Neil Ringdahl Profile picture
Aug 20, 2019 26 tweets 9 min read Read on X
1/25 A REVIEW OF $ADT 's RUPICE: Its a good polymetallic exploration project v. likely to go into production, hence the interest. I built a "basic" model after the Co. provided me with some DDH survey info - Tx again @croninpd. All Other info came from bit.ly/33JthFl
2/25 I should add this is my desktop opinion. I am:
-Not being paid by ADT
-Not a S/H and may/may not be one at some point.
-Don't know the people.
-Have not discussed this with them.
-Have not visited the project
-Doing this because its what I do when I don't ride dirt bikes.
3/25. Some have said the biggest risk is the jurisdiction. It so HG that nothing could possibly go wrong! I don't know. I think the biggest risk could be wild optimism. The drilling results are great, but infectious & THAT bias could lead to some costly decisions. Besides-Murphy.
4/25 Its about 45km from Sarajevo as the crow flies. 77km by good road to the old Tiscovi (Veovaca) plant site (or 44km on a small, tight mountain rd). I would imagine a power line as-long would need to be constructed. Its in a very mountainous but historical mining area.
5/25 By all accounts the community is supportive. There is need for work. Permitting seems well managed, in order & not unduly onerous. ADT seems to have good people managing this. But where would the plant & TSF go? The mountains are big & rough.
6/25 Most of the drill assay data came from the prospectus & Co. news. What a mess to sort out. Columns in different orders, different significant figures used, inconsistent & incomplete info presented. Its worrying: Could they have been sloppy with the sample prep and ....
7/25 ...QA/QC? Its possible, one would hope not! Geological (litho) envelopes were not used in the creation of the block model, rather grade envelopes were used, 2 for each element, one for HG & another for LG. I don't like this but when creating my own pseudo solid of the...
8/25 ore zone based on an AuEq cut-off I came up a similar volume to that reported in the Resource. Pleasing. The ore body appears highly faulted and experience & core loss in places would suggest the geotechnical conditions in & around the high grade areas could be very poor.
9/25 The ore body out crops at the top of the mountain and dips 37-50º in a sub-parallel direction to the North West, under the North-facing slope. This would be favorable for an open-pit scenario, but for the fact of the offset plunge increases the stripping ratio quickly.
10/25 OP mining this deposit has the disadvantage of starting in the outcrop at the top, where most of the Inf. material lies. It is also lower-grade than the rest below, maybe lower recovery also, so has a lower initial revenue/year. I did not have time to do a pit optimization.
11/25 However in OP mining ~80% of the resource, I estimated an approximate SR of ~1:15 using 45º slopes for 122Mt waste & 8Mt ore. It probably would be mined in 3 push backs (Cuts), but I spreadsheet-scheduled just 2. These No.'s are very rough & are order-of-magnitude only.
12/25 Spinning the thing around in 3D with a pseudo-estimated topography scaled off from GE, I came up with a more logical UG layout, adopting 3 main portals down the side of the mountain for a total of about 5,400m of primary waste development. The lowest portal comes out near
13/25 the base of the mountain and close to a road linking back to Veovaca, where the plant might be located. Why so far away? Simply b/c there was a plant there before, permitting would be easier & construction costs lower (flat ground). A study need to be done on plant location
14/25 Given there are around 7.5Mt in Indicated Resources, 1Mt/yr would be considered a reasonable production rate. A plant ought to be built with a 3,000 tpd line and a crushing circuit for double that volume if $ADT is bullish on the exploration upside, otherwise not.
15/25 The reason for this is that in the event the mine resource grows another line can be relatively inexpensively installed later on, giving 2Mt/yr capacity. Rather start smaller on lower Capex & lower expectations all round & grow on CF. Promoters don't like this. Go figure.
16/25 A simple schedule for the UG and OP scenarios would give us a glimpse of a possible project value. You may have already noted the lower recovery assumptions used for NSR. That's because it until the test work demonstrates otherwise, why be wildly optimistic!?
17/25 Then we have barite. ADT use $200/t. I have others telling me as low as $50/t. Its used mostly in oil drilling but I have my doubts there will be market for 270kt/yr !? Anyways if we cant get ALL the lead out of it will it even meet EU/intl. safety guidelines as a product?
18/25 BaSO4 is an industrial mineral that has its won idiosyncrasies and a niche market. So no, wild optimism; let's agree to set it aside as an opportunity to improve project economics at some point. Besides using ADT assumptions, it represents only about 14% of the NSR.
19/25 Using market-related payable metal & reasonably conservative TC/RC's, penalties, transport costs, my recoveries, spot prices, and a mining dilution of 15%, I came up with a diluted NSR of around $263/t on the Indicated resource. Not bad, actually pretty good!
20/25 So the mine plan assumes 7.5Mt diluted down to 8.5Mt with 15% reduced grade because I have assumed v. poor ground conditions in such good ore. UG site costs come in around $55/t over the LoM. Capex 128MM.
21/25 Here are the bottom line pre-tax, pre-royalty numbers (of which I have no idea).

NPV8% comes in at $907M which I know is lower than most other estimates, but why build unrealistic expectations? Projects seldom come in on time, on budget and do as well as we would like.
22/25 Funding required is $136M including W/C but excludes permitting, exploration, test work & engineering.
Remember though, this is a very quick desktop estimate.

