CLINTON    ORES    OF    BIRMINGHAM    DISTRICT,   ALABAMA.  151 
pany  at  Trussville  and  that  of  the  Central  Iron  and  Coal  Company 
at  Holt,  near  Tuscaloosa. 
In  general,  the  furnaces  run  on  a  burden  of  coke,  red  ore,  brown 
ore,  and  dolomite  or  limestone,  though  certain  of  them  at  times  use 
only  a  self-fluxing  red  ore.  The  ores  of  the  district  contain  too  much 
phosphorus  (see  analysis,  p.  135)  to  be  converted  into  steel  by  the 
Bessemer  process,  but  such  pig  irons  are  being  very  successfully  used 
for  basic  open-hearth  steel  making.  The  open-hearth  process  is 
employed  by  the  Tennessee  Coal,  Iron  and  Railroad  Company  at 
the  Ensley  rail  mill,  which  consists  of  ten  50-ton  basic  Wellman  tilt- 
ing furnaces  and  one  stationary  furnace.  The  entire  output  of  the 
company's  six  coke  furnaces  is  transferred  as  hot  metal  to  the  steel 
mill,  where  it  is  made  into  billets  and  rails.  The  use  of  the  open- 
hearth  process  as  applied  to  southern  ores  has  passed  beyond  the 
experimental  stage.  The  capacity  of  the  Ensley  mill  is  about  to  be 
doubled  and  other  steel  mills  will  doubtless  soon  be  built  in  the  dis- 
trict, so  that  a  local  market  is  rapidly  arising  for  southern  pig. 
