Gay Sands

Gay Mill Site

Original Stamp Sand fan ~1935, eroded back hundreds of meters since


Redistributed and redeposited Stamp Sands 1000 m west of Gay

Stamp Sands

                   Gay Sands impression

                    Stamp Sand Defined

                    Stamp Mill in Operation (You Tube)

                    What are tailings?

                    Safety of Tailings dams

Reports and Articles

            Gay Sands Movement

            Keweenaw Current

            Cu, Hg in Lake Superior

            Keweenaw Current Van Luven


            Kerfoot illustrations

To separate minerals from a rock, the rock is usually crushed. One way to crush is to break the rock by stamping it with force.  The idea is to “liberate” the minerals by reducing the grain size of the rock to the size of the minerals. This typically requires a lot of energy and equipment at a stamp mill.  So at the mine, the rock is broken only enough to get it into an ore car. At the mine site, poor rock is separated from ore.  The ore is then transported to the stamp mill, often miles away (Gay is about 11 miles from Mohawk).  At the mill the rock is crushed to a fine size, in order to separate the minerals.  Copper is much heavier than other minerals so it can be separated by gravity.  Stamp mills are often near the shore because they can get fuel to run the mill by boat, and they can ship the ore by boat. After the stamp mill mineral separation there is a lot of waste rock which is sand and silt size---this is the stamp sand. It was dumped in the lake.
Because of Coriolis counterclockwise currents operate in large lakes like Superior.  The Keweenaw Current moves to the Southwest across the Gay shoreline, carrying stamp sand with it. The fan of tailings in Lake Superior is steadily migrating along the shore and has reached the breakwater at Traverse Bay about 4 miles SW of the stamp mill. Homes that were on the beach are now far away from it.

There is arsenic in the Gay sands.  This is known from the mineralogy of the Mohawk mines, which all contained significant arsenides.  Whenever toxic materials are present at the surface they should be evaluated and investigated as possible threats to water quality.

Links about Arsenic in Environment

Discover 2013

Any As in your environment may be a potential problem.


EPA web page providing information on arsenic in drinking water


UN Food and Agriculture Organization web age with information on arsenic contamination


USGS web page on Arsenic in groundwater in the US


WaterAid pdf file on Arsenic in Bangladesh (also found on web page list of water quality data sheets)


World Health Organization web page providing information on arsenic in drinking water

Citizen scientists! Take charge of water quality issues.  Any citizen may request water quality analyses.  Many analyses are performed at no charge.  In every region there are regional drinking water testing labs.  In Houghton there is one on the MTU campus (MDCH Upper Peninsula Laboratory Ms. Patricia Wheeler P.O. Box 38 Houghton, MI 49931 Phone:(906) 482-3011 Fax:(906) 482-7550 Email:  Last summer we submitted three water samples from the Gay and Torch Lake Sands for Arsenic analyses:


Gay Sands, sample 1

collected about 4 feet from large pool on stamp sands where we did the trash pump/ alluvial fan experiment. Shallow pit was dug to let water accumulate, water was collected in a plastic cup and filtered through an unbleached coffee filter to help remove some of the suspended sediment.


Gay Sands, sample 2

From near small yellowish pond on stamp sands near where we parked. Small pit was excavated about 2 feet from the pond's shore, sample was skimmed off the top of the water that collected in that pit to help avoid excess sediment.


Torch Lake, sample 1

Water sample collected at inlet right near old dredge. A small hole was dug, water was allowed to collect and settle before collection.

Results of the analyses are here. These results show clearly that As is being leached from the Gay sands.  This matter should be better understood.

Coriolis Effect

                    Animation of the Coriolis effect

                    Coriolis Home Page

                    Bad Coriolis

                    Numerical Modeling of Lake Currents

                          Coriolis (WIKI)

Air Photo Time Series





Big Traverse

Stamp Sand Transport by currents

Park Here
Distal Stamp Sand
Redistributed Stamp Sand
Gay Stamp Mill
Eroded Stamp Sand Fan
Eroded Scarp of Stamp Sands
Tobacco R Park


Alex Guth

At the Tobacco R Park, there are interesting outcrops of Jacobsville Sandstone showing channels and cross bedding.  These demonstrate the alluvial streams of the rift filling sequence of red beds.

Alex Guth Photo

Source: Keweenaw Buffalo Reef
Kerfoot et al., 2012

Shoreline exposure of Jacobsville at Tobacco R Mouth

David Kelly