butts.]  WABBIOB   COAL  BASIN,  ALABAMA.  377 
ings  into  several  thin  benches  of  coal,  so  that  it  probably  could 
not  be  mined  with  profit  under  present  conditions. 
According  to  the  reports  of  Mr.  McCalley,  the  Black  Creek  coal  is 
persistent  in  the  quadrangle.  His  measurements  in  both  the  Little 
and  Big  basins  show  a  thickness  of  from  10  to  54  inches  for  the  seam, 
there  being  in  many  cases  a  clean  bench  of  coal  from  30  to  40  inches 
thick.  If  the  quality  of  the  coal  in  this  quadrangle  is  as  good  as  in 
other  parts  of  the  Warrior  field,  it  would  appear  that  it  could  be 
mined  with  profit  in  some  localities. 
Nothing  very  definite  is  known  about  the  coal  seams  below  the 
Black  Creek  seam.  The  writer  obtained  a  measurement  of  a  seam  25 
inches  thick,. with  clay  partings,  190  feet  below  the  Jefferson  coal  on 
the  little  stream  west  of  Adger,  but  no  indications  of  minable  seams 
at  horizons  certainly  below  the  Black  Creek  seam  were  seen. 
GENERAL  MINING  CONDITIONS. 
The  Brook  wood  group  of  coals  lies  nearly  flat.  Its  outspread  in 
the  quadrangle  is,  however,  small.  The  Gwin  and  Cobb  coals  are  not 
at  present  mined  and  may  not  be  for  a  long  time  to  come.  Mining  in 
the  quadrangle  will  therefore  probably  be  mostly  confined  to  the 
lower  coals  of  the  Pratt  and  Mary  Lee  groups,  which  outcrop  along 
the  margins  of  the  Big  and  Little  basins,  where  the  dips  vary  from 
15°  to  80°.  While  these  coals  lie  nearly  horizontal  throughout  most 
of  the  Big  basin,  they  can  only  be  reached  by  shafting  to  considerable 
depths  or  by  following  them  down  from  their  outcrop.  In  proceed- 
ing by  the  last-mentioned  plan  the  rocks  of  the  vertical  zone,  already 
described,  would  be  encountered  and  such  difficulties  as  they  might 
present  would  have  to  be  reckoned  with.  In  addition  to  being  ver- 
tical or  highly  inclined  with  normal  northwest  dip  the  rocks  of  this 
zone  may  be  locally  overturned  or  affected  with  strike  faults  to  a 
greater  or  less  extent,  and  such  structures  would  be  important  factors 
in  the  mining  problems  to  be  solved. 
The  coal  seams  of  this  field  are  generally  overlain  by  stiff  shale  or 
by  sandstone,  and  these  form  a  roof  that  is  generally  stable,  so  that  a 
minimum  of  propping  is  necessary.  The  most  important  senilis  are, 
with  their  included  partings,  thick  enough  to  give  sufficient  height  to 
the  entries  and  headings  without  removing  any  rock  from  the  roof  or 
floor  of  the  mine.  In  the  case  of  the  Carter  and  Milldale  seams, 
which  are  thin  and  overlain  closely,  in  some  places  immediately, 
by  heavy  sandstone,  it  is  necessary  to  remove  much  rock  from  the 
roof.  Where  sandstone  immediately  overlies  the  coal  its  removal 
adds  considerably  to  the  expense  of  mining,  though  the  sandstone 
makes  a  good  roof.  In  either  of  the  above  cases  there  is  always  ;i 
large  quantity  of  waste  material  to  be  disposed  of,  ami  its  disposal 
often  involves  considerable  difficulty  and  expense, 
