WHAT IS SUSTAINABILITY IN THE CONTEXT OF MINERAL DEPOSITS?

Robert Bowell1

Sustainable development is a term that all too often has been hijacked within our society by politicians and business promoters eager to endorse their “green” credentials. Yet human society requires sustain­able growth in order to continue. However, in the context of much of society’s mineral resources what does sustainability actually mean?

In the interest of complete disclosure, I have been a miner from the age of 16 and still own my own mining operations, so I am unapologetically pro­mining. However, I also appreciate the planet we live on. The con­text and concept of mineral development being sustainable is one that intrigues me. By its very nature, mineral deposits are rarely “sustain­able”. The activity of mining consumes a resource as the development progresses. At some point, a given mineral deposit will be physically or, more commonly, economically exhausted. Other than marine evapo­rates, guano phosphate and some soda ash deposits, mineral deposits are not renewed on a human timescale of true sustainability (Fig. 1).

This is nothing new. Georgius Agricola in his mid­16th century book De Re Metallica [On the Nature of Metals (Minerals)] commented on the waste of resources in many of the mines around Freiberg, St Andreasberg and the Harz Mountains (Germany) and how they would cause problems for future generations. Yet, despite the consumption of resources, many mines continue for many generations. For example, the base metal–sul­fide deposits of the Iberian Peninsula have been continuously mined for 5,000 years; the mines of Laviron in Greece were mined over a period of 3,000 years; and Bingham Canyon in Utah (USA), although just over a hundred years old, has seen the extraction of over 19 million tonnes of copper ore and continues to produce approximately 300,000 tons of copper, 500,000 ounces of gold, 4 million ounces of silver, 30 million pounds of molybdenum and 1 million tons of sulfuric acid every year! So, although not sustainable, certainly long lived (Fig. 2).

There is a growing interest in defining sustainability in the minerals industry. The papers in this volume highlight some of the research interest. Another recent and excellent publication on the topic focuses on the sustainability and historical development of global coal and copper resources, defined by the authors as “critical components in our species development” (Golding and Golding 2017).

1 SRK Consulting (UK) Limited 5th Floor, Churchill House, 17 Churchill Way Cardiff, CF10 2HH, Wales, UK E-mail: rbowell@srk.co.uk

Despite often long and active periods of mining, most mines do not close as a result of the exhaustion of all ore. Mines close because the ore that is left costs more to extract at prevailing metal prices than will be realized in revenue. As many ore bodies reach this maturity or are abandoned, potential negative environmental impacts can and do occur.

It is conceivable that the mining legacies of previous generations can, through new technology, be considered as providing an alternative ore source, possibly in perpetuity: truly “sustainable mining”. A recent publication by Nordstrom et al. (2017) addressed the potential methods that could be applied to offset environmental impact mitigation and produce critically required metals from contaminated water discharged from mine sites. But is there really value in such an exercise?

An evaluation on mine waters discharged from Iron Mountain (California, USA) (Fig. 3) indicates “ore grade” concentrations up to 650 mg/L copper and 2,600 mg/L zinc in water with a pH less than 1.5 at a flow rate up to 50 L/s (Alpers et al. 2003). The calculated value of the water in terms of metals (primarily as copper and zinc) could be in excess of US$12,000 a day, making it a mid­size base­metal producer. This water also has a wide range of other potentially valuable trace

Dr Robert Bowell, is a Corporate Consultant (Geochemistry) at SRK Consulting with 27 years’ experience. His background is in applied geology in tropical and deeply weathered terrains and mining consulting in the fields of due diligence, financial and technical audits, process chemistry, envi­ronmental geochemistry, environmental engineering and mineralogy. He specializes in the application of chemistry and min­eralogy to solve engineering problems.

1811-5209/17/0297-$0.00 DOI: 10.2138/gselements.13.5.297

Figure 1 Hajipir Marine Chemical Operation (Northern India). This operation produces potash, halite and bromine by sea water evaporation and

chemical separation: production is over 130,000 t per year of product.

Figure 2 Bingham Canyon (Utah, USA). Open pit copper operation that covers some 9 km2 and has mined about two billion tons of material in over

100 years of operation.

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components as well (such as Ag, Pb, Cd, Li, Be, Ga, Ge, Sn, Te, Tl, and rare­earth elements). However, the reality is that the total metal value can be very different from the economic value because it does not account for the cost of metal extraction, refining or transport. These costs can be on the order of 60% or more of total metal value. So, despite the attractive costs, if it costs $8,000 to $10,000 per day to recover these metals then the operation is less attractive as a commercial concern but could be driven by other factors, such as environmental clean­up.

Metal recovery from mine waters, such as at Iron Mountain, represents a potential source of revenue to offset water treatment costs and, in some places, may even represent an economic project in its own right.

A caveat exists, however: even if the “ore potential” can be proven and the technology can recover economic amounts of metal, there may still be little incentive to “re­mine” many old mining districts.

Companies that attempt such re­mining ventures may be held responsible for all past mining legacy, as well as any new disturbance. Furthermore, the mere mention of metal value from these old districts could result in legal action from property owners or bankruptcy trustees who will lay claim to any recovered value. It is quite conceivable that potentially “sustainable” developments could become unattainable simply due to legal quagmires. So, despite the potential for extract­able minerals, in some cases they could become “legally off­limits”.

Nevertheless, in the current environment of high­metal demand and exhaustion of historically important metal sources, different sources of metals or technologies to extract metals will have to be found. This could be from mining deeper primary mineral resources, using new types of ore (such as bauxites) providing rare­earth elements or returning to recover extractable minerals from abandoned mines. These challenges will require a good understanding of the mineralogy and geochemistry of the target metals and minerals in order to identify such “sustainable” opportunities. The geological community must be suitably trained and equipped to characterize such “sustainable” opportunities.

