West Dome Underground - Raising Telfer's production to 650koz

Ive been thinking about the impact of 20th Feb the WEST DOME DEEPS RNS - And Shans recent comments you have to consider Havieeron and Telfer running togther in Tandem in the FY25 analyst call avail here -

First it was necessary calculate a 'back of the envelope' resource, based what we know about the WDD discovery which Is broadly illustrated in this picture and the drilling competed in November. I decided to take look at the potential impact of the west dome underground to Telfer's overall output.

I have concluded the West dome Undergound Will have a material effect on the Greatland's output costs and profitability/.

The Lower Limy Unit illustrated here in Fig 11 It's is the obvious initial starter target. Albeit the west dome is likely to be a full repeat of the main dome underground given the presence of this absolutely key Lower Limy Unit.

We know the mineralisation model is quite reliable, regarding the LLU. The histor of the LLU's excellent performance in the Main dome Underground is well documented.

From fig 11 It's possible to get an approximate rock-ore volume from this drawing as 360m x 700m x 20m = 5,040,000m3. Telfer ores have a specific gravity of 2.6 to 2.7 so that = 13.1Mt to 13.6 MT . Calculating the average grade from these 11 holes (below) I get roughly 4.9g/t. The west dome deeps underground news releases here ; https://polaris.brighterir.com/public/greatland_gold/news/rns/story/x56qd0r




Greatlands own release of Feb 20 "West dome underground project" gives a 'weighted average' grade of 4.23g/t AuEq1 from 16 of the 19 holes that hit gold. Therefore, the contained metal would be broadly 4.23 x 13.3mt / 31.2 = 1.809 Moz of gold equivalent. Realistically only 85% - 88% of this would be ecumenically recoverable... so circa 1.54 to 1.6moz.

Consequently If Telfer produced ore only form this LLU it would take production of 350koz for 4.6 years to deplete that a single unit.

Now this is where it get interesting. The West Dome Underground was formed in the same pulse of mineralisation as the West Dome open pit. That means the metallurgy is identicial, it's just much higher gold and copper grade in this particular unit. Consequently it will blend easily with West Dome open pit, and main dome open pit material which means a higher grade feed can be used to augment the lower grade open pit material processed in the mill.

The WDU grade is so high, Greatland could certainly augment the West Dome open pit 0.65g/t material with 4.23g/t material from WDU to make a 1g/t Telfer head grade blend (or potentially even a bit higher... see below)

The ratios could for example be 9Mt West dome open pit at 0.64 g/t blended with 1Mt at 4.23g producing a weighted average head grade 0.999g/t.
10Mt at 0.999g/t is something like 273koz PA from 1 Telfer train.

We know from the most recent quarterly that present underground mining rates for the main dome u/g are 1.2mt. So if we added that we get a weighted average head grade of 1.08 g/t a single Telfer 10mt train could in principle produce 307koz Au equivalent per annum.

If shaun day can up the underground mining productivity rates to circa 1.5Mt (the hoist is under-utilised at 6mt so shouldn't be an issue) then a single train could in principle receive a head grade at 1.18 g/t which is equates to about 322 koz PA after metallurgical losses



We know from historic records that Telfer's max production years were in 2010-2012 producing some 600-650koz (or 325kox from each ore train).
You can see from the quarterly operations report (*below) Greatland's steady improvements in underground mining rates. For example the executed a improvement increasing from March Q (278 kt) to June Q (298kt by 7%

Essentially It would require a further 25% increase from June Q to achieve a 1.5Mt mining rate, from the underground delivering 322koz from 1 train. Nit unimaginable.

If we have 13mt resources/reserve of lower limy unit that's approximately 8-9 years of mine life producing at 1.5Mt from 1 train ( just 4.5 years production running both 1 and 2 trains). Obviously that would require 3mt PA from the underground which is blatantly a huge step change for the present numbers (1.2Mt) but as you can see not impossibble, either, given a suitable mining plan.

I suspect Macquarie's analysts will probably all over this like a wet flannel and will have no doubt done all the relevant sums.

Naturally a significant increase in Telfers head grade would have a material downward effect on the AISC (given the exceptionally large milling capacity).

Higher grade means, more gold at lower cost.