CPC Eng LS Pilot Plant design

Since the CPC Engineering design for the Large-Scale Pilot Plant is due to be released in about four weeks, I thought I would answer two questions to help clarify some issues.
a) How many tonnes of 6% spodumene concentrate are required to produce 2500 tonnes of lithium carbonate?
Spodumene contains 8.03% Li2O, Ref A. Mined ore has a lower content because of impurities. Ore may be concentrated to increase the percentage of Li2O. One tonne of 6% spodumene concentrate contains  0.06 tonne of Li2O.
From the atomic masses of lithium, 6.941, and oxygen, 12, (see table below) we can deduce that Li2O contains a fraction 2x6.941/(2x6.941+12)=13.882/25.882=0.5383 of Lithium. So, one tonne of 6% spodumene concentrate contains 0.5383*0.06=0.032298 tonnes of lithium
Using a similar argument Li2CO3 contains 18.79% lithium by weight, so 2500 tonnes of lithium carbonate contains 0.1897*2500=469.75 tonnes of lithium.
To produce 2500 tonnes of lithium carbonate we need 469.75 tonnes of lithium. To get this we need to process 469.75/0.032298=14544.24 tonnes of 6% spodumene concentrate.
b) What price can 2500 tonnes of lithium carbonate be sold for?
The selling price of lithium carbonate is US$(10000 -16000) per tonne for a contract and from US$18000 to US$21000 per tonne spot price, Ref B.
So, 14544.24 tonnes of 6% spodumene concentrate will produce 2500 tonnes of lithium carbonate, which can be sold for US$(25-40) million on a long-term contract or between US$ (45-52.5) million on spot sales.
Note: 14544.24 tonnes of 6% spodumene concentrate could be sold (using GXY prices) for about US$900/t i.e. US$13 million. One month’s production of 6% spodumene concentrate from Mt Cattlin could supply the large-scale pilot plant for the first year.
Ref A: http://webmineral.com/data/Spodumene.shtml#.WRgqFoVOJjo
RefB: https://seekingalpha.com/article/4050011-lithium-miner-news-month-february-2017
‘Intelligence recently reported February 2017 China LCE spot prices at $18-21/kg, and contract prices ranging between $10-16/kg. Joe Lowry's recent reports from Japan were, "lithium carbonate prices up to $15/kg." SQM reported in Q3 2016 they are achieving lithium carbonate contract prices at US$12,000/tonne.’
Atomic mass table
Atomic number Atomic weight   Atomic mass
Li 3   6   6.941
C 6   12    12
O 8   16    15.99