Figure 25. Market price versus concentration of metal in typical ore
Concentration in ore is the product of estimated crustal abundance (ppm) and estimated ore enrichment factors.
median estimates. Indium concentrations in ore are based on the first, second, and third quartile indium
concentrations used to generate the medium-term primary supply curve.
All prices except those for indium are from Green (2009) and are based on the average monthly prices from January
nium octoxide (84.8% uranium). Price range indicated for indium based on observed prices over a 20-year period.
Our base-point estimate of indium concentration against an average recent market price of
data, we use first quartile, median, and third quartile values of indium concentrations in
economically feasible deposits that form part of our medium-term primary supply curves. First
and third quartile data points are indicated in Figure 27 by the labels InQ
We then overlay the range of indium prices observed over the past 20 years to indicate how
tightly indium may have tracked the line over this period.
Again, we note that even when incorporating a range of potential indium ore concentrations and
highlighting the historical range of indium prices, indium still appears to fit well within the
model and a long-term price of $600–$1,000/kg appears to be supported.
Recognizing that the log-log scale may lead one to conclude a better fit than justified, we use the
results from the simple linear regression described in footnote 40, and plot the ±95% and ±80%
confidence intervals (Figure 27). Given the range of indium’s concentration in ores (165–394
ppm), the 95% confidence intervals reported in Table 20 and displayed in Figure 27 support a
wide price range of $26–$11,262/kg. Instead, examining the 80% confidence intervals yields a
narrower price range of $163–$4,353/kg. The historical prices suggest that indium came close to
the lower 80% confidence interval in 1994. This can also be observed visually in Figure 27.
Because indium is principally produced as a byproduct, while the other minerals included in the
within the lower bounds of the confidence intervals provided. So unless prices induced a change
in indium production from principally byproduct to main product production, we would not
expect indium prices near the upper end of our confidence intervals.
Figure 26. Market price versus concentration of metal in typical ore,
including confidence intervals from linear regression results
Regression statistics: Multiple R 0.915, R
: 0.837; Adj. R
0.828; SE 0.553; N: 20.
Regression equation: log(price) = 4.776 - 0.834*log(concentration)
t-stat (13.89) (-9.62)
s.e (0.344) (0.0867).