Tuesday, July 22, 2014

Alaska Adventure–Day 18 (Part 1)

Fairbanks, AK

Today was a very busy day - with a visit to Gold Dredge 8, the Trans Alaska Pipeline, and the River Boat Discovery, so we will break the day into two parts.

This morning we woke to the sound of rain, which was not a welcome sound since we had outdoor activities planned for the whole day.  Luckily, the rain stopped and it turned into a fairly nice day.  Our first stop was for a tour of Gold Dredge 8 which is a dredge that was operated by the Fairbanks Exploration Company from 1928 to 1959.  During its years of operation, it produced 7.5 million ounces of gold!  Basically, to form the mine they removed the top layer of soil to get down to gold bearing rock and then they dug a pit which was filled with water.  The dredge floated on the water and chewed up the banks of the pit, sifting through tons and tons of rock to extract the precious gold flakes.

For the tour, we rode on an old train with various stops where the different steps in the mining process were described and re-enacted.  We then had the opportunity to tour the dredge itself.  Of course, the highlight of the tour was at the end where they gave us a poke of pay dirt and a gold pan to extract any gold that we might find.  After you extracted the gold, they weighed it and told you what it was worth.  Between the two of us we found about $16 of gold. 

We found the tour to be extremely interesting and a very good value, and would highly recommend it.  The tour cost $40 each but with the TourSaver book, the price was cut in half.

View of the dredge.  The pay dirt enters on the right and the tailings exit on the right. 



Ready to do some gold panning!


Starting to see a few flakes of gold emerge from the gravel.  Gold Fever!




Big tough safe for the gold


The tour also had numerous historical items around the dredge (not including Valerie!).


After striking it rich panning for gold, we stopped to visit the Trans Alaska Pipeline -which is what has made Alaska what it is today.  The pipeline, which was built between 1974 and 1977, moves oil from the rich oil fields on the north slope near Prudoe Bay, to the tanker terminal in Valdez 800 miles away.  It takes almost 12 days for the oil to make the complete 800 mile trip.  From the terminal, the oil is shipped to the lower 48 where it currently supplies about 10% of our needs.  The pipeline has drastically changed the economy of Alaska.  Before the pipeline was built, Alaska had the highest taxes of any state in the union.  Today, as a result of the oil income, Alaska has the lowest taxes of any state.  They have no income tax and no sales tax.  In addition, each Alaskan received a check for nearly $900 last year as their share in the oil revenue.


A view of the pipeline just north of Fairbanks.  Almost half of the 800 mile pipeline is built above ground to prevent the warm oil from melting the permafrost, which turns to liquid when melted. 


Notice the two fin shaped objects on the top of the pipeline stands.  These are radiators that prevent heat from melting the permafrost.  The upright structures have ammonia that passively circulates to the radiators to reject any heat before it can reach the permafrost.


A close up view of the radiators


As the oil moves through the pipeline it deposits wax and other precipitates along the sides, which over time would cause big problems.  To solve this problem, pipeline Pigs - as shown below - are passed through the line every couple weeks.  The pigs have scrapers that remove any buildup on the inside of the pipe.


In addition to using scraper pigs in the line to clean it, they also send “smart pigs” through the line to electronically inspect the line.  The inspection looks for thin spots, cracks, deformations, and other defects.  By doing periodic inspections of the line, they have avoided any major leaks in over 35 year of operation.  Remember the big controversy over the welds and questionable x-rays during the construction?


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