The OP scenario obviously comes in at a lower Opex ($20/t).
23/25 The OP Scenario has ~$50M more in additional Capex. The LG Inferred material which has to be mined 1st (& was excluded from the UG model) has a big negative impact lowering NPV8% by ~$200M on this alone (using the same LoM throughput), even when considering the much lower
24/25 mining dilution for OP. The undiluted NSR of the Inferred material is almost 50% that of the Indicated, and then there are the additional terrain & environmental permitting challenges for OP as well. I would take the higher Opex UG mining any day.
25/25 In summary then $ADT does indeed look very attractive, 💯 even using conservative assumptions. I'll leave it up to the rest of you to decide what the SP should be. All the best to Paul, the team and Sandfire in this venture. I'll be watching with great interest. 👍

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More from @NeilRingdahl

Nov 29, 2022
Good tactical & strategic planning along with execution is more important than grade. A 🧵

Our case study today is Pure Gold $PGM
& how it turned into Pure ..💩

1st, some theory you'll know if you have been following me 4 a while:
/1
These concepts are important because the decision was to use large trackless machines in the mining of the new access ramp & therefore say to say all ore development will be of a similar size as well. We should therefore expect dilution issues in narrower orebodies of Marsden /2
SRK (Vancouver) did quite a nice MRE for the Co. I know Wayne Barnett, he is quite a smart fellow & a good geo with solid experience. The report reads well, and tellingly, there are NO RESERVES & NO MINE PLAN. Alarm🔔's beginning to ring. /3
Read 13 tweets
Nov 23, 2022
#Mining with Electric machines: A modern miracle to save the environment or a pipe dream? 🧵
I'll discuss both open pit & underground apps.
For 60yrs, engineers have been innovating electric mining machines b/c they're cheaper. An electric dragline moves 60t each swing.😳1/
These monsters are so huge, a ship's diesel engines don't cut it. Way before I was even born, the clever guys worked out its cheaper -on a per-tonne basis- to use electric motors connected to the grid. They work well and are excellent in soft-rock stripping operations. 2/
Mining is about LOGISTICS of moving large masses of material to expose what is valuable & then move the valuable material to extract the metal. All this movement requires a LOT of energy.👇If you have ever dug your own swimming pool, you understand.😏 3/
Read 20 tweets
Oct 23, 2022
The DANGERS of spreadsheet mining. A🧵

Some of you may have been following the $AUN debacle, a good e.g. when the Lassonde curve goes south. 😬

I will discuss a few important technical flaws in the Aurcana investment thesis. /1
A couple of things in the 2022 Feasibility study Mineral Reserve Estimate immediately jump out.
1- The reserve is small
2- The min. mining width is crazy
3- The dilution No.'s seem too precise

One thing mining is not is precise. It can be accurate, but that's a different thing/2
Let's learn all about this mining method from $AUN. Below are excerpts from the FS tech report with my comments in red.
A (nice) investor video of the mine explains the resue method quite well by the then COO during minutes 16:41-23:33.

/3
Read 11 tweets
Aug 25, 2022
1/ Lets review this Q:
@Darken_Man got it right, well done.
Look at the pit floor: Very uneven, by far the biggest negative impact on this operation. Why? Slower reversing in, slower truck tramming, more difficult loading & damage to tyres. "How so?", you may ask.
Thread:
2/ Have you ever driven a car on a really bad road? Its slow and hurts the car. With trucks its way, way worse b/c trucks are the most expensive part of the open pit mining biz. & they're also the production conveyor that moves your product in diluted form to the plant.
3/ Consider a typical medium-sized OP operation with 180t dump trucks running an avg. cycle of 45 minutes, for 19 effective hrs/day. That works out to 1.64 million tonnes per truck per yr (with 5days off). Now, if the floor was level it would likely save 20-40 seconds reversing; Image
Read 15 tweets
May 17, 2022
1) Thread: From Drilling to Open Pit Optimization For Dummies.
Imagine you have project and hire a truly great geologist who has drilled some fantastic looking sections based on a small surface anomaly he found from a surface geochem sampling program. Image
2) Your geologist (lets call him George) tells you its a pipe-like copper skarn, vertical in nature about 50m wide and open at depth that he interprets (a key word here) in section in this pic below. (We will keep things simple by staying in only two dimensions X & Y). Image
3) Your drill results come back and your copper values are amazing. The consultants concur with George's interp, and then create a 3D grid over of blocks over it, each block being approximately equal to a the minimum mining unit size, which for open pit would be about 10x10x10m. Image
Read 19 tweets
Mar 28, 2022
1/11 $REG REVIEW Thread: - I'm a hopeful shareholder, underwater🙄for 3yrs now. Bought it at 1.65 - yeah crazy I know. Here's a review & why I'm still in. The pic below says it in 1000 words.
2/11 Probably the most important point is the property is and in particular the resource is part and the same of an adjacent operating mine, Tantahuatay, which is 40.1% owned by Buenaventura (the operators), 44.2% by Southern Copper & 15.7% by Regal Ware Inc. out of the USA.
3/11 Tantahuatay is a sweet oxide OP mine hitting the oxide cap above a huge porphyry & produced 110koz Au & 2.1Moz Ag last year. However this year production is F/casted to be 77koz Au as they start to get into the sulphides which cannot yet be processed.
Read 11 tweets

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