Found the problem. Author renamed the mod. Go into your mod directory
%appdata%/Factorio/mods
Copy "Gold_Mining_1.1.0.Zip" to your desktop
Delete the mod from Factorio so its un-associated, using the INGAME tool. If you just delete the file it will not work.
Unzip the copy you made to your desktop so you have a "Gold Mining 1.1.0" folder on your desktop.
Open said folder, and find the "Info.Json" file and right click on it, open with Notepad or Notepad++. DO NOT USE WORD OR MICROSOFT WORD!
Change the name field from
"name": "Gold_Mining",
to
"name": "GoldMining",
and save.
Delete or rename the old Zip file.
Rezip the folder, you should get a file name like "Gold Mining 1.1.0.zip". Rename the file to be "Gold_Mining_1.1.0.zip". If you skip this step it will not work.
Drop the new File you just renamed into the Factorio mods folder, launch the game, select the mod to load in the menu screen, and enjoy.