SME Annual Meeting

Feb. 23-25, Denver, Colorado

Preprint 04-170
SUSTAINABLE DEVELOPMENT AND EXPLORATION

V. T. McLemore and D. Turner

New Mexico Bureau of Geology and Mineral Resources, Socorro, NM
Arizona Dept. of Environmental Quality, Phoenix, AZ

ABSTRACT panies operate an industrial enterprise with importance to local and

national economies, generate tax revenues, and provide sustenance
The mining industry is at a crossroad. To sustain our technically
to numerous individuals and families (Parr, 2001). Under sustainable
based society, demands for commodities are increasing, and explo-
development concepts, not only are mining companies expected to
ration for these commodities is a must. The debate is between sus-
produce profits for the shareholders, but mining companies also are
tainable development and the status quo and begins with exploration,
expected to provide resources to the local community that will sustain
where it is determined if a mineralized area contains enough poten-
its growth during and after mining. In many rural areas, mining com-
tial ore to be mined economically. Mineral deposits are relatively rare
panies provide community leadership and emergency medical per-
and depend upon certain natural geologic conditions to form and may
sonnel that the rural communities would not otherwise have. The
not always occur in locations that are most suitable to society.
company is sustainable only if it continues to develop new reserves.
Exploration can be compatible with environmental protection and
This is accomplished during the exploration stage of mining.
social responsibility, but difficult challenges face the industry to devel-
op a property that is environmentally, economically, and socially DEFINITIONS
responsible.
A mineral occurrence is any locality where a useful mineral or
INTRODUCTION material is found. A mineral prospect is any occurrence that has been
developed by underground or by above ground techniques, or by sub-
What is sustainable development? Everyone seems to have a
surface drilling to determine the extent of mineralization. These two
slightly different view of sustainable development. The Brundtland
terms do not have any resource or economic implications. A mineral
report (United Nations, 1987) defines sustainable development as
deposit is any occurrence of a valuable commodity or mineral that is
“development that meets the needs of the present without compro-
of sufficient size and grade (concentration) that has potential for eco-
mising the ability of future generations to meet their own.” Exploration
nomic development under past, present, or future favorable condi-
for new materials is an integral part of sustainable development.
tions. An ore deposit is a well-defined mineral deposit that has been
Mining is essential to maintain economic wealth because it is
tested and found to be of sufficient size, grade, and accessibility to be
one of the ways that new wealth is created (fishing, farming, forestry
extracted (i.e. mined) and processed at a profit at a specific time.
are others). Without a continued supply of natural resources to man-
Thus, the size and grade of an ore deposit changes as the econom-
ufacture and produce products that society demands, society cannot
ic conditions change.
continue to improve and grow technologically. Recycling, re-use, less
Mineral deposits and especially ore deposits are not found just
use, materials replacement, and alternative product design are some
anywhere in the world. Instead they are relatively rare and depend
ways to replace mined commodities, but exploration and mining of
upon certain natural geologic conditions to form. The requirement
new resources is still required.
that an ore deposit must be extracted at a profit makes them even
Mining began with the first prehistoric man that used a stone or
more rare.
rock as a tool for hunting, tanning, or crushing to make his life easier.
Industrial minerals are any rock, mineral, or other naturally
Today just about everything we use involves mining—even agriculture
occurring material of economic value, excluding metals and energy
or the growing of crops depends upon minerals for fertilizers to
minerals. Examples of industrial minerals include perlite, pumice,
enhance growth, pesticides to ward off predators of plants, and tools
gypsum, salt, mica, aggregates (crushed stone, sand and gravel),
to plant and harvest the crops. Indeed, the use of raw materials in the
zeolite, calcite, both silica and chemical limestone flux, mineral des-
United States and the world increased dramatically in the 20th centu-
iccants, feldspar, clay, humate, fillers and extenders, wollastonite, and
ry and is continuing to increase in the 21st century (Wagner, 2002).
semi-precious gemstones (Barker and McLemore, 2004).
However mineral resources generally are not renewable. When mining
occurs, the ore body being mined is depleted. One factor of sustain- STAGES OF MINING
able development is to continue to supply society with the raw materi-
als, metals, industrial minerals, and energy minerals it requires. This One of the principles of sustainable development in mining is
requires exploring for new resources. However sustainable develop- that every mining operation has a beginning and an end (Fig. 1;
ment is not about sustaining a particular mine. Instead, mines have a MMSD, 2002). The mine-life cycle can be divided into four stages:
beginning and an end, which we refer to as the mine-life cycle (Fig. 1). exploration, development, operations, and closure/post-closure. Only
Mining companies realize that they must meet mineral needs of the exploration stage is discussed in this section; the other stages of
our society, while protecting the health, safety, and welfare of its work- mining are discussed in other sessions of this symposium and in
ers, the surrounding community, and the environment. Mining com- McLemore et al. (2004).

