
1 Introduction
Access and use of resources represent a key issue which has been exacerbated along the
rising and the growing complexity of modern societies. A popular way of looking at this
issue may take roots in the writings of the economist Thomas Malthus (1766-1834) [1]
and of the mathematician philosopher Nicolas de Condorcet (1743-1794) [2], both
conceptualizing that resources needs could not be covered in the future. In their works,
population is considered as the main factor causing the food resources decline and
agricultural outputs were linearly increasing. Establishing that population tended to
rise faster than yields, Malthus predicted massive food shortage for the following
century, while Condorcet submitted the concept of ”progress” which should make
production means improving at the same time as population growth. Their conclusions
differ broadly, due to their specific conception of societies and of technological impacts.
In other words, their models are not only scientific objects but also support a societal
vision. During the 20th century technical progress has brought about rising of
production and then has turned the limitation of producing rate problematic to concern
about limitation of resources themselves. Moreover, technical progress also has made
fossil energy production a centerpiece of society, supplanting then conditioning food
supply. With the increasing share of fossil fuel, draining from a finite stock of resources,
the issue raised by Malthus and Condorcet naturally turned towards the energy sector.
This concern is first epitomized in 1865 by the Coal question of W. Jevons, which
foresees many of our contemporary challenges [3]. But the most celebrated approach is
undoubtedly the 1956 work of Marion King Hubbert [4]. While crude oil extractions in
the US were booming, with an output doubling every 9 years, Hubbert addressed the
question of the continuation of the observed trends. Considering a model building on
Verhulst equation also called
logistic curve
[5] [6], Hubbert envisioned a peak of the US
conventional oil production 10 years in the future, followed by a rapid decrease. The
simplicity of the model, the audaciousness of the conclusions and the remarkable
accuracy of this trajectory up to the mid-2000’ ensured the reputation of this work [7].
Since this seminal study, a large amount of work has been dedicated to investigate
the ramification of a depletion dynamics with various types of models. Based on system
dynamics, the The limit to Growth [8] defended a holistic approach on a global scale
and promoted to widen the scope of exhaustion models, including to mineral resources.
The model was based on curves similar to the Verhulst one, the Gompertz function, and
has popularized depletion curves. In the continuity, the cumulative property of depletion
curves implying that the sum of several production peaks gives a general peak shape is
still being used to refine peak resources predictions on regional and global scale [9] [10].
Moreover, since 2000s and in the context of the energy transition mineral resources
and/or demand have been increasingly studied with forecasting models using logistic
curves or at least sigmoid curves [11] [12] [13]. Thus, even if a maximum of interest for
oil peak happened during 2010s [14], depletion curves are still prevalent and used to
support decisions, notably in energy transition management.
As a consequence, and with recycling processes being minor so far in terms of mass
flow, the mining sector evolution provides a good description of the current
management of non-energy resources and its supposed depletion.
1.1 Objectives
Due to its history and the availability of data on global scale, the topic of mining
production is a good study case for interrogating the use of future oriented model and
investigate the possible interpretation of the results.
In that respect, and given the popularity of the concept of peak production, the
Hubbert model has been chosen to illustrate two possible interpretative approaches: the
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