why my ores dont spawn on locations??

Try this:

local rock = script.Parent.Rock:Clone()
local rockLocations = game.Workspace.RockLocations:GetChildren() 
local numLocations = #rockLocations

rock:Destroy()

for place = 1, numLocations - 1 do 
    local rockClone = rock:Clone() 
    rockClone.Parent = script.Parent 
    rockClone.Position = rockLocations[place].Position 
    rockLocations[place].Free.Value = false 
end

all I've done is cloned the reference rock and used that clone for your rockClone variable. It looked like the code was spawning the rocks at your locations but then deleting them right after, So cloning the reference part makes a fresh/stand-alone copy of the reference part.

Hope this helps! :)