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 SME Annual Meeting
Feb. 23-25, Denver, Colorado

EXPLORATION STAGE OF MINING • Geochemistry of the deposit, specifically the presence

of sulfides that may lead to acid drainage
The first stage of mining is the prospecting or reconnaissance
• Ease of recoverability of the commodity by known pro-
stage, or the identification of areas that might contain mineral
cessing techniques (mineralogy, grain size of the ore
deposits (Hartman, 1992). Once a mineralized area is located, it is mineral, hardness, impurities)
determined if the mineralized area contains enough potential ore to • Available land access for safe, long-term storage of
be mined economically. If a potential mineral deposit is located, then mine wastes
the company performs a feasibility study to determine if the deposit • Geotechnical characteristics (stability of underground
can be mined under future economic conditions. If a mine cannot openings, steepness of open pits, slope stability, etc.)
afford the cost of environmental remediation, then the deposit proba- • Social setting of the deposit (what does the local com-
bly should not be developed. Claim staking, road and trail building, munity feel about a mine in their neighborhood).
and helicopter transport typically occurs during the exploration stage,
and may continue into the advanced exploration and feasibility These factors should be considered during the exploration
stages. phase.
A variety of exploration techniques may be employed in both the
exploration and development stages, including literature searches, CHALLENGES FACING THE MINING COMPANIES
geological mapping, geochemical exploration (rock, soil, and water Many of the challenges mining companies face today differ from
sampling and analysis), geobotannical surveys, geophysical surveys the challenges the industry has faced in the past.
(surface, subsurface, airborne, satellite), aerial photography, and
drilling. Most exploration programs, however, never result in opera- • It is a global market with global competition for
tional mines, making exploration a relatively high-risk investment. resources, land access, money, and markets.
The modern explorationist, typically a geologist, has more tools • Many people have little if any understanding of where
to choose from when locating ore deposits than his predecessors. products they use everyday come from or where real
Satellite images, remote sensing imagery, geologic maps, geophysi- wealth comes from.
cal studies, and geologic reports are examined to identify favorable • Local and national governments depend upon the rev-
areas for exploration. Technological development has made it possi- enues generated by mining companies to be sustained
ble to perform exploration with much less physical disturbance to the far into the future and yet these same governments are
land. This is an important contribution to the wellbeing of the environ- supposed to impose and enforce strict health, safety,
ment and a key to sustainable development. Mineral deposit models and environmental regulations.
• Local communities expect that the mining companies
(tectonics, metallogenesis, environmental models) are useful in iden-
will provide employment, infrastructure, and other ben-
tifying targets. These same techniques can be used in environmental
efits and will leave them better off than when the mine
studies. Once the mineralized areas are identified, the explorationist
started.
conducts field examinations of the area. Surface sampling, stripping,
• Communities expect mining companies to involve them
drilling and trenching, bulk sampling, and even panning are still used in the decision-making process in all aspects of mining
in the beginning phases of exploration today. and close-out plans.
Outcrops are examined for favorable lithology and mineralogy, • Society expects mining companies to adhere to much
and samples are submitted to laboratories for chemical analyses. higher standards of performance and that the industry
Most samples are solid (i.e. rocks, soils, stream sediments); other will avoid ecologically and culturally sensitive areas.
sample media can be collected and chemically analyzed (i.e. biolog- • Mining companies are expected to protect and enhance
ical, water, air). The explorationist also can use geophysical and geo- biodiversity. Many people believe that the benefits of
chemical techniques not available to the prospectors of the 1800s. mining are not enough to justify the impacts on biodi-
Detailed geologic maps are prepared to help characterize the rocks versity (Blench, 2001; http://ww.iied.org/mmsd/activi-
at the surface and to predict the rocks in the subsurface. Despite the ties/biodiversity.html, accessed on October 24, 2003).
numerous exploration techniques available, ultimately the deposit • New mining and processing methods that have a lower
typically must be drilled. Several drilling techniques are available that environmental impact than methods being currently
provide samples of the hidden potential deposit. In some cases, test used are needed.
(or exploration) pits, adits, and drifts are excavated in order to provide • An exploration company may need to transfer a grant of
enough material for metallurgical testing and other purposes. New exploration rights in order to involve other entities with
exploration techniques are essential in quickly defining areas of greater financial and technical capacities (Parr, 2001).
potential mineralized bodies as well as eliminating or reducing envi- In some situations, local regulations can prevent this
ronmental impacts in the area to be explored. Ultimately, the mini- type of transfer.
mum grade to be mined is determined by the market price of the • Better ways of converting land that are liabilities into
mined commodity. lands that are assets.
• Can companies establish specific targets based on
Some of the issues that could arise during exploration that apply
long-term environmental and community wellbeing?
to sustainable development concepts include land access, relations
with the local community, especially indigenous peoples, environ-
Some of the same traditional challenges remain for the mining
mental impacts, rare and endangered species, health and safety of
company as before.
employees and the public, etc. Additional factors that affect whether
or not the deposit can be mined include: • In order to reduce the risk of successful exploration,
areas with favorable geology and known mineral
• Location and size (is the location, size and shape of the
deposits are examined. However, these areas are limit-
deposit amenable to available low cost mining and pro-
ed.
cessing methods)
• Mineral deposits are found in specific locations not
• Mining rate (high mining rate usually means lower unit
always compatible with society’s needs and wants (not
costs)
in my backyard syndrome).

