Monday , 17 June 2024

What to Look for When Considering Which Gold Mining Companies to Buy (+6K Views)

While investing in gold mining companies is not quite as simple as novices to this sector might at firstgold-mining conclude, neither is it so overwhelmingly complicated as to make these companies inaccessible to individual, retail investors.

Below are a number of things to look for when considering an investment in gold mining companies:

1. A Minimum of 1 Gram of Gold per Ton of Ore
For gold miners, the starting point would be to look at ore with 1 gram of gold per ton of ore. That’s right, ore with as little as 1 gram/ton is potentially rich enough to support commercial mining. Of course, with this low level of concentration of gold, it will generally require both vast tonnages and favorable geology for ore of such a low grade to support commercial mining operations. Generally speaking, what exploration companies are looking for is ore with several grams of gold per ton.

What companies looking for gold (and mining gold) need to see is enough tons of such ore to justify all the preliminary drilling, the resource estimate, the feasibility study, and ultimately the construction (and operation) of a mine.

2. Large Ore-bodies Compressed within a Narrow Range of Depth
Even when looking at the quantity of gold in an ore-body, tonnages alone do not tell the whole story. Companies drilling for gold sometimes go down a mile or even further beneath the ground. What companies (and investors) want to see is for the quantities of gold in these ore-bodies to be compressed within a relatively narrow range of depth.

For example, let’s suppose that two companies have identical grades and tonnages of gold in their properties. The “veins” of gold for Company A start at 50 feet below the surface, but continue all the way down to 5,000 feet below the surface. With Company B, on the other hand, the gold doesn’t start until 200 feet beneath the surface, but the mineralization only goes down 1,000 feet.

It would obviously require much more excavation for Company A merely to get access to all its ore, and likely much more ore extracted to mine all the gold. All of this additional blasting and digging dramatically erodes the potential profitability of the mine, so how the gold is distributed within an ore-body is a factor which investors must note in their research.

Much of this information is revealed to us in the drilling samples which mining companies extract and analyze. A drilling core sample is a vertical cross-section of the ore which ideally is perpendicular to the vein in question – so that the sample represents a “true width” of the particular vein. Since veins of ore can exist at various angles relative to the surface, and can also bend and twist through the Earth’s crust, it can be very challenging for the miners doing this drilling to produce such ideal core samples.

Assuming this is the case, when you examine the drilling results of a mining company, the data is generally presented as a series of “intervals” in each core sample, with each “intercept” representing a separate vein of gold. Thus, the drill samples will tell miners (and investors) the grade of the ore, the thickness of veins, and the number of veins – over the total depth of the drilling sample. This means that an ideal core sample would demonstrate high grades (i.e. averaging several grams per ton), thick veins, and (hopefully) many such veins. Since these intervals can be very thick, in some cases exceeding 100 feet, the grades within veins can vary considerably. Where the concentrations are unequal, the person evaluating the core sample will generally also list sub-intervals within the intercept – and indicate the especially rich segments of such intervals.

There is an incredible amount of variation in veins of ore. In the extreme, very rich ore can contain hundreds or even thousands of grams per ton. While veins of ore can (and do) exceed a hundred feet in thickness, such veins can also be extremely narrow – sometimes only a few feet thick. Indeed, it is not uncommon in the case of “high grade” ore for the geological formation to be a series of very rich grades, but very narrow veins.

3. Easy Access
Naturally, this incredible geological diversity means that there are numerous methods for mining ore. Our primitive ancestors (and modern “prospectors”) got most of their gold through “panning” or “dredging” gold that has reached the surface – and been washed into the beds of rivers and streams. For gold that is near, but still beneath the surface, the preferred method of mining is generally an “open pit” operation. As the name describes, this is where instead of constructing a true “mine” under the ground, a mining company will simply start at the surface and strip-off one layer of rock after another.

a) Open Pit Mining
The advantage of open-pit mining is that it avoids the costs and engineering challenges of constructing an underground mine. Secondly, pit-mining operations are generally very large-scale operations – requiring vast tonnages of ore to justify all the equipment and manpower necessary to run such an operation. However, as companies go deeper and deeper with their pit-mining, extracting gold becomes relatively more expensive. As a result, in the case of ore-bodies which start at the surface, but continue to considerable depths, it is not uncommon for a mining company to initially extract ore in an open-pit operation – and then after the near-surface ore is extracted, construct a conventional mine to extract the remaining ore in the most economical manner.

b) Underground Mining
Generally speaking, a company will need to find higher grades of ore to economically justify an underground mine than an open-pit mine – although as I mentioned earlier, open-pit mines are generally only economically feasible where there are vast tonnages of gold for extraction.

