RedRocktalcdeposit,SierraCounty,
NewMexico
tal dimension.Basedon measureddimensions
of the body in the mine and at the surface,the
depositcontainsabout 62 tons of talc per foot
of depth. If the body is projectedto 100 ft
below the lower level, a probablereserveof
about6.500tonsof talc is indicated.
Mneixviecros,iAt yl bouf q u e r q u e , N M
b y J P a uFl i t z s i m m o n s a n d V i n c e n t C . K e l l y , D e p a r t m e n t o f G e o l oNgeyw, U
The Red Rock talc depositoccursin Hembrillo Canyonon the Sierra-DofiaAna County line midway along the long north-trending
New
San AndresMountainsin south-central
Mexico. The canyonis erodedapproximately
two-thirdsof the way throughthe rangefrom
its easternbase. The deposit and mine are
locatedin SE%NW% sec.l, T. 16 S., R. 3 E.
in SierraCountyjust north of the Sierra-Doha
Ana line. Entry to the area is restricted
becauseit is within the White SandsMissile
Range.Accessis by pavedroad that follows
the easternbaseof the mountains42 mi northward from US-70 (linking Las Cruces and
Alamogordo).Approximately6 mi up the canyon (westward)via a rough gravel road, a
precarious4-wheel-driveroad leads abolt 3/q
mi to the mine (fig. l). The depositoccursat
5,050ft, approximately500 ft up a steepspur
slopetowardKaylorMountain(7,050f0.
Geologicseiting
Talc body
Foliation in the talc body is parallelto the
Reportedly,however,Oscar M. Nelson dis- foliationandlayeringof thecountryrock.The
coveredthe depositand interestedNateSmith, foliation appearsin the orientation of talc
of lenticularaggreNelsonH. Cross,and L. C. Butlerin the prop- grainsand in the presence
erty.TheRedRockclaimwasfiledSeptembergates0.1-0.3 mm long and approximately
l,1941, by Ritch, Cross,and Butler. SeePage 0.02 mm wide at the thickestpart of the lens.
(1942)for earliesthistory and production.On The lensesare alignedparallelwith the foliaMarch 30, 1942,the Big Horn Talc No. I was tion. Talc flakeswithin the lensesaregenerally
located,overlappingthe southeastend of the orientedtransverseto the generalfoliation of
Red Rock claim.The main entryto the mineis the rock. The grain sizeof the talc is very fine
on the Big Horn claim but entersthe RedRock and ratheruniform (fig. 3).
The main part of the body seemsto be very
claim 36 ft insidethe portal. This adit, begun
in January 1943, was known as the Maire pure, monomineralictalc; but, in the outer 2
mine (Walter, 1953). The property was or 3 ft of the body, scatteredremnantsof caroperatedby Sierra Talc Company under a bonate (dominantly calcite)and chlorite apworking agreementbeginning pear. The presenceof thesetwo components
bond-and-lease
October 14, 1942.SierraTalc reportedlyad- explainsthe small amountsof calcium,iron,
vancedmoney to Ritch and paid him $12.50 and aluminum obtainedin chemicalanalyses
per ton of talc deliveredto Engle, New Mex- (tablel). The talc body gradesratherabruptly
ico. About the sametime, the United States to slightlybandedquartz-chloritephyllite;the
spent $5,670 building a 10-mi accessroad bandingis causedby variableproportionsof
from the west that involved expensivecuts quartzand chlorite.Lighter bandsare approxthrough the limestonecliffs below Hembrillo imately 80 percent quartz and 20 percent
spent $3,000building chlorite;thedarkerbandsareabout20percent
ronto the mine road. A
quartz and 80 percentchlorite. Intermediate
rf talc was reportedly proportions are also present. The chloriteosit between1942 and dominantbandsarethickerthan chlorite-poor
)roperty was appropri- bands; chlorite probably forms over 60 percent of the rock. In the zone of gradation,
isilerange.
te a lenswithin sericite however,numerousstringersof calcite and
h becomesincreasingly quartz are present,commonlyexhibitingemapproached.The lens bayed zonesof corrosionor replacementby
I in length, is exposed chloriteand talc.
