TAM doesn't need to be profitable as an open pit mine (but let's hope that it will be!)12 Sep 2025 18:28
Hi All,
Just back and great to see such a strong day for the share price. Next week is likely to be exciting as well so let's see what happens. I said that I would come up with a few examples of other mines where profitability of secondary mines, per se, wasn't the priority and waste rock to be used in connection with the main mine and/or TSF was. Here are some for your review. Really happy with progress at Solgold. So good to have an excellent management team now. Have a great weekend, all.
Cadia (Newmont)
Main ore body is Cadia East panel cave. Satellite was Cadia Hill open pit. The pit itself was approved for in-pit tailings disposal. Waste rock dumps at site provided the engineered rockfill for the embankments of the Southern and Northern TSFs which are essential for the life of the cave. Rock volumes included more than 266 Mt in the South WRD and more than 30 Mt in the North WRD. First TSF stages were completed in 1998 and 2001 and have since been progressively raised. The open pitβs economics were not the driver. The cave was the engine and the pit waste rock made the tailings system possible.
Northparkes (CMOC)
Main ore bodies are the E48 and E26 block caves. Satellites are small open pits such as E44 and E28NE. Planning documents show waste rock from the new open cuts will be used for tailings facility embankment construction. Additional TSF capacity is explicitly linked to these pits. Rock sources are within 300 metres of haul routes, minimising costs. The cave orebodies are the prize while the open pits provide nearby rock that reduces TSF build costs.
Oyu Tolgoi (Rio Tinto)
Main ore body is the Hugo North underground block cave. Satellite is the Oyut open pit. A downstream raised TSF of about 2 km on each side serves the complex. The open pit started production in 2012 while the cave was under development. Waste segregation is designed so that non acid forming rock from surface works is used for TSF embankment construction and encapsulation. The open pit was never solely about value but rather about rock, haulage and early site infrastructure that enable the caveβs tailings footprint.
Red Chris (Newmont)
Main ore body is a block cave currently under development. The satellite is the existing open pit. The transition plan calls for re-purposing the open pit as a waste and development rock storage facility. The Tailings Impoundment Area uses annual centreline embankment raises built from rockfill shells. The pit provides proximity and capacity for the underground development rock and waste to be used in TSF construction. The main cave will deliver the returns while the open pit is the enabler of tailings and infrastructure.
This shows that in each case the company optimised for rock logistics and TSF geometry rather than the net present value of the satellite pit. The smaller body was an enabler for the cave, not the centre of the economic model. Cascabel and Tandayama follow the same logic but I suspect TAM will be