There are numerous reasons why a process plant may miss
recovery targets. Gold can be more encapsulated in insoluble material, other elements
can consume important reagents -limiting availability for gold-, and sometimes
the ore is characterized as “Preg Robbing.” Refractory ore is an issue and has
been for a while. Notable mines with refractory ore are Prestea, Tarkwa, and
What does this mean?
Sometime ores contain carbon. This carbon absorbs gold
particles which would have otherwise been absorbed onto the “reagent” carbon.
In “The Chemistry of Gold Extraction,” that author states that as little as
0.1% carbon may produce preg-robbing properties.
Carbonaceous ores can be separated into two categories:
mildly and highly carbonaceous.
Mildly Carbonaceous: contain small quantities of
organic carbon, typically less than 1%.
Highly Carbonaceous: contain carbon >1% and
contains carbon that has a strong gold absorbing tendency. This material can
reduce gold recoveries to below 80%.
Ways to deal with preg-robbing:
Use a CIL
process rather than CIP: a carbon in leach flowsheet completes the leach
and absorption process in the same location simultaneously. In completing this
process simultaneously, there is less time for the organic carbon to absorb the
hydrocarbons can passivate the
surface of carbon, decreasing the propensity to absorb gold.
Treatment: Aqueous solutions of chlorine have strong oxidizing
capabilities. It’s not well understood why this process works. Between a pH of 3
and 5 hypochlorous species are predominant and are thought to passivate the
Roasting: Burn it off!
John O.Marsden, I. H. (n.d.). The Chemistry of
Gold Extraction. SME.
The valuation of mining companies often starts with a
calculation of Net Asset Value (NAV). NAV assessment is a cumulative discounted
cash flow analysis of a company’s portfolio of assets (mines) minus associated
corporate and other overheads. Enterprise value (value of equity + debt – cash)
can be compared to NAV. If enterprise value is higher than NAV then the company
trades at a premium. If enterprise value is less than the NAV, than the company
trades at a discount.
Generally, NAV is calculated using a 5% discount rate but
there are often occurrences where this value will be increased (geopolitical risk,
asset risk, permitting). The fact that NAV is generally calculated at 5% is
very impactful. If Franco Nevada trades at a premium to the 5%NAV than that
means that the market is pricing in a lower discount rate. A 2% discounted cash
flow analysis is probably a value that brings Franco closer to its market price.
Conversely, if Alio Gold is trading at a large discount to their 5%NAV then the
market is implying that something closer to a 10% discount rate could be
Sometimes the market can be become irrational and punish projects/companies. A discount/premium to NAV analysis can be a useful way to identify “value” plays in the space.
The banks have teams of analysts that produce DCF models for
each of the mining companies. I do not have this luxury. I do have, however,
published technical reports, and market prices. Almost all technical reports
include a summary of NPV and most of the time it utilizes a 5% discount rate.
This is great. For single asset companies, I now have a view of the company’s
NAV (ignoring adjustments).
Single asset companies are the most interesting as they provide the most direct view of the company’s NAV; less noise. The chart below plots project NPV as disclosed in technical reports versus company enterprise value. These are recently published technical reports that contain over 1M oz of gold. You’ll notice that the highest value is 50%. Minera IRL Limited’s Ollachea property commands the smallest discount while a group of companies are currently trading at only 10-20% of their project’s NPV.
It’s an interesting mental exercise, hypothesizing why some
companies are undervalued relative to their projects. A few ideas:
Time/Stage: technical reports usually display
the NPV as of the time that a construction decision is made, not the current
time period. If we assume that the standard PEA is 6 years from a construction decision
and use an 8% discount rate, the discount value is 58% when compared to the
published NPV. It shouldn’t be a surprise that Valentine Lake and Mt. Todd are
at such a large discount as they are at the PEA stage. Conversely, the highest
ranked project (Ollachea) is currently in construction.
Jurisdiction: This goes without saying and
explains why a project like Block 14, located in the Sudan, is not generating
much share value for Orca Gold.
So how do we use this information? A value investor could
look at this and see if the market is mispricing any assets. We could also look
at the development path of an asset and predict a share price appreciation.
