CONTBIBUTIONS    TO    ECONOMIC    GEOLOGY,   1903.  [bull. 225. 
In  the  Crowe  shaft  a  sample  was  obtained  by  making  a  cut  across 
the  lower  bench  of  coal  18£  inches  in  thickness.  This  was  analyzed 
by  Mr.  Sullivan  with  the  following  result: 
Analysis  of  lowest  coal  in  Crowe  shaft,  Lower  field. 
Per  cent. 
Moisture 1-76 
Volatile  combustible  matter 36.  65 
Ash,  light  reddish 34.  78 
Fixed  carbon 26.  81 
Sulphur 1.  91 
Silica  in  ash 51.  5 
Coke Dull,  not  swollen,  friable. 
The  striking  feature  of  the  above  analyses  is  the  high  percentage 
of  ash,  which  in  the  samples  taken  runs  from  31  to  51  per  cent.  At 
first  this  heavy  percentage  seems  to  be  prohibitive,  but  when  it  is 
considered  that  much  of  the  Colorado  and  New  Mexico  coal  delivered 
in  this  region  probably  does  not  run  under  17  per  cent  of  ash,  and 
some  of  it  exceeds  this  figure,  it  is  apparent  that  local  coal,  even  with 
the  heavy  percentage  shown  in  the  above  analyses,  may  be  able  to 
stand  in  competition.  It  is  possible  that  the  ash  may  be  reduced 
by  washing,  if  the  coal  is  transported  to  Gila  River,  where  sufficient 
water  is  available  for  this  purpose.  The  hard  bench  of  the  coal,  how- 
ever, has  a  rather  high  specific  gravity,  so  that  the  separation  of  the 
coal  and  shale  would  not  be  an  easy  matter. 
One  of  the  greatest  demands  for  fuel  in  this  country  is  for  coke  to 
supply  the  copper  smelters.  In  the  early  days  this  was  brought  from 
abroad  at  a  cost  of  from  $50  to $75  per  ton,  but  recently  with  increased 
railroad  facilities  the  region  is  supplied  with  Colorado  and  eastern, 
coke  at  a  cost  of  from  $10  to  $15  per  ton.  The  commercial  value  of 
the  Deer  Creek  coal  depends  largely  on  whether  it  will  produce  a  coke 
that  can  be  used  in  the  copper  smelters  and  that  can  be  supplied  at  a 
cost  below  that  obtained  for  eastern  coke. 
As  will  be  seen  from  the  analyses,  almost  all  the  coals  of  this  field 
will  produce  coke,  but  as  tested  in  the  laboratory  the  upper  bed,  or 
that  shown  in  the  Reed  shaft,  is  the  most  promising.  This  bench  of 
coal  has  a  thickness  of  about  15  inches.  The  lower  bed,  as  sampled  in 
Crowe's  shaft,  yields  an  inferior  coke,  so  that  probably  it  can  not  be 
depended  on  unless  it  is  found  in  actual  practice  that  the  coke  is  of 
better  quality  than  that  produced  in  the  crucible.  Generally  it  is 
recognized  that  all  laboratory  tests  of  coking  coals  are  inadequate; 
therefore  it  is  desirable  in  all  cases  to  make  practical  tests  in  the  field 
before  beginning  operations. 
During  the  process  of  coking  in  the  ordinary  beehive  oven  the  vola- 
tile, combustible  matter  is  driven  off  and  also  a  considerable  percent- 
age of  the  fixed  carbon  is  burned  up.  Owing  to  this  reduction  in  the 
percentage  of  the  fuel  part  of  the  coal,  the  percentage  of  ash  in  the 
