266  CONTRIBUTIONS    TO    ECONOMIC    GEOLOGY,  1004.        [bull.  26 J 
New  Jersey. — The  principal  producer  of  the  Eastern  States  is  the 
New  Jersey  Zinc  Company,  operating  mines  at  Franklin  Furnace, 
N.  J.,  and  reduction  works  near  Bethlehem  and  Palmerton,  Pa.  The 
oxide  furnaces  and  smelters  at  Newark  were  dismantled  in  11)04,  the 
policy  of  the  company  being  to  eventually  concentrate  operations  at 
Palmerton.  The  New  Jersey  Zinc  Company  also  owns  the  mines  at 
Sterling  Hill,  near  Ogdensburg,  N.  J.,  which  are  not  worked  at 
present. 
The  two  deposits  mentioned  above  are  notable  for  (a)  the  great 
size  of  the  ore  bodies,  (b)  the  unique  character  of  the  ores,  since  the 
three  principal  zinc-bearing  minerals  are  elsewhere  practically  un- 
known as  ores,  and  (c)  the  difficulties  which  have  been  overcome  in 
dressing  and  reducing  the  ores. 
(a)  The  only  available  data  on  the  size  of  the  ore  body  at  Franklin 
Furnace  are  those  given  by  Mr.  Nason  (1894),  who  estimates  it  as 
equivalent  to  a  prism  3.500  feet  long,  800  feet  wide,  and  25  feet  thick, 
containing  70,000,000  cubic  feet.  In  the  ten  years  intervening  since 
this  estimate  was  made  development  work  has  been  continuous,  so 
that  these  figures  are  in  all  probability  below  the  truth. 
(b)  Though  varying  greatly  in  different  parts  of  the  mine,  a 
current  estimate  of  the  average  mineralogical  composition  of  the  ore 
at  Franklin  Furnace  is  as  follows : 
Average  mineralogical  composition  of  Franklin  furnace  ore. 
Per  cent. 
Franklinite    51. 92 
Willemite  31. 5S 
Calcite    12.67 
Zincite    .52 
Other  silicates  3.31 
Total   100.00 
These  figures  are  calculated  from  the  following  analysis: 
Average  chemical  composition  of  Franklin  Furnace  ore. 
Per  cent. 
Iron  sesquioxide   32.06 
Manganese  protoxide  11.06 
Zinc  oxide 29.35 
Carbonate   of   lime 12.67 
Silicate  and  insoluble  matter ___      14.57 
Total    99.71 
(c)  Prior  to  1840  unsuccessful  attempts  had  been  made  to  use  the 
zinc  and  manganese  bearing  ores  of  New  Jersey  for  iron  manufac- 
ture. In  that  year  portions  of  the  deposit  containing  much  zincite 
were  first  worked  for  zinc  alone,  this  material  being  manufactured 
I 
