Keweenaw Peninsula EarthCaches 

Gay Sands – The Happiest Place on Earth? 

Connection to the Earth Science Curriculum

Essential Lessons:

How have the stamp sands effected this environment?

What has caused the stamp sands to move down the shoreline?

Earth Science Literacy Principles

#4 Earth is continuously changing.

#9 Humans significantly alter the Earth.

Common misconceptions

Earth was always the way it is now.

Earth and its systems are too big to be affected by human actions.

Michigan State Science Content Expectations Addressed

K-7 Standard E.SE: Develop an understanding of the properties of Earth materials and how those properties make materials useful. Understand gradual and rapid changes in Earth materials and features of the surface of Earth. Understand magnetic properties of Earth.

Grade 6: E:SE.06.12 Explain how waves, wind, water, and glacier movement, shape and reshape the land surface of the Earth by eroding rock in some areas and depositing sediments in other areas


Alluvial fan – a fan shaped deposit of material, (you will notice these along the cliffs as you continue through the cache). This fan shaped deposit is caused by moving water, most often from streams, but in this case by high waves from Lake Superior during storms.

Coriolis Effect – due to the Earth’s rotation, air circulating in the Northern Hemisphere deflects to the right, and in the southern hemisphere the atmosphere deflects to the left. Wind is one of the main factors that determine current in Lake Superior. The Coriolis Effect causes the current to carry sediment southwest down the shoreline at Gay.

Launder – a long trough that works like a drain to take the slurry of waste rock away from the stamp mill to where it is discarded, in this case Lake Superior.

Longshore Drift – where waves approach a shoreline at an angle. The energy of the wave pushes material along the beach up the shoreline at the same angle. The backwash of the wave pulls sediment back perpendicular to the shore, creating a zig-zag movement of beach material along and down the shore.

Ore rock – rock from copper mines that contains a valuable amount of copper.

Poor rock – rock from the copper mines that did not contain large amounts of copper. As technology improved, this poor rock was taken to stamp mills where it was crushed to get out the remaining copper. The more dense copper could be separated from the rest of the rock by crushing the rock, then passing the crushed rock mixed with lots of water through machines to separate the copper out and let the waste rock continue to the dump site.

SITE VISITED: July 14, 2011

Along the coast of Lake Superior at the town of Gay, Michigan is an area known as the Gay Sands. This is an area that was created due to the two stamp mills that were operating in Gay. Essentially two things came out of the copper mines, pieces of rock that had copper in them (ore rock) and rock that didn't have enough copper in them to be considered valuable (poor rock). The function of the stamp mills was to get to separate the copper from the rock. This rock was stamped (crushed) to extract the copper. Water was then used to separate the copper from the rock. The more dense copper would sink to the bottom while the water would carry the less dense rock away. The copper was sent to a smelter and anything left was dumped in the nearby lake or river. The stamp mills were often built near rivers or streams because they needed a lot of water (about 30 tons of water for each ton of ore that was stamped). Another benefit for building near a river or lake was the waterway could be used for transportation, getting fuel in and transporting ore out. For over 30 years, every day, the two stamp mills in Gay, Michigan dumped thousands of tons of stamped waste rock into Lake Superior. With time, this waste rock began to create a new shoreline and it continued to grow each year the mills operated. At the time there were not thoughts about what this might do to the environment, like there would be today. This area that was created by the dumping of stamp mill waste is known as the Gay Stamp Sands and covers around 350 acres.

This cache will take you on a short exploration of this area. There are heavy metals present in the sand like arsenic, although we were told it isn't harmful to humans to be on the sands (we walked all over it and there is evidence that many other people have been here as well), but the first thing you probably noticed is that there is a lot of nothing here in terms of plant life.

Figure 1. Gay Stamp Sands. Gay Sands beach. D. Wagner

Difficulty – 2

Terrain – 1.5


Start Point: N 47° 12.100′ W 88° 10.256′

This is an entrance to the sands.

Stop 1 – When you enter here you will notice a small, numbered, diamond-shaped orange sign nearby. What number is on the sign?

Figure 2. Poor rock pile. Located a few miles away at Mohawk Mine. D. Wagner

Figure 3. Gay Sands. Alluvial Fans at Stamp Sands. D. Wagner

Stop 2 – N 47° 13.137′ W 88° 10.117′

Log Questions #2: As you get to this area, look around at the landscape. To the north you will see some small shrubby plants. Why do you think these plants are growing here? Compare and contrast the area these plants are located to the other areas around you.

As you make your way to stop 3 you will see the cliffs of stamp sand with many alluvial fans along the base.

Within the past two years (summer of 2009-2011) 150 feet of the shore line has been moved away due to longshore drift. This movement of the stamp sand had caused a lot of concern for those that live down the coast. About four miles down shore near the Traverse Bay Harbor is Buffalo Reef, a spawning area for trout and white fish. This reef has been compromised due to the stamp sands that have made their way out to this area. This has impacted fishing in the area near Grand Traverse Bay. A breakwater has been built here to try to keep the stamp sand from progressing any further along the coast. The stamp sand has breached the breakwater and made its way into the canal, but so far the stamp sand has not made it to the other side of the break water (summer of 2011).

Stop 3 – N 47° 13.137′ W 88° 9.541′

Log Question #3: What evidence do you see that indicates humans put these sands here, rather than a force of nature?

If you continue a little further along the shoreline you will come to a concrete launder that is marked with the year 1915. Once the ore rock was stamped, it was mixed with water to create a slurry. The more dense copper would settle the bottom thus separating it from the rest of the rock. The slurry with waste sand was sent down the launder and emptied into Lake Superior. The evidence of longshore drift continues to the south along the shore for about 4 miles. Once you get to what is left of the concrete launder, you can see a difference between the shoreline north of the mill area and the southwest, where you have just been walking. The reason the area northeast of this point is not as affected by the stamp sands is due to the Coriolis Effect.

Figure 4. Gay Sands. Concrete launderer. D. Wagner

Figure 5. Lake Superior beach. Looking northeast from concrete launder. D. Wagner

Figure 6. Gay Sands. Looking southeast of concrete launder. D. Wagner

ACCESS INFORMATION: Property owned by County Road Commission.


Schaetzl, Randall J., Darden, Joe T., and Brandt, Danita S. Michigan Geography and Geology. New York: Custom, 2009. Print

(July, 2011). Keweenaw Free Guide.
Retrieved from Copper Country Explorer

(July, 2011). Coriolis.
Retrieved from MiTEP ESI-1

(July, 2011). Stamp Sands.
Retrieved from MiTEP ESI-1

W. Rose. Personal Interview. 14 July, 2011