38  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1906,  PART    I. 
the  mines  and  mills  with  1,100  horsepower.  A  300-ton  concentrator 
was  built  just  below  the  collar  of  the  Bimetallic  shaft.  From  1898 
to  1904  the  mines  produced  about  $1,000,000  a  year.  In  August, 
1905,  they  were  shut  down  on  account  of  the  low  price  of  silver  and 
the  decreasing  value  of  the  ore.  Subsequently  they  have  been 
reopened  above  the  drain  tunnel  and  the  leasing  system  has  been 
adopted  by  the  company.  In  the  summer  of  1906  about  100  men 
were  engaged  in  the  mines  and  in  sorting  the  old  Granite  dumps. 
The  total  production  of  the  two  mines  has  been  something  over 
$32, 000,000  in  silver  and  gold,  from  which  nearly  $15,000,000  has 
been  paid  in  dividends;  of  this  amount  the  Granite  produced  more 
than  three-fourths  and  its  dividends  have  been  about  $13,000,000. 
This  represents  net  profits,  since  the  original  purchase  price  and 
other  funds  advanced  by  the  syndicate  were  returned  with  interest 
and  the  extensive  hoisting  and  reduction  plants  were  built  from  the 
proceeds  of  the  mine. 
The  mine  was  worked  from  five  drift  tunnels  and  two  deep  shafts, 
and  is  cut  by  a  long  adit  which  drains  the  Granite  mine  between 
levels  14  and  15,  and  the  Bimetallic  mine  at  level  10.  The  Granite 
(Ruby)  shaft  is  about  1,550  feet  deep,  and  the  Bimetallic  (Blaine) 
shaft  is  about  1,800  feet  deep.  The  vein  has  been  followed  and 
stoped  as  far  as  2,600  feet  below  the  surface  and  there  are  altogether 
more  than  20  miles  of  drifts  and  crosscuts.  At  present  the  mine  is 
under  water  below  the  adit  level. 
GEOLOGY. 
The  country  rock  is  a  medium-grained  granite,  composed  chiefly 
of  feldspar,  quartz,  mica,  and  hornblende,  which  is  cut  by  small 
aplite  dikes.  As  a  rule  it  is  not  greatly  decomposed  in  the  region  of 
the  veins,  but  is  as  solid  there  as  elsewhere,  although  in  many  places 
in  the  walls  of  the  veins  the  ferro-magnesian  minerals  have  altered  to 
green  silicates  for  a  short  distance  away.  A  considerable  amount  of 
the  country  rock  is  included  in  the  vein  as  angular  blocks  broken  from 
the  walls  and  at  numerous  points  the  vein  splits  to  inclose  horses  of 
the  granite.  The  country  rock  has  not  been  replaced  by  ore  to  any 
great  extent ,  and  the  granite  of  the  walls  or  horses  can  not  be  worked 
profitably.  The  walls  are  everywhere  well  defined  and  make  a  clear 
division  bet  ween  the  vein  and  country  rock. 
ORE    DEPOSITS. 
Gt  neral  distribution  of  ore. — The  Granite  vein  strikes  about  N.  75°  E. 
and  its  usual  dip  is  about  75°  S.,  although  in  places  it  becomes  nearly 
vertical  or  is  even  overturned,  dipping  toward  the  north.  Its  width 
varies  from  1  to  20  feel .  Along  its  strike  it  has  been  stoped  for  a  dis- 
tance of  4,500  feet  and  in  depth  about  2,  600  feet.     As  already  stated, 
