Homework 6

222 CHAPTER 8 DECIDING THE COURSE OF ACTION EXERCISES

• History 201 U.S. History: Civil War to Present, 3 hours

• Art 203 Photography, 3 hours

• Geology 101 Introductory to Geology, 3 hours

• Music 205 Piano Performance, 2 hours

Music 101 involves a significant amount of time outside of class listening to classi- cal music. The student reaction to the class has been mixed; some students learned what to listen for in a symphony, while others did not. The teacher for this class is knowledgeable but boring.

Art 101 has the students learning the names of the great masters and how to recog- nize their works. The lecturer is extremely boring and you must go to class to see the slides of the great art works. While the course write-up looks good, it misses the mark in developing a real appreciation of art. However, it is quite easy to get a rela- tively good course grade.

History 201 has an outstanding lecturer that makes history come alive. However, the lecturer is a hard grader and C is certainly the median grade. In addition, the outside reading and homework are enormous. While some students say the workload is equivalent to a five-hour course, most all say they learned a great deal from the course and plan to continue the interest in history they developed during this course.

Art 203 teaches the fundamentals of photography. However, equipment and film for the course are quite expensive. Most of the time spent on the course is outside of class looking for artistic shots. The instructor is very demanding and bases his grade on artistic ability. Some students say that no matter how hard you work, if you don't develop a "photographic eye," you might not pass the course.

Geology 101 has a moderately interesting lecturer and there is a normal level of homework assignments. There are two major out-of-town field trips that will require you to miss a total of one week of class during the term. The average grade is B and there is nothing conceptually difficult or memorable about the course.

Music 205 requires you to pass a tryout to be admitted. While you only spend half an hour a week with your professor, many, many hours of practice are required. You must have significant talent to get a C or better.

Prepare a K.T. decision analysis table to decide which course to enroll in.

8.10. "The Centralia Mine Fire": Centralia, Pennsylvania, a small community situated in the Appalachian mountain range, was once a prosperous coal-mining town. In 1962, in preparation for the approaching Memorial Day parade, the landfill of Centralia was set afire in order to eliminate odors, paper buildup, and rats. Unfor- tunately, the fire burned down into the passageways of the abandoned mine shafts under the town. Although repeated efforts were made to stop the blaze, the fire

could not be put out. By 1980, after burning for 18 years, the fire had grown in size

to nearly 200 acres, with no end in sight.

Mine fires are especially difficult situations because they are far below the surface

of the earth, burn very hot (between 400°F and 1000°F), and give off both toxic and

explosive gases, as well as large volumes of steam when the heat reaches the water

table. Anthracite coal regions have very porous rock, and consequently, a signifi-

cant amount of combustion gas can diffuse directly up through the ground and into

people's homes. Subsidence, or shifting of the earth, is another serious condition

arising from the fire. When the coal pillars supporting the ceilings of mines' pas-

sageways burn, large sections of earth may suddenly drop 20 or 30 feet into the

ground.

Clearly, the Centralia mine fire has very serious surface impact and must be dealt

with effectively. Several solutions to the mine fire are described below. Perform a

K.T. decision analysis to decide which option is the most effective method to deal

with the fire. Consider such issues as cost, relocation of the residents of Centralia,

and potential success of extinguishing the fire.

Solution Options

A. Completely excavate the fire site. Strip-mine the entire site to a depth of 435 feet, dig-

ging up all land in the fire's impact zone. This would require partial dismantling of

Centralia and nearby Bymesville for upward of 10 years, but available reclamation

techniques could restore the countryside after this time. This method guarantees

complete extinction at a cost of $200 million. This cost includes relocation of fami-

lies, as well as the restorative process.

B. Build cut-off trenches. Dig a trench to a depth of 435 feet, then fill it with a clay-based

noncombustible material. Behind the trench, the fire burns unchecked but is con-

tained by the barrier. Cost of implementation would be about $15 million per 1000

feet of trench, and total containment of the fire would require approximately 7000

feet of trench. Additionally, partial relocation of Centralia would be required for three

years, costing about $5 million.

C. Flood the mines. Pump 200 million gallons of water per year into the mine at a cost of

$2 million annually for 20 years to extinguish the fire. Relocation of the townspeople

is not necessary, but subsidence and steam output should be considered, as well as the

environmental impact and tradeoffs of the large quantities of acidic water produced

by this technique.

D. Seal mine entrances to suffocate the fire. Encase the entire area in concrete to seal all

mine entrances, then allow the fire to suffocate due to lack of air. This would require

short-term relocation of the town and its outlying areas, and suffocation itself would

probably take a few years, owing to the large amount of air in the shafts and in the

ground. Although this method has never been attempted, the cost is estimated to be

about $100 million.

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