Page 114 - Laboratory Manual in Physical Geology

What Are Conflict Minerals? all coltan from DRC as a “conflict mineral.” It is illegal
to import any coltan, niobium, or tantalum into the
Niobium (Nb) and tantalum (Ta) are two rare metallic
United States if it originated in the DRC or another
mineral resources (metal elements). Niobium (for-
conflict-mineral site.
merly called columbium) is mixed with iron to make
high-strength non-corrosive steel alloys (for rockets,
jet engines, chemical pipelines, nuclear power plants) How Ores and Precious Metals Are
and superconducting magnets for medical MRI scan- Weighed
ners. Tantalum is used to make alloys with high heat Did you know that it is common practice in the United
tolerance for electronic microchips (for small electri- States to weigh gold and its ore using different systems of
cal devices like cell phones) and non-irritating steel measurement? Within the United States, mining com-
for surgical steel tools. Niobium is refined from the panies use an avoirdupois system to weigh bulk amounts
mineral columbite, and tantalum is refined from the of rock like gold ore —material (usually rocks or miner-
mineral tantalite. The two minerals commonly occur als) from which chemicals can be extracted at a profit. If
together as an ore called “coltan.” Unfortunately, a they sell the gold ore to another country, then its weight
primary source of coltan is the Democratic Republic of is quoted using the metric system (page xiii at the front
Congo (DRC) in Africa, where rebel groups use forced of the manual). However, once gold is extracted from its
labor to mine the coltan and engage in extreme violence ore, its weight is quoted everywhere in the world using the
against women and children. The United States regards troy system.

Grams Are Metric; Ounces Are Not
A gram is a metric unit of weight (mass) equal to one
thousandth of a kilogram—roughly the mass of a paper
clip. Any metric scale or balance can be used to measure the
weight (mass) of an object in the metric unit called a gram.
ACTIVITY However, there are no metric ounces. Ounces are used in
the avoirdupois and troy systems of measurement. An avoir-
3.6 Urban Ore dupois ounce is 28.349523125 grams, and a troy ounce is
31.1034768 grams. Also, note that fluid ounces are units of
THINK How sustainable is your dependency volume, not weight.
About It on minerals and elements extracted
from them? What Is Avoirdupois?
Avoirdupois (avdp) is pronounced in English as
OBJECTIVE Evaluate the prospect of recycling “aver-due-pois,” with the “pois” as in poison. It refers
products and mining discarded products to extract to a system of weights (masses) that is widely used
their metals. in the United States, and parts of Canada and Great
Britain, to weigh everything except precious metals,
PROCEDURES
gems, and pharmaceuticals (drugs). It is based on a
1. Before you begin, read the background 28.35-gram ounce (oz), 16-avdp-ounce pound (lb),
information ahead. You must also obtain access to and 2000-pound short ton . The concept of a pound
a computer that has Internet access. This is what originated in the Roman Empire, developed into a
you will need to bring to lab: 16-ounce pound in Europe by the year 1300, and
___ Activity 3.6 Worksheet (p. 110 ) and pencil was the system of weights adopted by the 13 British
___ calculator Colonies that became the United States of America.
2. Then follow your instructor’s directions about However, the United States developed the 2000-pound
how to complete the worksheet. “short ton” that is still used today (instead of the
British 2240-pound “long ton”).

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