418  CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,    1907,    PART   II. 
covered  with  a  coating  of  coal  dust,  which  adheres  so  strongly  to  the  agate  surface 
that  it  is  removed  with  difficulty.  With  other  coals  there  will  be  only  a  thin  film  of 
coal  dust  adhering  to  the  mortar  and  pestle,  while  with  still  others  both  mortar  and 
pestle  will  be  nearly  as  clean  after  the  coal  is  pulverized  as  they  were  before  the  oper- 
ation began.  *  *  *  The  degree  of  adhesion  seems  to  coincide  with  the  coking 
qualities  of  the  coal.  If  it  adheres  strongly  the  coal  will  probably  make  excellent 
coke;  if  it  adheres  only  slightly  the  coal  possesses  the  coking  qualities  to  only  a  slight 
extent,  if  at  all;  and  if  the  mortar  shows  no  coating  of  dust  the  coal  is  to  be  regarded 
as  noncoking. 
DEVELOPMENT. 
Coal  has  been  mined  from  small  banks  in  this  district  for  many 
years  to  supply  a  small  local  demand.  The  heavily  forested  condi- 
tion of  the  region  makes  wood  so  cheap  and  easy  to  obtain  that 
there  was  little  incentive  on  the  part  of  the  native  population  to 
develop  coal  for  domestic  fuel.  With  the  building  of  the  Louisville 
and  Nashville  Railroad  and  other  lines  into  this  district  increased 
interest  was  shown  in  the  coal  beds  and  considerable  prospecting  was 
done. 
The  following  companies  are  operating  or  are  preparing  to  operate 
in  the  near  future:  Virginia  Lee  Company,  Dominion  Coal  Com- 
pany, Black  Mountain  Mining  Company,  Lee  Coal  Company,  Darby 
Coal  and  Coke  Company,  Bondurant  Coal  Company,  Monarch  Coal 
and  Coke  Company,  Black  Mountain  Collieries  Company,  and  Vir- 
ginia Iron,  Coal,  and  Coke  Company. 