A useful example would be Valentine Lake. Marathon released a PEA on the property at the end of October which showed an after tax NPV5% close to $500M. The company currently trades at an enterprise value of $80M. A pretty strong discount but probably warranted given the project’s state. Their recent investor presentation shows that a PFS will be published in 2019 and a FS in 2020. They are having exploration success, the project looks to be improving. Obviously, there’s a due diligence component to this investment but there is a hypothesis for a re-rating over the next two years. If their discount jumps from a measly 15% to a more justified 30% in the next two years that’d provide a pretty strong return.
Seems like Valentine Lake could be an interesting opportunity.
Orezone gold corporation is a Canadian listed explorer with an enterprise value of US$51.8M. YTD they are down about 16%. They’re primary property is Bombore, located in Burkina Faso. They own 90% of the project with the government carrying a 10% free interest. Let’s see what we have here.
In July Orezone released a Feasibility study.
Ok. Lots of gold. Grade is very poor.
What does the reserve look like?
Hopefully this has a null strip ratio. Nope. 1.68:1.
Recoveries aren’t special. Get pretty low at lower grades
(80%). Large grind size (125um) and low cyanide consumption should make this a
pretty cheap process plant. 12,000 tpd.
2018 has seen its fair share of
stock price reactions to exploration results. The release of Cuale’s trenching
results sent Evrim’s stock to 200% returns within a matter of weeks. Great Bear
Resource has seen more than a 600% return since releasing the results from
Dixie Lake in September. Conversely, Skeena Resource’s Eskay Creek results have
garnered zero impact at all. This discussion will investigate some of the
market responses to Skeena’s 2018’s exploration results and try to understand the
context behind some of the reaction.
Evrim Resources, Great Bear
Resources, and GT Gold had great years, achieving 150% to 700% returns so far
in 2018. The charts below track cumulative AuEq gram * meters from intervals
>5m in length and over 100 g*m. As I would’ve expected, there’s no clear
relationship between cumulative AuEq meters and total stock returns. There is,
however, a very strong relationship between the timing of the exploration results
and the positive reaction. These folks found something that people weren’t
To contrast possible exploration
outcomes, look at the Skeena Resources vs. GT Gold. Similar cumulative AuEq
meters, very different outcomes. No reaction at all from Skeena’s results. What
Well Skeena resources is pretty small which I would’ve
thought would work in its favor (enterprise value of 22.2M). Ok, so what’s wrong
with the asset? Eskay Creek. Results looks pretty interesting. 30g/t for 28
meters at 62 meters from surface. Similar lengths and grades from a couple
holes. Project is in BC, that’s good. Barrick used to own it. Lots of ounces
produced in the past. Hmmm. Ok. So we’ve got a tired old mine that people are
discounting. I imagine these results are as the public has expected? Pretty low
enterprise value for 1.4M oz of resource in a good jurisdiction with a site that’s
probably easier to permit than most. What am I missing here? Let’s go to their
website and check it out.
Ok, interesting. Technical report issued on Nov 1st. What’s this property all about:
Location: BC, Golden Triangle
Access: All season road
History: Mining started in 1995. Barrick mined
it until 2008. On care and maintenance until 2017 when Skeena entered into an
option agreement with Barrick.
270 tpd mill
Drift and fill
Very high grade, 3.3M oz produced from 2.55M
tonnes of ore
207K oz of open pit
589K oz inf open pit
814K oz of indicated underground
261K oz of in underground
10M to Barrick
Need to spend 3.5M before 2020
Lots of penalty elements
Ok, so Eskay creek is a tired old mine. Small. Not too
surprising that the exploration results didn’t yield too much excitement.
The strip ratio is pretty low for such high grade in the
open pit. Kind of interesting. 700K ounces at ~ 5g/t. That could produce a
decent amount of cash.
Overall, it’s tough to make an investment thesis. The
exploration results didn’t do anything for the share price and they are a long
way out… I’m kind of surprised that the exploration results didn’t garner any
interest. The property would check a lot of boxes. Nothing special but good
jurisdiction and appears to have a decent shot at reopening in the future.