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 SME Annual Meeting
Feb. 23-25, Denver, Colorado

• Many of the largest, highest-grade mineral deposits that INDIGENOUS CULTURES

are closest to surface and closest to market have been
The mining community recognizes indigenous cultures as a
depleted or are currently in production or on standby.
major stakeholder in exploring for and developing potential mine sites
• Financing a mine can be moderate to high risk and
some commodities are perceived by investors to be in and adjacent to native lands (Downing et al., 2002; Warden-
politically incorrect (such as uranium). Investors expect Fernandez, 2002). Yet many challenges still face the mining industry
higher returns and dividends. in gaining access to these lands. In many areas, mining is not com-
• Generally accepted risks associated with a specific tar- patible with their religion and culture. For example, the Navajo Nation
get still provide a challenge in mining (climate, sulfides, in New Mexico and Arizona is experiencing a dilemma brought on by
water, access, etc.). mining and oil and gas exploration. The Nation profits from oil, gas,
• Securing a well-trained and educated workforce is a and coal production, yet many tribal members are opposed to miner-
challenge. al development of any kind and are opposed to any exploration with-
• The workforce and the public demand significantly fewer in and adjacent to their reservation. To compound problems between
work-related accidents and health effects from mining. mining companies and indigenous peoples, in some areas, coal and
• Compared to other industries, the financial improvement gas resources are being developed, even though nearby residents do
in mining has not increased significantly to attract not enjoy the benefits of coal or gas heat (Romero, 2003). In another
investors (Adams, 2002). example, Teck Cominco Co. has established favorable relationships
with the Native Americans in the area and formed a partnership to
Exploration geologists are now being asked to collect environ- develop the Red Dog deposit in Alaska (Horswill and Sandvik, 2000).
mental data as well as identify environmental concerns. Even indus-
trial minerals operations, traditionally perceived as having few, if any, EXPLORATION TECHNOLOGIES
impacts on the environment are under public and government pres- Exploration is traditionally geology driven, but today and in the
sure to identify and plan for environmental impacts (Barker and future, exploration will be technology driven as well. The search for
McLemore, 2004). Permitting typically begins during exploration in new reserves depends upon favorable geologic settings. Thus, it is
many areas of the world. Some of the additional information request- important to have current geological models that include the origins
ed by the environmental departments of the mining companies, of the ore body, the geologic history, the genesis of the deposit, and
stakeholders, and other interested parties is summarized in Table 1. mineral deposit grades and tonnages, because these criteria deter-
mine the technically and economically feasible mining method. For
example, low-grade disseminated ore bodies usually cannot be
Table 1. Information that should be identified and collected dur-
mined economically by underground methods; open pit mining is the
ing exploration (National Academy of Science, 2002).
most efficient way of developing such ore bodies. The National
Academy of Sciences (2002) has identified needed research and
Data
technology methods for exploration of mineral deposits, briefly sum-
marized below and in Table 2.
Water quality (surface and ground water)
Chemical analyses of soils, especially metals
Trace elements in ores, especially elements of Table 2. Needed research methods and technologies for explo-
environmental concern ration of ore deposits (National Academy of Sciences, 2002).
Presence of asbestos and asbestiform minerals
Potential for acid rock drainage (ores, wastes, and adjacent terrains) Method
Location of aquifers in relation to ore bodies
and areas of mine development Geologic methods
Identification of areas of sensitive environmental concern Robust thermodynamic and kinetic geochemical data and models
Climatic data, especially precipitation New ore deposit models, especially for deposits with minimal impact
Social and community needs and environmental issues on the environment
Presence of indigenous cultures and their needs and issues More sophisticated 3-dimensional geological and ore reserve
models
Better geohydrologic models relating to mineral deposits,
LAND ACCESS
including industrial minerals deposits
The most important aspect of exploration is that there is access Geologic maps of mineralized areas
to mineralized areas, not only for actual exploration, but also for con- Databases of mineral deposits and mineralized areas
tinued mine development. “The absolute worst thing that can happen Geochemical and geophysical methods
is denial of an opportunity to mine after extensive expenditures over Hand-held and down-hole analytical instruments
long periods of time with little chance of success and major invest- Improved cross-bore hole correlation methods and characterization
ments for site specific evaluations have finally identified an economi- Better understanding of element mobility in soils and water
cally exploitable mineral deposit” (Parr, 2001). Many countries, includ- Drones (unmanned aircraft) for airborne geophysical methods
ing the United States and Canada, have legislated areas that are off- (for example Magsurvey’s UAV, www.magsurvey.co.uk,
limits to exploration and mining (i.e., Wilderness Areas, National accessed on November 5, 2003)
Parks) in an attempt to protect environmental and cultural sensitive Low-cost, seismic methods
areas. Decisions concerning land access tend to be made in the polit- Better interpretation of remote sensing and hyperspectral data
ical arena without regard to the presence of important mineral (Livo and Knepper, 2004)
resources. A much better way (and more sustainable) is for a multi- More sophisticated 3-dimensional geochemical, hydrological,
stakeholder planning process to be implemented (as in Manitoba) to and geophysical models
develop a land access policy and division that pays attention to envi- Drilling technologies
ronmental, social and mineral resource values. Application of existing petroleum and geothermal
techniques to mineral exploration

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 SME Annual Meeting
Feb. 23-25, Denver, Colorado