't,
All marginal and country rocks contain
and hasa width that
of
:agesroughly8 ft. Dip- numerouspatchesand granularaggregates
schist a duskyto opaquematerialthat is chalk white
of the associated
'il::
::'il'J,,'ffi
lil*.T*'.""1r:'il:H::1il."J.T::o,Hl:"Jl
westernslopeof themountains.
A narrow belt of Precambrianrocksextends
nearlythe entirelength of the easternsideof
the rangebeneaththe Paleozoicsection(fig.
2). The Precambrianrocksaremostlygneisses
and granites, with short stretchesof interspersedschjsts,quartzites,and phyllites.Sills
and dikesarelocallypresentas dioritic to gabbroic or diabasicrock intrusions.A thick section of phyllites and quartzites occurs in
Hembrillo Canyon. Theserocks strike about
N. 40-50" W., with dips rangingfrom nearly
vertical to about 70" NE. The metamorphic
sectionis at least 12,000ft thick, possibly
twice that if the section is not isoclinally
folded and repeatedin its northeasternpart.
In the immediatevicinity of the Red Rock
deposit, the rocks are reddish-brown,darkgray, or greenishphyllitesand sericiticschists,
intrudedlocallyby diabaseor gabbro.
Talc mine
The Red Rock talc depositwas supposedly
discoveredby Watson L. Ritch, Jr., when a
horse he was riding slipped on the talc.
August1980
New Mexico Ceology
FIGURE l-Vrew NoRTHEAST
oF MAIN woRKrNcs, Red Rock talc claim. Framework of sorting shed in
foreground; arrow indicates marker at southeastend line of claim.
material is now leucoxene,derivedfrom the
original sphene.Occasionalgrainsof muscovite and more diffuse patchesof biotite are
presentin the rocks at the margin of the talc
body. The biotite seemsto be geneticallyrelated to crosscuttingveinletsof iron-stained
material.The biotitic mica is darkestnext to
these reddish-brownveinlets and grades to
colorlessmica within a few millimeters.The
bulk of this rock consistsof quartz and
chlorite.
On the surfaceat the northwestend of the
body, the zoneof talc is scarcelymore than I
ft wide. It containsnumerousinclusionsof
carbonate,occasionalchlorite, and scattered
patchesof granular sphene-leucoxene.
This
zone of dominant talc gradesnortheastto a
strongly sheared,brecciform phyllitic rock
with flaser-like fragments consisting of
quartz-richrocks and minor chloriteand surmaterial,whose
roundedby chlorite-abundant
foliation bendsaround the fragments.To the
southwest,the talc-abundantzone givesway
to a shearedcarbonatestainedwith iron oxide
and containing occasional lenses of finegrained quartz. Within 3-4 ft the rock
becomesquartz-chlorite phyllite and then
quartz-chlorite-sericite
schist.
The talc body seemsto havebeenformedby
replacement
of carbonateand possiblyquartzchloritephyllite;theserocksare presentin the
stratigraphicposition of the talc beyondthe
end of the body. The occurrenceof remnants
and quartzof carbonate,quartz-carbonate,
chloritein the marginalpartsof the talc body
providesmore direct evidence.Many of these
remnantsexhibit embayedand corrodedrelations with the talc. However, parallelismof
shearingplanesand generalschistosityof both
the talc body and the country rocks suggesta
practically simultaneousorigin for all the
rocks. If the talc formed after the episodeof
low-grademetamorphismthat producedthe
country rocks, the origin of the talc was still
by shearingmovementsthat left
accompanied
imprints upon both the talc and the country
rocks, and the shearingmovementsoccurred
along the sameplanesinvolvedin the earlier
metamorphism.The shearingmovementspossibly facilitated the migration of the components necessaryfor replacementof carbonate and quartz-chloritephyllite by talc.
Meladioritedikes (80 percentoriginal augite
and l5-20 percentintermediateplagioclase)
occur in the vicinity of the talc body, but
evidencedoes not suggestthat the talc is
geneticallyrelated to such intrusive masses.
Contacts betweenthe talc and meladiorite
dikes do not exist. Furthermore.metamorphism or alterationof the country rock adjacentto the dikesis not found.