While veins of gold are relatively narrow, the length of these veins can run for miles beneath the Earth’s surface. Some of the world’s largest/oldest mines end up as vast labyrinths of tunnels occupying areas of many square miles. As a result, even more important than the data which is obtained vertically through each individual drill-sample are the number of such drill-holes produced in a drilling program.

It is the accumulation of dozens (and often hundreds) of drilling samples which map-out the dimensions of any given ore-body. Obviously, if such holes are placed closer together, the data obtained is more precise. However, with drilling being a very expensive process, there is a large economic incentive for companies to space-out the holes quite widely (at first) to gauge the overall dimensions of an ore-body. Then subsequently once those dimensions are identified, companies will “fill in the gaps” with more drilling within this perimeter – in order to provide geologists with enough data for a “resource estimate”.

With drilling ore-bodies being such a capital-intensive process, drilling always begins tentatively. Modern “imaging” technology and other forms of geographical analysis (including near-surface “trenching”) will provide companies with some initial “targets” for there first drilling efforts. Also, since every extra foot which these drills bore into adds to the costs, an initial drilling program will generally involve only a dozen drill-holes or so (sometimes even less) and unless the geologist has reason to suspect that mineralization is very deep, those first drill-holes will also be quite shallow.

What to Look for in Drilling Results
For potential investors viewing the results of such drilling, there are two indicators which they typically look for:

  1. to see most, if not all, of the drill-holes showing significant levels of mineralization (i.e. several grams of gold per ton in each intercept).
  2. to see evidence of even greater mineralization. Specifically, they will look to see if the drilling reports that mineralization is “open” (i.e. it continues beyond the scope of the original drilling). Mineralization could be “open” in any direction laterally, and also potentially “open at depth” – meaning that mineralization still continues lower at the deepest depth reached by the drill hole. The miners themselves are naturally even more interested in such data – since this information will guide them in deciding where to drill their next holes, how many such holes they should drill, and how deep they should go with subsequent holes. The nature of the “game” is to try to learn (and demonstrate) as much about an ore-body as possible – with the least possible expenditure of capital.

Since exploration companies generally have no sources of revenue, being efficient (and a little lucky) with their drilling can and does determine which of these companies will survive and thrive, and which will struggle to stay afloat or simply fold.

What to Look for in a Feasibility Study
Once a drilling program has identified a body of ore with the potential to support a commercial mining operation, this is only the starting point of analysis. A “feasibility” study must be done to evaluate a number of other factors (a more preliminary form of this analysis is called a “scoping study”).

1. % of Gold Oxides vs Gold Sulphides
Ore containing gold falls into two categories of chemical/geological composition: sulphide-based ores and oxide-based ores. Gold “oxides” are preferable for mining since the chemical “bond” which locks the gold to other chemical elements is not as strong. As a result, processing such ore is cheaper, easier, and generally yields a higher “recovery” rate than with gold sulphides.

2. % of Gold that can be Extracted
The “recovery rate” is self-explanatory. It is the percentage of gold contained in a given quantity of ore which is successfully extracted, and ready for further processing (and ultimately refining into bullion). In simple gold oxides, a recovery-rate above 90% is not unusual. However, because gold oxides contain gold that is cheaper and easier to extract, most of the world’s easily accessible gold oxide deposits have already been mined – meaning that modern miners are forced to obtain much more of their gold in sulphide-based bodies of ore.

With gold sulphides, the much tighter chemical bond between the gold and other elements is much more technically challenging. Attempting to extract the gold using the same methods of extraction as with gold oxides would result in vastly inferior recovery-rates – closer to 50% recovery. Primitive methods of secondary processing of such ore were developed, which improved recovery rates, but resulted in vast quantities of highly-toxic waste.