New mining and processing technologies provide for new explo-

Table 2. Needed research methods and technologies for explo- ration targets. Development of better methods of bulk mining under-
ration of ore deposits (National Academy of Sciences, 2002). ground will enable less expensive mining with minimal impact to the
(Cont’d) surface. Optimizing slopes (steeper, stable, and safer) in open pits
result in less waste rock, less land disturbance, and less mining
Improvements in drilling methods costs. In optimization during operations, companies must be careful
Changes in corporate policy to prevent ongoing instabilities upon closure. Advanced processing
Diversification into other commodities, especially industrial minerals technologies, some based on biological processes and solvent
Developing and maintaining expertise in exploration extraction-electrowinning (SX-EW), are improving recovery rates and
reducing the costs of mitigating environmental impacts. For example,
the advent of heap leaching and SX-EW has had the effect of cutting
In the 1980s, mineral deposit models became popular that incor- out whole sections of processing flow sheets and reducing the costs
porated tectonic setting and physical and chemical characteristics of of producing copper. Placer Dome’s Zaldívar mine in Chile is an
the deposits (Cox and Singer, 1986; Roberts and Sheahan, 1988; example of a highly efficient and low-impact SX-EW plant and how
Sheahan and Cherry, 1993). In the 1990s, USGS geoenvironmental things can be done correctly (Richards, 2002). However, environ-
mineral deposit models (du Bray, 1995) were developed that provide mental problems with other SX-EW plants need to be worked out,
geologic information that can be used to better understand, predict, especially in finding ways to close the heaps without ongoing treat-
minimize, and remediate potential environmental effects of mineral ment of effluent. The increase use of in situ leaching and addition of
resources. Geoenvironmental models provide one method of devel- new in situ techniques would eliminate the need for moving tons of
oping site conceptual models and identifying potential environmental ore and waste to recover small quantities of marketable metals. But,
impacts based on characteristics of the mineral deposit. A geoenvi- once again proven technologies need to be improved with develop-
ronmental model is a compilation of geologic, geochemical, geo- ment of more environmental friendly lixiviants. Better techniques of
physical, hydrologic, and engineering information pertaining to envi- recycling mine wastes can open up new exploration opportunities
ronmental behavior of geologically similar mineral deposits prior to (Struther, 2000). The development of automated mining techniques
mining, and resulting from mining, mineral processing, smelting, and should allow access to new sources of underground ore.
refining (Plumlee and Nash, 1995). Today, geoenvironmental models
are receiving international support in the exploration industry and the INDICATORS
industry is demanding improved, more sophisticated geoenvironmen- Indicators are used to measure performance towards sustain-
tal models. Models of industrial minerals deposits are needed as well able development. Some of the suggested indicators for exploration
(Barker and McLemore, 2004). towards sustainable development are summarized below. These, and
Despite these advances in mineral deposit models, data is still others have been identified by the Sustainable Minerals Roundtable
