Found: Middle Grade book published before 1960

When I was in middle school, my school library had a sale of books published before 1960. The book I'm looking for was in a bin with titles such as "Skating Shoes" and "Marcia, Private Secretary." It had generic yellow binding, so I'm afraid the cover art won't be helpful.

The title on the generic binding was "Redhead" but so far that hasn't produced fruit. What I remember of the book is that the main character's name was Susie or Suzie. She had a little sister named Brenda. She lived in a defunct mining town and her family was among the last to leave. There was the son of the grocery store owner, Ned, for her to spend her days with. She had an ex-best friend named Connie. Her grandmother was very harsh and was referred to as a "blitzkrieg" by a neighboring woman. Some other characters were Robin and Tracy or Tracey, whose family owned Clear Lake. There was a salt marsh. Susie had a temper. She had been wanting to be initiated into a secret club called Tau Nu Tau and had been passed over before the explosion that caused the mine to shut down. Connie's cat came to live with Susie, and eventually Robin's family hired Susie's dad so they could stay in the area.

I would love to find this book. I have googled the bejesus out of it and even placed a call with a local library.

Redhead by Jean Nielsen? No description here, but Goodreads mentions a mining ghost town.

>2 keachachu: Here's the link to the Goodreads Page by the way: https://www.goodreads.com/book/show/23494492-redhead

That's the one! Thank you so much!