Ten sampleswere taken acrosstalc widths
of 5-12 ft in the workingsfrom the surfaceto
the lower level, shown in the accompanying
minemaps(figs.4 and 5). Maps of the surface
and mine workingsshow the pinchingout of
the talc body to the northwestin the outcrop
(fig. 6), the uppercut, and the lower level.The
southeastpinching of the orebody is only
observedin the lower adit. Analysesof these
F
Io 6 0
E X P L A N A TI O N
P o l o o z o i cr o c k g
ffi
Precombrion
Tertiory inlrusive
ITK
Tcrtiory I
Creloceous ro
Foulf
boll on
sidc
downlhrown
Z
I
Syncline
Red Rock mine
330
FIGURE 2-Ceoloctc
unp or SeN Anones MoulretNs.
New Mexico Geolog!
August1980
samplesare shown in table l. Analysesmade
by others of selectedtalc samples have yielded
s i l i c ap e r c e n t a g eosf 6 1 . 1 8a n d 6 1 . 6 7( C h i d e s ter, Engel, and Wright, 1964).
NW
SE
;1
f
| .o\"
Upper\-cul
-i';-i
-:
r--l:
?1
I
I
\N
I
+6
5,O50
.a\
--s'it _
q
*lgi
.re
.\o'
I
ol
-rO
,olz
2,":
Lower
level
-l
--;t
'+g
(3Elte
*
-lp
ele
FIGURE 5-LoNcrruorr.rALsEcrroN.Reo Rocx relc woRKrNGS.
TABLE l-Curvrcu
ANALysEsoF vARrous pARTs
oF THE TALCBoDY. Location of samples given in
figs. 4 and 5. Analyses by John Husler.
FIGURE 3-ScnNNrNc ELEcTRoN MrcRoscopE
pHoroMtcRocRApH oF TALC pARTlcLEs; enlargement approximately x 1,400 (courtesy University
of New Mexico School of Medicine. bv D. G.
Brookinsand R. Hicks).
Sample
FezOr
ALO!
CaO MnO
6A
6B
6C
6D
7
2.50
l.50
r .35
3.72
6.33
2.08
3.97
14.5
2.9t 0.284 0.023 0.001 27.2
4.06 0.226 0.03140.006 28.2
0.s39 0.t29 0.015 0.n2 34.2
3 . 1 5 0 . 3 1 00 . 0 0 5 0 . 0 0 4 2 8 . 3
6
9
l0
ll
l2
XrO
Mgo
3 . 0 2 4.05 0.226 0.015 0.002 28.6
l . 5 t 2.74 0.129 0.007 0.001 29.7
4 . 5 3 0 . 2 5 90 . i l 6 0 . 0 0 7 0 . 0 0 2 3 1 . 0
0.945 l . l 9 0 . 0 9 7 0 . 0 1 3 0 . 0 0 2 3 t . 0
1.04 r.85 0.180 0.0t2 0.002 26.4
References
Chidester,A. H., Engel, A. F. J., and Wright,
L. A., 1964,Talc resources
of the United States:
U.S. GeologicalSurvey,Bull. 1167,p. 37-38,
45-47
Page,B. M., 1942,The Hembrillo and Red Rock
talc mines,SanAndresRange,New Mexico:U.S.
GeologicalSurvey,report (on file at New Mexico
Bureauof Minesand MineralResources),
l7 p.
Walter, A. S., 1953,Appraisalreport on the Red
Rockclaim:U.S. Army Corpsof Engineers,
25p.
Za'n
Z
| .57
0.858
|.79
0.500
0.929
NorO
ui^z.
FIGURE 6-Vrew NoRTHwESTrNro opEN cur AND
INcLINETo srope showing mine stalls in place and
talc in face of cut.
!
New Mexico uranium statistics
A report from the U.S. Departmentof Energy, May 7, 1980, lists New Mexico $50/lb
uraniumreserves
on JanuaryI , 1980,as482million tons of ore at a gradeof 0.09percentU3O6
.
This gradegives449,0@tons of UrOr or 48 percentof $50/lb ore in the United States.In New
Mexico,6.9 million tonsof ore wereprocessed
in 1979;the ore contained8,040tonsof UrOEor
44 percentof productionin the United States.Exploration and developmentdrilling in New
Mexicodroppedto 6 million ft in l97g from l0 million ft in l97g.
FICURE 4-PlaN
AND sEcrroN. Rpo Rocx rnlc
WORKINCS.
38
August1980
New Mexico Ceolog,