Page 129 - Laboratory Manual in Physical Geology

A CTIVIT Y 3.6 Urban Ore

Name: ______________________________________ Course/Section: ______________________ Date: ___________

A. Recall that “ore” is a material (usually rocks or minerals) from which chemicals can be extracted at a profit.

1. More than half of the gold mined in the U.S. is from mines in northern Nevada. These mines produced an average of
3.2 grams of gold per 2000-pound short ton of ore in 2012.

a. Search the Internet for “New York spot gold price” in U.S.
dollars (USD) per ounce, and enter it here. Note that ounces NY spot gold price: ______________________
of gold are always quoted in troy ounces (ozt), but some
people incorrectly report it as “oz.”
b. There are 31.1 grams (g) in one troy ounce (ozt). How many

troy ounces of gold are extracted from one short ton of average
Nevada ore? Show your work.

c. What is the gold worth (in USD) from one ton of the Nevada

ore? Show your work.

d. It costs about $640 to extract 1 troy ounce of Nevada gold from

the mine. So how much does it cost to mine and extract the gold
from one short ton of the Nevada ore? Show your work.

e. Based on your answers in c and d above, what is the current
average profit per ton of gold ore from northern Nevada?

B. The average iPhone 5 contains 0.0012 grams of gold and weighs 3.951 ounces (avdp).

1. There are 16.00 ounces in one avoirdupois pound and 2000 pounds
in one short ton (avoirdupois ton). How many iPhone 5 cell phones
are there in one short ton? Show your work.

2. Based on your work above, and the fact that there are about 0.0012
grams of gold in one iPhone 5, how many grams of gold are there in
one short ton of iPhone 5 cell phones? Show your work.

3. There are 31.1 grams in one troy ounce. How many troy ounces of

gold are there in 1 short ton of iPhone 5s? Show your work.

4. Based on the New York spot gold price in USD per troy ounce)

that you determined above (part A1a ), what is the current value of
the gold in one short ton of iPhone 5 cell phones?

C. REFLECT & DISCUSS What materials besides cell phones could the U.S. recycle or mine as “urban ore” for metals noted

in FIGURE 3.22 , and what impact would this have on the environment and the ability of the U.S. to sustain its need for metals

and mineral ores?

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