REFERENCESAlpers CN, Nordstrom DK, Spitzley J (2003) Extreme acid mine drainage from

a pyritic massive sulfide deposit: the Iron Mountain end­member. In: Jambor JL, Blowes DW, Ritchie AIM (eds), Environmental Aspects of Mine Wastes. Mineralogical Association of Canada, Short Course 31, pp 407­430

Golding B, Golding SD (2017) Metals, Energy and Sustainability: The Story of Doctor Copper and King Coal. Springer International Publishing, 196 pp

Nordstrom DK, Bowell RJ, Campbell KM, Alpers CN (2017) Challenges in recovering resources from acid mine drainage. In: Wolkersdorfer C, Sartz L, Sillanpää M, Häkkinen A. (eds) Mine Water and Circular Economy. Proceedings of the 2017 International Mine Water Association Conference held 25­30 June 2017 in Lappeenranta, Finland. International Mine Water Association, pp 1138­1147

Figure 3 Mine-water discharge from Iron Mountain (California, USA). The pH of the water ~1.5; copper content in this water is ~0.5–0.6 g/L; zinc

content is ~2 g/L.

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Introduction

The Kyrgyz Republic has a long history

of mineral exploration, commencing in

the 1930s and continuing during the

former Soviet times, up until 1991. A

number of large mercury, antimony, and

fluorite deposits occur in the southwest

part of the country, some of which were

substantial underground and open-pit

mines. The terrane is undulating and

is not exposed to a severe winter cli-

mate. All of the mining districts are eas-

ily accessible via a paved highway from

the provincial capital of Osh, which is

the second largest city in the Kyrgyz

Republic (Fig. 1). Gold exploration in

the region during the past two decades

has identified numerous deposits, now

recognized as Carlin type (Yakubchuk et

al., 2002; Seltmann et al., 2004; Rickle-

man et al., 2011). Limited work by Bar-

rick and Phelps Dodge in the late 1990s

confirmed the presence of Carlin-type

mineralization, and subsequent drilling

by ASX-listed Manas Resources between

2005 and 2010 discovered the Shambe-

sai and Obdilla gold deposits (www.

manasresources.com). Field visits and

sampling, conducted by the authors

in October 2016, of the main mer-

cury and antimony mining districts at

Khaidarkhan, Kadamzhai, Chauvai, and

Chonkoy (Fig. 1) further highlighted the

exploration potential of the southwest

part of the Kyrgyz Republic for signifi-

cant Carlin-type gold deposits.

Regional Setting

The Kyrgyz Republic may be conve-

niently divided into three E-W–trend-

ing tectonic units: the Northern,

Middle, and Southern Tien Shan. The

southwest part of the country com-

prises the western portion of the South-

ern Tien Shan and is mainly composed

of middle to late Paleozoic fore-arc

accretionary complex, which was sub-

jected to intense folding

Advancing Science and Discovery

JULY 2017

NUMBER 110

NEWSLETTERwww.segweb.org

to page 14 . . .†Corresponding author:

e-mail, djkdoug@gmail.com

The Carlin-Type Hg, Sb, As, Au, F, Tl Deposits

of the Southwest Kyrgyz Republic

Douglas Kirwin (SEG 1997 F),† Alexander Becker (SEG 2017), Iaroslav Bandurak, and

Brian Lueck (SEG 2014), Geological Consultants

SEG

2017 Conference

See p. 25–36 for details

CUGB

Ore Deposits of Asia: China and Beyond

September 17–20, 2017 Beijing, ChinaO

seg2017.org

FIGURE 1. Location of the Hg, Sb, As, Au, F, and Tl districts, southwest Kyrgyz Republic.

INTRODUCTIONNovember 2016 marked the 25th anniversary of the announcement of the discovery of diamonds in the Lac de Gras region of the Northwest Territories (NWT) of Canada. This is an anniversary that deserves great celebra-tion. From 1998 through 2015, it is estimated that Canada produced 172,700,000 carats of diamonds with a value of approximately CDN $29 billion (Natural Resources Canada, 2016). The discovery of diamonds in the NWT and the subsequent exploration, mining, and business success is an inspiring story to those of us in the exploration and mining business. The combination of vision, commitment, hard work, application of sound scientific principles, timely investment, and supportive government and communities can have a positive transfor-mational effect on a region and a country. This paper summarizes the formation and develop-ment of the diamond business in Canada.

Most of the world’s natural diamonds have been produced from mines exploiting kimber-lite volcanic complexes, with the remainder coming from lamproite volcanic complexes and alluvial and marine gravel deposits and conglomerates.

Advancing Science and Discovery

JANUARY 2017 NUMBER 108

NEWSLETTERwww.segweb.org

to page 12 . . .†E-mail, brooke.clements@telus.net

The Canadian Diamond Business: 25 Years and Going StrongBrooke Clements (SEG 1990),† JBC Ventures Ltd., North Vancouver, BC, Canada

SEG

2017 Conference

See p. 27–38 for details

CUGB

Ore Deposits of Asia: China and BeyondSeptember 17–20, 2017 Beijing, China

O

seg2017.org

FIGURE 1. Major North American kimberlite and lamproite districts. Refer to page 12 for the names of numbered districts.

LegendDiamond MinesPost-1990 DiscoveriesKimberlite DistrictsLamproite DistrictsInterpreted Archean Basement > 2.5 billion yearsInterpreted Proterozoic Basement > 1.5 billion years

Interested in Ore Deposits?

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