Skeena seems cheap.
Imagine you’ve got a gold deposit that’s 500 meters underground. It’s marginal, 5 g/t, 90% recovery, and a fairly expensive mining method. US$400M in capex is alot and your IRR is probably getting stretched. You’re building a 12% ramp so we’re looking at ~4.2km of decline length.
You’ve already pushed the limit on every other variable, so what can you do to juice up that IRR. Well, what about the underground development rate. Get to the ore 6 months earlier, increase the IRR by 5%. This could be the difference between a stalled project or one that receives financing.
I can see the motivation to push the limit with this variable. And you can certainly justify a rate that the average investor won’t be able to question because they won’t know any better. Heck, unless you’ve been on the ground at an UG mine most, people in the industry won’t understand what a reasonable underground development rate looks like.
I found a paper called “Selecting an Appropriate Decline Development Advance Rate” by S.M. Rupprecht that summarizes some information on development rates in South Africa.
Repprecht started off talking about the impacts of accelerating cash flow and the NPV benefits. Ok, nothing unexpected there.
The most useful/interesting component of the article was the development rate/month for South African operations. It’s unclear if these are FS parameters or actuals. In any case, I think this is a pretty useful chart that presents the ranging assumptions that companies could feasibly use.
Standard Dev – 70/80 meters per month, anything more should make you ask questions.
“There is something (here, perception, ideas, theories) and a function of something (here, a price or reality, or something real). The conflation problem is to mistake one for the other, forgetting that there is a “function” and that such function has different properties.” – Nassim Taben, Antifragile
People often look at something and determine the value. They can be right or wrong and not know why. The physical characteristic of the subject can bear no resemblance to its function. I think this is a pretty powerful statement.
The function of something can be completely different than the subject and inform the observer of what is relevant. In our context, the something is drill results. The function of something is the price action. Great results can lead to great price action or none at all. What does the price action tell us? Maybe the something isn’t that important. Maybe it’s a function of the jurisdiction, operator, the team (f(grade, team, jurisdiction)). If we look at comparatively positive results maybe we can learn something about the other variables in the equation.
I’ve continued the analysis of 2018 exploration results, looking at average price returns after the release of significant drilling results. In the chart below you’ll see the price return in daily increments after the release of exploration results.
I’ve sorted the data by the return two weeks after the information release. The range of results is quite large. Moosehead, Dixie Lake, Fenelon, Tatogga, and White Gold saw share price increases continue for quite a while after exploration results. Other properties not so much. So what distinguishes these properties from the rest? If there’s a steady stream of exploration results than this could propel the stock higher. Maybe it’s the the quality of release?
The chart above shows that there is a weak relationship between price returns and au grade*interval length. There are properties, however, that have great results with poor share performance… What separates Moosehead from Madsen? Tatogga from Copperstone?
What was the function that resulted in Sokoman Iron Corp’s share price appreciation??? Could we have predicted it?
I did some more digging into the drilling data. I wanted to create a more definitive list of prospects before I start to looking into more details.
First off, what do these charts show? They show drill results from properties located in North America. The drilling occurred in 2018 and the minimum interval width is 5 meters. Why 5 meters? While I’m sure that this will eliminate a lot of interesting data from some properties, I want to focus on robust results that are consistent over mineable intervals. Narrow vein mining is fine. Too complex for me though… Also, these are exploration/development properties. No producers.
The chart above shows all of the North American exploration results, grouped by property and coloured by gold grade * interval meters. If we whittle these down to grade meter levels > than 400 g/m than the image shrinks to:
Ok, this was helpful. Now we have some properties to look at. So what ones stand out?
Railroad Pinion – Gold Standard Ventures Corp
Windfall Lake – Osisko
Madsen – Pure Gold
Cariboo – Barkerville
Kiena – West Dome
Cheechoo – Quebec Precious Metals Corp
Dixie Lake – Nemont and ???
Tatogga – GT Gold
Goldlund – First Mining
Some of these are familiar names, some not so much. This seems like a good list to start digging into. In my next post I’ll start investigating Railroad Pinion.