In the 1976 report the figures for pegmatite reserves and resources represented in situ tonnages reduced by 75% for open-pittable deposits and 50% for probably underground operations.  The Panel estimated that these deductions were sufficiently large to cover all mining, concentrating and chemical processing losses.  These sources are indicated by an asterisk in Table I.

In this paper all other tonnages are in situ tonnages.

For other pegmatites the deductions should be comparable but for brines the recoveries will vary considerably.  In the case of continental brines initially processed by solar concentration and involving precipitation of salts such as sodium chloride and potassium chloride the initial ‘loss’ of brine entrained in the precipitated salt is substantial.  However, this is not a permanent loss.  The chemistry and nature of the precipitated salts varies with the brine feed so the losses will vary at different operations.  At the Salar de Hombre Muerto in Argentina there are no entrainment losses.

Losses associated with the potential recovery of lithium from geothermal and oilfield brines and from hectorites are not known yet.

Regarding production costs, evidence indicates that those at the Salar de Atacama are the lowest and that brines with a high magnesium content will incur higher costs.  Pegmatites, based on the abandonment of North Carolina are obviously a more expensive source  but with lithium carbonate prices now double those that were current when the North American producers moved south, Chinese producers may not have to abandon their pegmatite sources as a result of being uneconomic.  Two non-Chinese companies are considering production from spodumene.

Costs from geothermal brines, oilfield brines and hectorities have not yet been determined.

The tonnages listed are large but they don’t represent the total lithium that may become available.  Few, if any, known pegmatites have been fully explored, more remain to be discovered.   Only one oilfield brine is included in the total, only one geothermal brine and only one hectorite deposit is included.