total mineral reserve valuet = Vt =
[ß pt - ß at - Kt/Rt]* Rt
additionst = [ß pt - ß at - Zt/At]* At
depletionst = [pt - at - rKt/qt - Dt/qt -
rVt/qt]* qt
where ß is an empirically estimated adjustment coefficient with a value between zero and one, and all other variables are as defined in Boxes 3–3 and 3–6.