Is there a reason why some is in circles and some in squares ?
Yes, I think there was a difference, if the boxes or the circles turn out to be more for veins/hardrock gold, then the other type markings (either box or circles) should be better for placer deposits. Also some copper ore contains gold and platinum, which can make dowsed signals seem different. You'll really need to check and see what is there.
I'd check the circles first, I'm thinking the hits on those had more prospecting potential, but it was hard to tell for sure. I dowsed some GE maps once for someone in Zimbabwe. a country in S Africa. To understand the signals, had to search for info. The GE maps included the Falcon mine. The country has a lot of copper mining with gold and especially large amounts of platinum.
"The mining industry in Zimbabwe is well developed and evidence of early mining in the country goes back thousands of years. Ownership of current mining operations includes a range of small to medium domestic private companies, four large locally listed mining Companies (Bindura Nickel, HwangeColliery,
Falcon Gold and RioZim) and a number of large international mining and international cement companies.Thestate is directly involved in mining. The Zimbabwe Mining Development Corporation (ZMDC has equity interests in inactive copper mining and processing facilities and gold mines. ZMDC has also been assigned the Marange diamond mining operation in eastern Zimbabwe, currently in dispute. Subsidiaries of the state-owned Industrial Development Corporation of Zimbabwe produce industrial minerals and mineral-based commodities, including clay, fertilizers, glass, phosphate rock, and stone. Zisco, in which the Government holds a majority interest, operates a crude steel plant, and aZisco subsidiary operates iron ore and limestonemines.Foreign investment is concentrated in the cement, chromium, coal, diamond, gold, nickel, PGM, and steel sectors."
Since you are located in S Africa, might be good to research the different types of gold geology found in your area (if you haven't already).
Here is a minig link.
Zimbabwe's largest platinum mine agrees to sell shares to gov't under black empowerment laws | Fox News
For prospecting you need to have places where coarse gold is found, hopefully there are some in your maps.