Unless such “tailings” were collected and contained very carefully, the result was generally environmental devastation. Such primitive gold-sulphide mining operations have been among the worst “offenders” when it comes to mining-based pollution. Fortunately, modern technology has devised new methods for extracting gold from sulphide deposits – which are not only much more environmentally “friendly” but also yield higher recovery-rates.

Thus, while it is generally preferable for a mining company to mine gold oxides, sulphide deposits are no longer as problematic with respect to both costs and permits as they were in the past. Which leads to another important issue for gold miners, and mining, in general – permits.

3. Ease of Permitting
It doesn’t matter how many millions of ounces of gold a mining company discovers if it is never allowed to mine it. Thus, potential investors must look at the location of any gold deposit both in terms of local and national considerations. Locally, deposits which are close to large populations or environmentally sensitive sites will generally have more difficulty (and need to provide better operational guarantees) to obtain approval for a commercial mining operation.

However, just as looking for gold in districts which have a history of successful mining tends to provide better chances of success, similarly it is more likely for miners to obtain the necessary permits and approval for a new mine in areas which have previously approved other mines in the vicinity.

Potential investors should not simply assume that mining companies are necessarily big polluters, and the enemies of local inhabitants. Modern, responsible mining operations can co-exist with human habitation, and even be compatible with all but the most-sensitive natural habitats.

Despite this fact, the receptiveness of national governments toward mining operations varies dramatically from nation to nation. Some governments have a strong aversion to any mining, either through previous, negative experiences with other primitive or reckless miners, or simply due to an out-dated fear of such problems. New companies seeking to obtain permission for a future mine can face sometimes insurmountable problems here, so potential investors must take note of the jurisdiction where a particular deposit is located.

Similarly, some local populations have similar aversions to mining or there may be some competing claim to the right of a miner to build and operate a mine. As such, there is no substitute for investors “doing their homework” in such situations –to assign a realistic probability for the company in question to obtain final mining approval.

4. Presence of other Polymetallic Ores
Up to now, I have been discussing hypothetical bodies of ore with the unstated assumption that they only contain one commercially valuable mineral. In fact, most bodies or ore which contain gold or silver will generally contain one or more other mineral elements with commercial value.

These “byproducts” will add additional complications to the processing of ore, although modern metallurgy has progressed to the point where these problems are nothing more than minor considerations. Typically what occurs is that the metallurgist will seek to maximize the recovery-rate of the primary metal (gold or silver) with secondary processing yielding lower recovery-levels for the other metals contained.

Naturally, these byproducts will offset the production costs of the primary metal, through the “credits” obtained by selling these other metals. This lowers the production costs for each ounce of gold/silver (the “cash costs”), however it also dilutes the “purity” of the miner.

For example, a gold miner which obtains 25% of its revenues from copper also contained in the ore, or a silver miner which also produces large amounts of lead and zinc (both very common scenarios) are no longer the “pure plays” which are favored by investors. Such companies generally receive inferior valuations relative to revenues/profitability, and also are affected by price-changes for these other metals.

5. Availability of Financing
Even where geological conditions are favorable, and national and local governments are amenable, satisfying these many criteria still does not guarantee that a mining company will be able to capitalize on these factors, and construct and operate a profitable mine.

…financing is…a strategic factor for investors. Pure exploration companies will have to raise new capital each time their last source of funding begins to dwindle. Companies at a more advanced stage will typically seek a new infusion of capital each time they seek to make another major step in going from finding a deposit to mining it. Thus investors must keep track of both the current cash position of these companies, and what stage they are in with respect to development of their property.


Those investors who:

  • do their homework,
  • diversify into a “basket” of these companies,
  • and exercise discipline in their buying and selling

should expect to be able to leverage the gains of precious metals and obtain a higher rate of return than in bullion, alone – over the long term.

The volatility of these companies is not for the timid, however. Make sure you’re ready for the “ride” before you choose to get on one of these “roller-coasters”.

The comments above are edited ([ ]) and abridged (…) excerpts from the original article by Jeff Nielson

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