NICKEL  DEPOSITS  OF  NICKEL  MOUNTAIN, 
OREGON. 
By  (i.  F.  Kay 
INTRODUCTION. 
For  more  than  twenty-five  years  hydrated  nickel  magnesium  sili- 
cates  have  been  known  to  occur  on  Piney  or  Nickel  Mountain  near 
Riddle-,  in  Douglas  County,  Oreg.,  and  it  lias  been  hoped  thai  devel- 
opment would  prove  the  presence  of  these  minerals  in  sufficient  quan- 
tity for  economic  purposes.  There  seemed  to  he  reason  for  t  his  hope, 
since  the  deposits  are  in  mineral  content,  in  modes  of  occurrence,  and 
in  their  associations  very  similar  to  the  deposits  of  New  Caledonia! 
whose  mines  are  the  second  largest  producers  of  nickel  in  the  world. 
But  as  yet   no  commercial  ores  have  been  produced. 
During  the  summer  of  L906  Mr.  J.  S.  Diller  and  the  writer  were 
engaged  in  mapping,  for  folio  publication,  the  rocks  of  the  Kiddles 
quadrangle,  in  which  the  nickel  silicates  occur.  In  connection  with 
this  work,  the  writer  made  a  special  study  of  the  ores,  in  order  to  gerf 
if  possible,  ;i  clearer  idea  of  the  modes  of  occurrence  and  the  probable 
extent  of  these  interesting  deposits. 
Thanks  are  due  lo  Mr.  \Y.  Q.  Brown,  of  Riddles, for  kindness  in  the 
field  and  for  information  in  regard  to  the  development  and  other 
features  of  the  ore  bodies. 
The  literature  on  these  deposits  is  as  follows: 
Clarke,  I".  VY..  Some  nickel  ores  from  Oregon:  Am.  Jour.  Sci.,  3d  ser.,  vol.  35,  L8883 
pp.  483    188;  Bull.  I'.  S.  Geol.  Survey  No.  60,  L890,  pp.  21   26. 
Analyses  are  given  of  the  nickel  >i  1  icn t «s  of  the  country  rock  (Saxonite),  and 
of  the  olh  in-'  of  the  country  rock.  J.  S.  Diller  gives  the  results  of  a  microscopical 
studj  "I  Hi"  saxonite  and  <>!'  the  ore.  The  evidence  points  to  the  saxonite  as  the 
source  of  the  nickel. 
Von  Foi  llon,  II.  I'...  <>n  Toddles.  Oreg. :  Jahrbuch  K.  k.  geol.  Reichsanstalt,  vol. 42, 
Vienna,  L892,  p.  223. 
The  minerals,  their  associations,  and  their  probable  origin  are  described.  The 
ores  are  thought  to  have  resulted  from  the  decomposition,  by  superficial  weather- 
ing, of  the  country  rock,  which  he  calls  harzburgite.  The  processes  of  alteration 
are  fully  discussed. 
Austin,  W.  L.,  The  nickel  deposits  near  Riddles,  Oreg. :  Proc.  Colorado  Sci.  SocJ 
January,  (i.   1896. 
The  location  of  the  deposits,  their  method  of  occurrence,  the  development  work, 
the  probable  origin  of  the  ores,  and  the  metallurgy  of  the  ores,  are  fully  discussed. 
Tie-  theory  of  deposition  from  ascending  thermal  waters  is  advanced. 
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