196 
CONTRIBUTION'S    TO    ECONOMIC    GEOLOGY,   1903. 
[BULL.  221 
The  average  composition  of  the  ore  (from  information  furnished  b;i s0 
the  owners)  is: 
Average  composition  of  ore  of  Copperfield  mine. 
Per  cent. 
Copper 3.  31 
Inn, - 30-39 
Sulphur 14.  71 
[nsoluble - 36.  67 
An  interesting  feature  of  the  ore  and  one  that  has  an  importan 
bearing  on  its  treatment,  is  the  brittleness  of  the  quartz,  so  that  whei 
the  ore  is  subjected  to  coarse  crushing  it  yields  about  40  per  cen 
of  lines,  which  carry  more  silica  than  the  lump  ore.  The  followin| 
analyses,  kindly  furnished  by  the  owner,  show  the  results  of  actua 
tests  on  large  samples  of  No.  1  ore: 
<  1  nalyses  of  coarse  and  fine  ore. 
Copper 
Iron 
Sulphur 
Silica  and  insoluble 
Coarse. 
Per  cent. 
4.45 
33.5 
20.5 
31.1 
Fine. 
Per  cent. 
1.7( 
25.3 
13.6 
45.4 
ELIZABETH   MINE. 
History. — The  Elizabeth  mine,  at  Copperas  Hill,  near  the  town  oi 
South  Strafford,  and  about  6  miles  due  south  of  Copperlield  (Ely 
mine),  is  the  oldest  copper  mine  of  the  State.  It  was  opened  in  1793, 
the  magnetic  pyrite  being  used  for  the  manufacture  of  copperas  (sul- 
phate of  iron).  The  manufacture  of  copperas  was  continued  for  many 
years,  until  the  discovery  of  increasing  amounts  of  copper  led  to  the 
working  of  the  property  for  that  metal  and  the  building  of  a  smelting! 
plant, 
Production. — The  production  was  2,804  tons  in  1883,  and  3,299  tons 
from  1881  to  1884. 
Equipment. — The  mine  is  equipped  with  a  power  plant,  4-drill  air 
compressor,  with  ore  bins,  crusher,  picking  belt,  and  a  small  smelter! 
plant. 
Development. — The  early  working  of  the  property  consisted  of  open- 
cut  work  with  a  60-foot  drift.  In  1886  a  vertical  shaft  160  feet  deep! 
was  sunk  in  the  hanging  wall,  cutting  the  ore  at  100  feet  in  depth  and 
continuing  in  it  to  the  bottom.  From  this  shaft  a  level  was  driven 
southward  at  50  feet  below  the  surface,  connecting  with  the  open-cut | 
work  200  feet  south  of  shaft.  A  level  was  also  driven  300  feet  to  the 
north.     Another  level  at  110  feet  in  depth  was  driven  100  feet  to  the 
