DUKANGOGALLUP    COAL    FIELD,    COLORADO-NEW    MEXICO.        255 
Ft.  In. 
Fire  clay 2 
Sandstone 5 
Draw  slate 1    6 
Coal— bed  No.  3| G    3 
Fire  clay 2    6 
Sandstone,  shale,  and  thin  coal  seams 20 
Coal,  with  many  shale  partings— bed  No.  4 3 
Fire-clay  floor. 
Sandstone 20 
Coal— bed  No.  5 f,    6 
I  The  lower  subgroup  contains  four  workable  beds,  known  as  the  Crown  Point,  Thatcher, 
Black  Diamond,  and  Otero.  The  following  is  a  partial  section  of  this  subgroup  at  the 
ptero  mine: 
Section  of  lower  coal  subgroup  at  Otero  mine,  1\  miles  east  of  Gallup,  N.  Mex. 
Ft.  In. 
Coal— Crown  Point  bed 3    5 
Shale 8 
Coal 1     5 
Sandstone 11 
Coal— Thatcher  bed 4 
Shale  and  sandstone 6 
Shale 9 
Coal— Black  Diamond  bed 1    6 
Sandstone  and  shale 88 
Coal 1    2 
Shale 9 
Coal—Otero  bed 3    2 
Shale(V). 
Of  the  dozen  mines  in  the  district,  those  now  producing  are  the  Weaver,  Otero,  Heaton, 
tocky  Cliff,  Union,  and  Clark.  The  Weaver  mine  is  the  most  important.  Its  record  out- 
fit is  2,250  tons  per  day.  Its  gangways  extend  3,000  feet  in,  and  diamond-drill  prospects 
i,000  feet  beyond  the  working  faces  show  that  the  coal  beds  continue  at  least  to  that  dis- 
ance  without  perceptible  change,  either  in  thickness  or  quality  of  coal. 
The  total  output  of  the  district  in  1903  was  569,362  short  tons  and  in  1904,  441,865  short 
ons.  The  decrease  in  the  output  for  1904  is  due  in  large  measure  to  the  introduction  of 
uel  oil  as  a  substitute  for  coal  on  the  locomotives  of  the  Atchison,  Topeka  and  Santa  Fe 
Railway.  The  market  value  of  the  coal  at  the  mines  is  $1.32  per  ton.  The  number  of 
nen  employed  in  the  district  is  700. 
The  coal  of  this  district  is  a  black  shining  lignite  which  approaches  bituminous  coal  closely 
n  composition.  Its  principal  defect  is  that  it  crumbles  on  exposure  to  the  air  and  is  so 
ight  that  when  used  in  locomotives  a  large  proportion  of  it  is  carried  out  of  the  stack. 
Samples  for  chemical  Analysis  were  taken  at  the  Weaver,  Otero,  and  Clark  mines.  Those 
representing  the  Weaver  and  Otero  mines  were  secured  in  connection  with  coal  tests  that 
were  made  in  1904  at  the  Geological  Survey  coal-testing  plant  at  St.  Louis. 
In  the  Weaver  mine  the  samples  were  obtained  from  beds  No.  3  and  No.  3^  by  cuts 
across  the  face  of  the  coal  from  roof  to  floor,  including  everything,  as  the  beds  are  free  from 
partings  of  any  kind.  These  large  samples  were  pulverized  and  quartered  down  to  quart 
size  and  sent  in  sealed  cans  to  the  laboratory  at  St.  Louis.  Analysis  No.  5,  on  page  258, 
represents  the  sample  from  bed  No.  3^,  and  analys's  No.  6  that  from  bed  No.  3. 
Similar  samples  were  taken  from  the  Otero  mine,  every  precaution  being  taken  to  insure 
their  representative  character.  Analysis  No.  7,  on  page  258,  represents  the  sample  from 
the  Crown  Point  bed,  No.  8  that  from  the  Otero  bed,  and  No.  9  that  from  the  Thatcher  bed. 
The  sample  from  the  Clark  mine  was  obtained  during  the  course  of  the  present  work.  It 
was  obtained  by  making  a  cut  across  the  working  face  of  the  coal,  8^  feet  in  thickness,  and 
included  everything  except  two  partings  1  inch  and  3  inches  thick.  This  sample  was 
treated  in  the  usual  manner  and  its  character  is  shown  by  analysis  No.  4,  on  page  258. 
Bull.  285—06 17 