needed about the processes of ore formation (Table 2; National (Shields et al., 2003) (www.unr.edu/mines/smr).
Academy of Sciences, 2002). Some of the data are company propri-
etary information and not readily available to others. Much of the data • The amount of land available for exploration and devel-
that is available (maps, production data, reserves, etc.) is in paper opment
form and would be costly to convert to digital form. • The number of exploration projects
Geophysical techniques reduce the physical impact of initial • Annual drilling footage or active drill rig count
exploration, and research in these techniques has been ongoing • Annual mineral leases
since the 1950s. Ground-based techniques such as gravity and seis- • The amount of dollars spent on exploration
mic surveys are costly and are being replaced by quicker, less • The number of new mines being developed
expensive aircraft and satellite surveys, such as magnetic, remote • Reserves/resources of specific commodities
sensing (Livo and Knepper, 2004), and hyperspectral surveys • Area reclaimed after exploration
(National Academy of Science, 2002). Better implementation and • Number of abandoned mines reclaimed during explo-
interpretation of these methods is needed (Table 2). ration
• The number of mines with production of materials as
Ultimately the deposit must be drilled in order to evaluate the
byproducts that might otherwise be considered waste
economic potential below the surface. The minerals exploration
(especially industrial minerals, such as clay deposits in
industry would benefit greatly by using newer drilling technologies
coal fields or porphyry deposits).
currently employed by the petroleum and geothermal industries, such
as directional drilling, horizontal drilling, and drilling tools. “Sump- LESSONS LEARNED
less” drilling, although more costly, reduces the risk of surface con-
tamination by drill products and is currently used by the petroleum Some lessons learned by exploration companies are summa-
industry and could be used in exploration for metals and industrial rized below.
minerals deposits (Richards, 2002). Bore-hole geophysical logging is
• The recognition of the role of stakeholders, including
a standard technique in the petroleum, geothermal, and coal indus-
indigenous cultures, in the decision-making process
tries; yet it is rarely used in other mineral exploration. These surveys
(Eggert, 2001). This requires the development and
measure the physical characteristics and differentiate rock types and
implementation of effective and open means of com-
could be used in many exploration projects. munication and regular engagement with the stake-
WHERE TO SPEND THE EXPLORATION DOLLAR? holders (for example, Molycorp’s Questa mine providing
reports online, www.molycorp.com).
As exploration budgets continue to shrink, new exploration tech- • A smaller, better-trained and efficient work force.
nologies will be used. Most exploration companies continue to focus • The recognition of the needs of local communities.
on known mineralized areas with a proven track record for land Some local people may value the land for its cultural
access and mineral development. The larger companies are diversi- and aesthetics and may be uncomfortable with any min-
fying into other commodities such as industrial minerals (Barker and ing, even if there is compensation (Richards, 2002).
McLemore, 2004).

