GRADE AND TONNAGE MODEL OF OOLITIC IRONSTONES
By Greta J. Orris
COMMENTS
As with many deposit models, grade-tonnage information was not available
for some of the well-known deposits. In addition, deposit definition (especially
with regard to size information) is complicated by (1) the areally extensive
bedded nature of the deposits, (2) the presence of multiple mineralized
layers interbedded with country rock, and (3) the ambiguity of the reporting
with regard to mining district or individual mine- or deposit-level information.
Some deposits and (or) mines had tonnages or grades that were so disparate
from the tentative grade-tonnage models that they could not be considered.
This type of problem is often due to reporting error or deposit definition
error. Several tonnages reported for English deposits were orders of magnitude
too low and might represent reserves of mines working only parts of larger
deposits, and some U.S. and French deposits had tonnages so large that
it is likely that several deposits were composited into single grade and
tonnage figures. Lastly, it is impossible to claim that all possible sources
of information were found and consulted. See appendix
B for locality abbreviations. See introduction
for explanation of the grade and tonnage model as shown in figures 25-28.
Figure 25. Tonnages of oolitic ironstone
deposits.
Figure 26. Iron grades of oolitic ironstone
deposits.
Figure 27. Silica grades of oolitic ironstone
deposits.
Figure 28. Phosphate grades of oolitic
ironstone deposits.
DEPOSITS
DEPOSITS
Name
Country
Name
Country
Ait
Amar MRCO
Langrial
PKTN
Aswan
EGPT
Ljubija
YUGO
Birmingham
USAL
Ma-yu-kou
CINA
Boulhaut
MRCO
Moncorvo
PORT
Camdag
TRKY
Musson-Halanzy
BLGM
Cho-lu
CINA
Nucice
CZCL
Cleveland
UKEN
Nurra
ITLY
Couthuin
BLGM
Ouarzemine
MRCO
Demir
Hisar YUGO
Pang-chia-pu
CINA
Frodingham-
Scunthorpe
UKEN
Paz
del Rio CLBA
Gara
Djebilet-
Central
area ALGR
Salzgitter
GRMY
Gara
Djebilet-
East
area ALGR
San-cha-kou
CINA
Gara
Djebilet-
West
area ALGR
Settat
MRCO
Holoubkha
CZCL
Sierra
Grande AGTN
Hsin-yao
CINA
Sui-Ning
CINA
Imi
n'Tourza MRCO
Sumadija
YUGO
Isle
of Raasay UKSC
Tajmiste
YUGO
Jebel
Ank TUNS
Wabana
CNNF
Kerch
USSR
Yen-tung-shan
CINA
L'Hermitage-
Lorge
FRNC
Zditz
CZCL