mmons.]  INVESTIGATION    OF    METALLIFEROUS    ORES,  21 
greatest  possible  scientific  accuracy.  But  since  this  is  an  evident 
impossibility,  their  only  safe  course  is  to  state  nothing  in  the  way 
>f  prophecy  that  is  not  most  amply  justified  in  the  investigations 
lready  completed,  and  to  give  their  grounds  in  full,  that  any  other 
worker  may  use  the  same  facts  to  make  a  more  daring  prophecy  if 
Le  sees  fit.  In  the  present  case  the  promises  as  to  the  future  of  the 
Cripple  Creek  district,  which  may  be  gathered  by  those  who  are 
ompetent  to  interpret  the  facts  presented,  seems  sufficiently  brilliant 
o  satisfy  the  most  captious.  During  the  years  that  immediately 
>receded  this  study  a  number  of  mining  engineers  of  good  standing, 
pho  had  occasion  to  explore  different  parts  of  the  district,  had 
nought  to  find  evidence  of  considerable  secondary  enrichment  in 
he  ore  deposits  thus  far  opened.  This  meant,  if  proved  true  of 
he  whole  district,  that  within  a  definite  time  its  ore  deposits  will  be 
ound  to  be  of  increasingly  lower  grade  as  exploitation  reaches 
eeper  levels,  and  that  it  is  only  a  question  of  time  when  the  ore 
7ill  probably  become  of  too  low  grade  to  work  at  a  profit.  The 
resent  careful  study,  with  far  greater  facilities  than  are  available 
3  any  private  individual,  have  removed  this  menace  to  the  pros- 
erity  of  the  camp  by  showing  that  there  is  no  evidence  of  secondary 
nrichment . ;  whence  it  may  be  concluded  that  there  are  as  rich  ore 
odies  in  depth  as  any  that  have  yet  been  discovered. 
The  next  question  is,  In  what  quantity  are  the  ores  likely  to  be 
ound?  In  respect  to  this,  science  has  yet  discovered  no  method  of 
orecasting  the  future  similar  to  the  secondary  enrichment  theory. 
l11  that  can  be  done  is  to  study  with  great  care  the  ground  already 
pened,  and,  by  observing  the  relative  quantity  of  ore  discovered  in 
le  upper  and  lower  parts  of  that  ground,  to  reason  by  analogy  as 
H  what  relations  of  quantity  the  still  deeper  and  unexplored  parts 
rill  bear  to  those  already  opened.  Into  this  question  there  enter 
prtain  factors  bearing  on  the  probability  of  the  development  of  new 
re  bodies  that  have  nothing  to  do  with  their  actual  quantity.  These 
re  the  increase  in  expense  of  working  with  increase  of  depth 
nd  the  difficulty  of  handling  water  in  parts  not  drained  by  some 
innel,  as  the  deepest  workings  get  a  large  part  of  the  water  from 
11  of  the  surrounding  regions.  Taking  these  factors  into  consid- 
eration, the  authors,  while  admitting  the  possibility  that  the  stronger 
jssures  will  carry  ore  to  far  greater  depths  than  have  yet  been 
pained,  think  it  "unlikely  that  the  zone  between  the  1,000  and 
(000  foot  level  will  yield  as  much  as  the  zone  between  the  surface 
hd  the  1,000-foot  level.'1  Hence  they  conclude  that  in  the  future, 
pile  "  new  ore  bodies  will  undoubtedly  be  discovered  from  time 
)  time  and  individual  mines  may  be  profitable — even  more  profitable 
lan  in  the  past" — the  production  of  the  district  as  a  whole  has 
cached  its  zenith  and  will  slowlv  decline. 
