CLINTON    ORES    OF    BIRMINGHAM    DISTRICT,   ALABAMA.  147 
V-shaped  ravines  at  intervals  of  one-half  to  three-fourths  of  a  mile, 
and  on  both  sides  of  many  of  these  hollows  the  two  seams  are  exposed 
from  the  crest  to  the  foot  of  the  ridge.  Inclined  tramways  are  built 
on  the  flanks  of  the  ravine,  and  when  the  outcropping  ore  has  been 
surface  worked  entries  are  driven  in  on  the  strike  of  the  ore  beds  from 
each  side  of  the  ravine  and  the  ore  is  mined  from  upsets.  A  cable 
tramway  may  be  operated  by  gravity  or  by  power,  depending  on  the 
side  of  the  mountain  on  which  the  ore  is  to  be  delivered.  At  the 
Sloss-Sheffield  Ruffner  mine  No.  1  the  tracks  of  the  railway  which 
transports  the  ore  to  the  furnaces  are  on  the  southeast  side  of  the 
mountain,  making  it  possible  for  cars  loaded  with  ore  going  down  the 
mountain  to  pull  up  the  empties,  but  at  the  Valley  View  mine  of  the 
Birmingham  Ore  and  Mining  Company  the  ore  is  hauled  up  over  the 
mountain  and  loaded  into  railroad  cars  on  the  opposite  side.  At 
mines  of  this  type  soft,  semihard,  and  hard  ores  are  obtained,  depend- 
ing on  the  thickness  and  character  of  the  cover  of  the  seam. 
The  third  stage  of  mining,  the  one  to  which  the  majority  of  the 
workings  in  the  Birmingham  district  have  now  attained,  involves  sys- 
tematic underground  work  entirely.  The  general  plan  is  very  simple, 
Comprising  a  main  or  central  slope,  driven  on  the  dip,  from  which 
right  and  left  entries  are  turned  off  at  regular  intervals  of  GO  to  70 
feet.  The  ore,  which  is  mainly  hard,  is  mined  from  the  upper  side  of 
the  entry,  about  30  feet  being  left  between  the  entries  until  robbing 
is  begun.  Mules  haul  the  trams  to  the  mouths  of  the  entries,  whence 
the  ore  is  moved  up  the  slope  by  cable  to  a  tipple,  below  which  it  is 
crushed  and  loaded  directly  into  cars  bound  for  the  furnace.  A  man- 
way  is  usually  provided  at  one  side  of  the  slope  for  safety.  Compara- 
tively little  water  is  encountered  even  in  the  deepest  workings  of  this 
type,  so  that  a  3  to  4  inch  pump  usually  suffices  to  drain  the  mine. 
A  fourth  stage,  which  some  of  the  workings  may  reach  in  the  near 
future,  will  likely  be  shaft  mining  in  the  basin  east  of  Red  Mountain. 
The  working  face  of  the  ore  bed  can  be  reached  more  directly  by  a  ver- 
tical shaft  300  to  500  feet  in  depth  than  by  a  slope  five  or  six  times  that 
length. 
Mining  conditions  at  present  are  doubtless  at  their  most  favorable 
stage.  The  mining  companies  are  making  an  effort  to  utilize  all  the 
labor  available  to  increase  the  output  of  ore.  In  the  summer  of  1906 
there  were  no  less  than  33  mines  actively  producing  red  ore  in  the  dis- 
trict, besides  seven  or  eight  workings  which  have  been  inactive  since 
the  soft  ore  was  exhausted  from  them.  Of  the  33  mines  in  operation 
30  are  on  Red  Mountain,  within  a  distance  of  about  25  miles  between 
Pilot  Knob  on  the  northeast  and  Sparks  Gap  on  the  southwest.  In 
places  in  the  middle  of  the  district  the  underground  workings  are  prac- 
tically continuous  for  3  or  4  miles,  and  the  old  surface  workings  on  the 
outcrop  of  the  ore  may  be  traced  without  break  for  15  miles  or  more. 