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 SME Annual Meeting
Feb. 23-25, Denver, Colorado

Figure 1. Mine-Life Cycle Stages (Dirk van Zyl, written communication, March 27, 2002).

• Recognition that some areas are not acceptable for min- Conference Montreal, Quebec Montreal, Quebec, April 11, 2002.
ing (New World deposit near Yellowstone National Barker, J. M., and McLemore, V. T., 2004, Sustainable develop-
Park). ment and Industrial minerals: Society of Mining, Exploration, and
• Changes in mining methods to optimize and minimize Metallurgy, SME Preprint No. 04-** (this CD-ROM), 10 p.
cost of mineral development. Blench, R., 2001, Biodiversity issues: The enabling environment
• Mistakes made during the exploration period in not set- and mining: MMSD No. 60, IIED, 26 p.
ting up positive engagement with communities can Cox, D. P., and Singer, D. A., eds., 1986, Mineral deposit mod-
result in long-term problems in the development of new els: U.S. Geological Survey, Bulletin 1693, 379 p.
deposits. Downing, T. E., Moles, J., McIntosh, I., and Garcia-Downing, C.,
2002, Indigenous peoples and mining encounters: strategies and tac-
SUMMARY tics: MMSD No. 57, IIED, 41 p.
Mining is essential to meeting the needs of present society, Du Bray, E. A., ed., 1995, Preliminary compilation of descriptive
while contributing to a sustainable future. The challenge of explo- geoenvironmental mineral deposit models: U.S. Geological Survey,
ration and mining in the future is to develop superior exploration and Open-file Report 95-831, 272 p.
resource characterization methods and to develop better technolo- Eggert, R. G., 2001, Mining and economic sustainability:
gies to find and define larger high-grade reserves with minimal envi- National economics and local communities: MMSD No. 19, IIED, 84
ronmental disturbance. New mining and processing techniques also p.
can provide for additional exploration targets in the future. Exploration Hartman, H. L., 1992, Introduction to mining; in Hartman, H. L.,
can be compatible with environmental protection and social respon- ed., Mining Engineering handbook: Society for Mining, Metallurgy,
sibility, but difficult challenges face the industry to develop a property and Exploration, Inc., Littleton Colorado, p. 3-42.
that is environmentally, economically, and socially responsible. Horswill, D. H. and Sandvik, H., 2000, Mining and sustainable
development at Red Dog: Mining Engineering, v. 52, no. 11, p. 25-31.
ACKNOWLEDGEMENTS Livo, K. and Knepper, D., 2004, Non-invasive exploration in an
Comments by James Barker and Dirk van Zyl on an earlier ver- environmentally sensitive world: Society of Mining, Exploration, and
sion of this manuscript are appreciated. Metallurgy, SME Preprint No. 04-** (this CD-ROM), 8 p.
McLemore, V. T., Russell, C. C., Smith, K. S. and the Sampling
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