Resources of gold and silver - so long they will last

Gold and Silver Resources

Precious metal resources are divided intoidentified andundiscovered resources. Identified resources consist of Measured Resources that have been clearly proven, Indicated Resources indicated by test drilling, and Inferred Resources derived from these, which are further subdivided intoEconomic Reserves,Marginally Economic Reserves andSubeconomic Resources. This and otheroccurrences will be discussed in more detail in the excursus at the end of this chapter. However, the ultimately decisive parameter for measuring the subsurface precious metal resource base is the reserve base consisting of measured and indicated economically and marginally mineable resources as well as a portion of subeconomically mineable resources (marked in dark gray in Table 3.1).

Table: Resource Classification

According to the U.S. Geological Survey, the reserve base in 2009 was 0.1 million tons of silver, a ratio of just under 1 to 6.

Of the underground resources, only just under half could be classified as economically viable reserves in 2009 on the basis of the current status of extraction technologies, expected precious metal prices, existing regulatory approvals and the financing of planned mining projects on the basis of feasibility studies - 47 thousand tons for gold and 270 thousand tons for silver - which will be expanded by new discoveries and reduced by mine production.

Since the U.S. Geological Survey, which is responsible for this, no longer publishes estimated values for the reserve base since 2010, but only those for the reserves, with reference to methodological difficulties in the recording, the figures for the resource base, which were last reported in 2009, are used for the further explanations and analyses. in 2010 - after a remarkable revision of the 2009 figures - the reserves for gold were estimated as in 2009 with 47 and in 2012 with 51 thousand tons, for silver in 2010 with 400 - in 2009 it was 270 - and in 2012 with 530 thousand tons.[2] According to this, the reserves would have increased in three years for gold by just under 10%, for silver by over 90%. Apparently, in the case of silver, the part of the resources that had not previously been classified as reserves is now largely attributed to them.

The questionable-looking number capers do not allow any conclusions to be drawn about the change in the resource base, which is why no major attention should be paid to them. What is decisive is the amount of resources reflected by the reserve base, not the reserves. With regard to the further development of the resource base, there is a significant difference between gold and silver:[3] While enriched gold deposits increase with depth, silver deposits are predominantly found in upper layers of the earth's crust. Because silver deposits are closer to the surface, they are easier to find than gold deposits that are farther from the surface. Enriched silver deposits are therefore probably already widely known, whereas this is not the case to the same extent for corresponding gold deposits, which are found comparatively in deeper soil layers.

In addition to resources, the level of above-ground stocks is also of considerable importance for the development of precious metal prices. Due to high industrial demand, a much higher proportion of silver production is irretrievably lost compared to gold, so that above-ground stocks, as a potential source to meet future demand, increase more for gold than for silver. (Compare industrial demand for precious metals and supply and demand) 

Limited range of finite reserves

Statistical range is commonly used as a measure of how many years remaining underground reserves will be sufficient to sustain today's mining production of precious metals at unchanged levels. Since this easy-to-calculate parameter is sometimes used in a rather unreflective manner, we will take a critical look at it.

First, here is the formula for determining the range:

The range calculated in this way reveals how scarce the precious metals are in terms of reserves. However, it can at best be regarded as a rough guide, because it is a very static view that implies the unrealistic assumption that there will be neither technical progress nor a change in the economic and legal framework. In fact, however, both the numerator and denominator of the formula for statistical coverage contain dynamic quantities that are subject to change over time.[4]

The range of the reserve base, i.e., the currently already known resource base that already implies technological progress and changed economic conditions, is obtained by dividing the resources last reported by the U.S. Geological Survey in 2009 by global mine production in 2011. For gold, this results in a resource range of just under 36 years and for silver, one of 24 years.

Significant changes in technological and economic conditions can, however, also have a significant impact on the size of the reserve base as well as on supply and demand conditions on the precious metals markets. On the one hand, rising precious metal prices make mines profitable that previously did not permit economically viable mining of precious metals due to excessively high development and extraction costs. Furthermore, methods for recovering industrially used precious metals(recycling) could become more profitable. In addition, substitution effects may occur as a result of which precious metals, which have risen in price, are replaced by other raw materials. Finally, as a result of the increased prices, scrap gold and scrap silver stocks would presumably come increasingly onto the market. Furthermore, new discoveries of precious metals and various additional potential resource areas could change the future reserve base.

(4) Finally, there are Other Occurrences. This refers to precious metal extraction that would only become profitable under massively changed economic and technological conditions. This applies, for example, to the extraction of so-called low-grade materials, i.e. precious metal deposits that occur in the earth's crust in such low concentrations that their extraction would be unthinkable under today's conditions. Precious metals could also be extracted from hydrothermal vents at the bottom of the sea or from several thousand meters below the perpetual ice of the Antarctic or Greenland, both of which would be extremely costly. Filtration from seawater, on the other hand, would probably be out of the question for economic reasons in view of the extremely low concentrations, as would artificial production of precious metals or even extraction on neighboring planets.