Is it still viable?

With the drop in price for tungsten is this mine still viable ?
Correct me if I am wrong as I am using a tungsten price of US25 a kg of ATP and then using a value of 60% of that for tungsten concentrate produced by WLF
5k tpa WO3(opimised) * 1000 * 15 = US$ 75 M
add $7M for Sn credits = $US 82M per annum revenue which seems low if it was the equivalent sized 4Mtpa gold mine even if the strip is 1.5:1 as here .

A 0.15% WO3 grade using the pricing above seems to be worth around $22.50 a ton ( 15000 a ton * 0.015% ) which would equate to less than a 1 gram a ton gold mine (1,100 an oz /31 = $35 ) even if Sn credits are added back
I can not think of any gold mines of this tpa that would be running profitably with a sub 1 gram a ton grade .

Could my pricing for WO3 conc be too low ?