PERMFILE134862

• Permit No: C1981014
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: EXHIBIT 24 ALLUVIAL VALLEY FLOOR INVESTIGATIONS
• Media Type: D
• Archive: No

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~ mile respectively. The gradient fran the lowest contributing strewn to
the confluence with Nctviln Creek was 385 feet over 1.42 miles fora rate
of 200 feet par mile. ,
Topographically the streams of the upper part of th NSB form steep,
narrow, V-shaped valleys, eroded from outcrops of biotite gneiss and one
smeil area of landslide deposits in the western portion of the basin.
These valleys are up Lo 140 feet deep and generally rot over 500 feet In
width at the top. The streams' gradients decrease as they enter the
southwestern part of the permit area at an elevation of 6,700 feet.
(Rockvale Quadrangle). The valley shape remains steep-sided where 4 of
the streams have eroded through pediment deposits Into the underlying
Poison Canyon, Raton and VermeJo formations. The streams flaw In
• valleys generally 25 to 50 feet in depth and less than 500 feet wide at
the top. As the streams approach the Black Diannnd Mine area a mile
north of the permit boundary, the valley becomes shallower and the
stream barely cuts through the pediment deposits into the berock. The
valleys of the NSB are deeper on the permit area than adJacent points of
the Newlin Creek valley CproJected normal to Newlin Creek). The valley
of the main drainage in the NSB Is 60 feet lower In elevation than
Newlin Creek where It crosses the southern boundary of the permit area,
and is 30 feet laver than Newlin Creek where it passes the Black Diamond
Mine In the SW 1/4 Section 24, T205, R70W.
A)1wia1 deposits by the streams In the NSB are generally
Inextenslve, very irrigular, rocky,•and mixed with coilwiun from valley
wells. The valleys in the upper two-thirds of the basin carpristng the
northwestern permit area, have ro contiguous a11w1a1 deposits over a
few hundred feet long and a few feet wide. The strewn channel occupies
the entire valley floor. This alluvium irregularly mantles bedrock in
the narrav valley and is comprised of reworked rocky collwial material
which results in a very bouldery, cobbly, gravelly mixture in a sand
matrix. The stream valley In the lower one-third of NSB contains narrow
strip-shaped deposits of bouldery allwlun In patches over bedrock. The
pediment deposits contribute much bouldery, cobbly gravel to the stream
load but no cantlrwa~s allwial deposit exists in the strewn valleys of