1/5 I went and had a look at Oyu Tolgoy after @DanaWhitney59 and @TheWealthMiner started discussing $ETG and #TRQ. Its a very nice deposit, that should print money if it is not all nationalized by Mongolia. The latest 43-101 focuses on the new big Block Cave, which I think

2/5 has been over capitalized. Its a Rolls Royce they're building there, but they can afford it I guess. Personally, I would have gone for something smaller and grown it more on CF, but that's just me. I was looking at the open pit contribution and I noticed that they have

3/5 some pictures showing the various pushbacks of the open pit. A pushback /cut / OP Phase is a term used by mining guys to describe a particular part of the pit that is to be mined, 1st a block of waste to expose a corresponding quantity of ore, rather than just

4/5 mining a lot more waste all round the pit and then mine all the ore afterwards. This would mean more capex burn up-front and no ore (until it was exposed). Easy to say but hard to do in practice - please my previous thread https://bit.ly/38vgZDI  on open pit economics.

5/10 So, with ref. to the 43-101 ( https://bit.ly/3hbxCs2 ) p. 162-165, the first few phases of our Mongolian pit look really sensible. But zooming into the pit on google earth also revealed some interesting challenges they seem to be having.

6/10 Luckily, they have P6b to the north of this pit which requires no waste stripping to mine themselves out of a corner, but this problem will get worse as the cuts get more complex in the next 4 years. Some real-world challenges explained that laptop-planners don't notice:

7/10 Surely they have some good schedulers looking at this but the sequencing of the pushbacks is so important in the short/medium-term. It would be good to see what the planned "photo" of the pit looks like each calendar year. This would be more useful than what is in the 43-101

8/10 Its easy to be critical with only superficial information available, but looking at the table below, the mining sequencing and pushback phasing tells me there is a lot of room to materially improve things. Its almost as if they want the UG mine, & have given up on the OP.

9/10 Additional irksome observations affecting productivity and the smooth operation of any pit below. It tells me the guys really are focused on that BC, and it makes sense as RioT are brilliant at them. The thing is, there is plenty still to be made from the open-

10/10 pit operations. Years ago they were the best @ open pit. Getting it right again could drop the UG capex by a few hundred M$ perhaps even a billion$, and also give the guys more time to optimize & ramp up the UG at a lower cash burn.