,136
C hlorite
SO.fl
757,611
Oolomfte/Talcose
3 8 .5%
965,735
Tonnare b,v GEB {Based on Footaqel
SS*
80-84 zs-eo Below 75
37,982 Tons * 120,146 Tons = 71,313 Tons 545,695 Tons
Montana 04X2
CPC-BCALTRSCPT00000898
Tremo1it a Occurrence
A n a ly tic a l data Rased on a n alysis o f chip samples from the W illow Creek .Mine have confirmed the presence o f t r e n a ilte throughout the down dip extension o f the ore body.
A d e ta ile d study o f the t r e s o lit e occurrence was made in 19B4 in order to determine i f the tre m o llte was zoned and whether s e le c tiv e mining methods could be employed to mine the t a lc and not touch the tre m o llte . The tre m o llte was present in 16 holes (see Table Ho. 2 ). Each hole'was looked a t to determine where the tre m o lite occurred w ith in 1 t w ith re la tio n s h ip to the hanging w a ll, fc o tw a ll, carbonate zone, and the h o riz o n ta l d is tr ib u tio n w ith in the area. A phone c a ll was made by R. L. Weeks to P a tric ia C o lv ille (S upervisor, Minerals C h a ra cte riza tio n , Cyprus Research Lab) to confirm, the la b o ra to ry data, and a fte r ad d itio n a l work, Mrs. C o lv ille v e rifie d th a t the s p e c ific mineral tre m o lite was present and Is the fib ro u s v a rie ty . The occurrence o f the m ineral tre m o lite a t the W illow Creek Mine has been noted by R. B- Berg o f the Montana Bureau o f (lines and Geology (Montana Bureau o f Mines and Geology Memoir 95, 1979, p. 46)
Based on the an alysis o f the above d a ta , i t can be concluded th a t the tre m o lite is not zoned and th a t s e le c tiv e mining methods could not be succe ssfully employed to avoid mining tre m o llte . As in dica ted on. the planview map, tre m o llte . occurs along 80 percent o f the s trik e length of the ore body. A d e ta ile d look a t each hole containing tre m o llte revealed the d is tr ib u tio n o f tre m o lite to be random. T rem olite was found to occur w ith in the carbonate zone, the hanging w a ll gneiss, fo o tw a l! gneiss, a t both the contact o f the hanging w a il gneiss and carbonate zone and the fo o tw a ll gneiss and carbonate zone. Q uantity o f tre m o llte in these occurrences ranged from a trace to 20 percent,
TABLE HO, 2
TREMOLITE OCCURRENCES IN DRILL HOLES AT WILLOW CREEK MINE
WC-3-S0 (1 -Z ); WC-10-80 {tra c e o n ly ):
WC-ll-80 (trace o n ly ):
WC-12-80 (le s s than <?$): NC-13-80 (tra c e ):
In F,W. and H.W. None present w ith in car bonate zone.
Occurs w ith in c h lo r ite zone, a t contact o f c h lo r ite zone and taic/ca rb o n a te zone and w ith in zone o f best ta lc .
Occurs w ith in c h lo r ite zone throughout ho le . Occurs a t lower contact where going from t a lc back to c h lo r ite w ith in t a lc zone.
W ithin carbonate zone.
W ithin zone of best ta lc .
Montana 0413
CPC-BCALTRSCPT00000899
CP-S-S {tra c e -1 0 *):
W ithin carbonate zone and a t contact o f
carbonate zone and f.W . f a llin g w ith in both zones.
VC-S-60 (tra .ce .-l*):
W ithin ta lc -c h lo rite zone, present w ith in zona o f best GE3S (B 3.6 ).
WC-401 (1 0 *):
W ithin F.W. a t contact o f carbonate and F,W.
WC-4Q3 (5 ) :
W ithin ta lc -c h lo rite zere.
WC-4Q7 (1-lOJf)
W ith in c h lo r it e - t a le zona, and dolo m itee a le ite - ta lc zone (not associated w ith F.W. or H.W.).
WC-.408 (1 -1 0 *):
W ithin H.V. and w ith in d o lo m ite -c a lc ite zone.
WC-409 (tra c e ):
W ithin d o lo m ite-talc zone.
WC-410 (tra ce -2 0 1 ):
W ithin H.W,, w ith in d o lo m ite -ta lc , t a lc dolom ite zone.
WC-411 (tra c e -2 ) :
W ith in ta lc -d o lo m ite zone.
WC-413 (W ):
W ithin ta lc -e h lo rite -d o lo m ite zone.
VC-416 (1-1 0*):
W ithin d o lo m ita -c a lc ite -ta lc -c h lo rite zone.
Graphite and P.yrite
The presents o f both g ra p h ite and p y rite was noted in the t a lc zone in d r i l l holes-eatsplated du rin g 1980. The presence o f both o f these m inerals has the e ffe c t o f lowering th e b righ tn ess o f the t a lc .
Conclusions
Based on economic c r it e r i a in use by Cyprus In d u s tria l M inerals in 19B1, reserve studies in d ica te d m ining was not economic. A new look a t the economics in lig h t o f CIK t a lc requirements in 1984 which g re a tly reduced the reserve c r it e r i a (a minimum of 20,000 tons o f ere w ith a GS o f +86 and no gre a te r than a 20.-1 wasta/ore r a t io ) showed th a t mining would not be economic due to high s trip p in g r a t io s . Above a l l , the presence of the tre m o lite throughout th e carbonate, zone negates t h is
property fo r consideration fo r mining.
Ft. L. Weeks
Montana 0414
CPC-BCALTRSCPT00000900
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Montana 0416
CPC-BCALTRSCPT00000902