Digging Cactus in Arizona

The Arizona Sonoran Copper Company’s [Cactus Mine](https://arizonasonoran.com/projects/cactus-mine-project/overview/) near Casa Grande, AZ, presents its spiral down into the Earth in this 25cm resolution high resolution topographic model. As inspiring as it is here, note that the company’s logo is indeed a spiral icon. I suspect it was inspired by the mine’s circular shape. The hole is about 280 meters deep at the time the LiDAR was flown, and has a diameter of roughly 900 meters. The elevation values are mapped here to a cyclic color palette that repeats every 10 meters. With some diligence, you can count the “blue” stripes from the bottom to the top, each step being 10 meters. The color of the water surface at the bottom of the hole is only coincidentally “blue”, as it sits at ~160 meters above sea level, a multiple of 10 meters. USGS LiDAR dataset “AZ_MaricopaPinal_2020_B20” was used to produce the image in Global Mapper, rendered as an ECW raster image.