respectively. The value of fY,i ranges from a minimum of 1.0 at R = 0 or 1, to a maximum of ~ 1.15 at R = 0.50. Using a typical value of fY,i = 1.07, the error in the amplification of the yield uncertainty is only 7 %, sufficiently small to neglect in most cases. Similarly, the exact amplification in the uncertainty of the recovery also has a typical value of order 1.07. The inclusion of these expressions allows for the very small effects of the deviation from perfect power law behaviour to be included. However, given these corrections only apply to the amplification, and given the amplification can vary by orders of magnitude, it is reasonable to use the simpler expressions given by Equations 12 and 14. At worst these will give a 15 % over-estimate of the error amplification.