Description:
Mineral production is essential to our civilization because minerals provide the raw materials which
allow our society to function. Pima County is endowed with many mineral resources, not only copper
mines, but also the important products such as sand, gravel, and limestone used everyday in
supporting the infrastructure of our cities. It is essential that these mineral resources, and the lands
where they occur, remain available for exploration and development.
Mining is a significant part of Pima County’s economy. Last year, copper producers bought $186
million worth of goods and services from Pima County firms. Local governments in the Tucson
Metropolitan area received $10 million in direct tax payments. Residents received over $88 million in
personal income directly from the copper industry. When revenue from other mining operations and
the economic multiplier effect of expenditures is taken into account, the real value of mining is nearly
five times greater than these numbers.
This report presents an assessment of the mineral resources of Pima County based on hard data
derived from many experienced geologists working in the private sector and from publications of state
and federal government agencies.
Pima County has a unique, and complex, geological history which makes it critical habitat for large
copper deposits, geothermal resources, and many industrial minerals such as sand, gravel, gypsum,
and limestone. This report documents known occurrences of these mineral deposits, and delineates
areas with the greatest potential for future discovery of additional mineral deposits, based on existing
geological and geochemical data, and upon proven methods of investigation.
Most areas favorable for mineral deposits coincide with portions of the Sonoran Desert Conservation
Plan’s proposed biological reserves. We should note that mineral exploration and production is not
necessarily incompatible with conservation. The Sonoran Desert Conservation Plan addresses six
elements: ranching, historical and cultural preservation, mountain parks, riparian protection, critical
and sensitive habitats, and biological corridors. An important seventh element is missing: mineral
resources.
This report outlines seven areas which are critical habitats for undiscovered mineral deposits, areas
which need to be as carefully protected and defined as are habitats for endangered species. If these
prospectable areas are withdrawn from exploration and development, the availability of our future
sand and gravel, porphyry copper deposits, and other mineral deposits will become endangered and,
in a real sense, the availability of vital minerals will eventually become extinct in Pima County. The
impact of such a development on Pima County and the Tucson Metropolitan area will be
considerable. If the sand and gravel deposits can no longer operate within a reasonable distance of
construction sites, the costs of new construction and of renovations of existing infrastructure will
greatly increase. Although the direct impact of curtailing copper exploration and development will not
be immediately noticeable to most citizens of Pima County, the longer term impact could affect the
cost and availability of many common products we use today, and also could be detrimental to the
future national security of the United States.
Members of the Southwestern Minerals Exploration Association strongly recommend that the
potential mineral bearing areas be kept available for future development, and urge the planners of the
Sonoran Desert Conservation Plan to consider minerals as a critical Seventh Element in the planning
process - an element that needs protection as much as many of the “vulnerable” species being
considered.