Small Scale Tailings Production2 Apr 2021 19:08
It is worth pointing out that modern day open pit operations are considered high grade at 1.5g/t and we have a variety of figures given from various RNSs that are comfortably above that figure. We also know that the historic mines that were 'worked out' 80-100 years ago were all shallow, exceptionally high grade gold and silver, but extracted with relatively low-tech panning and/or sluicing methods.
Tailings grades and volumes:
(1) MJ Tailings = 12kt at 2.28g/t gold and 658g/t silver Ref: RNS @15-Oct-20 & current licence to extract 900t
Note: Sampling of veins in former workings returned high grade gold samples including 19.1 g/t, 27.4 g/t & 95.6 g/t Au Ref: Mar-20 company presentation
(2) Olympic Tailings = 41kt at 1.67g/t gold Ref: Sept-20 company presentation, subject to licence $135k balance paid
Note: Olympic mine produced 35kt ore grading at average 25g/t gold (28Koz)and 658g/t silver (740Koz) for 39k GEO overall. No tailing grade quoted for silver content although likely there will be 32g/t minimum assuming similar 5% of head grade
(very) Basic Cost/Profit Modelling:
MJ Gold = (12Kt ore x 2.38g/t x 50%)/31.1 = 460oz x (1750-1350) = $184k or £133k profit (revenue = £585k)
MJ Silver = (12Kt ore x 658g/t x 40%)/31.1 = 102Koz x (25-0) = $2.55m or £1.85m profit (revenue = £1.85m)
MJ Summary: Costs = £450k & Revenue = £2.42m & Profit = £1.97m
Oly Gold = (41Kt ore x 1.67g/t x 50%)/31.1 = 1,100oz x (1750-1350) = $440k or £320k profit (revenue = £1.4m)
Oly Silver = (41Kt ore x 32g/t x 40%)/31.1 = 16.8Koz x (25-0) = $420k or £305k profit (revenue = £305k)
Oly Summary: Costs = £1.08m & Revenue = £1.705m & Profit = £625k
Assumptions:
Gravity processing recovery: Gold = 50% & Silver = 40% Ref: RNS 1-April-21, expect higher %gold but no info!
Metal prices: Gold = $1750/oz & Silver = $25/oz
Costs: AISC of $1350/oz on gold production only as very small scale, but offset by ore readily accessible at surface & no real mining required
Plant: would need to be sized to ensure adequate throughput and additional gravity separators could be added to boost %recoveries
I've made some basic assumptions and lumped cost into a variable ASIC figure that I applied to the gold recovery only and could be used to cover both OPEX and CAPEX repayments over time by including both MJ and Olympic tailings. Costs massively predicated on equipment sizing, throughput & %recovery expected as relatively modest % increase may pay for itself quite quickly depending on throughput and tailings grade. Once setup and running could be used to process primary ore mined from GWMO licences.
I'm no mining engineer, but was expecting to see higher gold %recoveries, but like anything it depends on complexity of gravity processing used and cost/benefit. A 10% increase in gold & silver recovery would give an extra FCF of £490k for MJ and £140k for Olympic using above model to set as profit and/or paydown higher spec plant costs.
AIMHO & DYOR