Computercraft gravel protected dig() function

function mine()
turtle.dig()
function gravel()
if turtle.forward() == false then
                repeat
                turtle.dig()
                sleep(0.25)  -- small sleep to allow for gravel/sand to fall.
                until turtle.forward() == true
                end
end
gravel()
turtle.digUp()
end
function mine2()
turtle.dig()
function gravel()
if turtle.forward() == false then
                repeat
                turtle.dig()
                sleep(0.25)  -- small sleep to allow for gravel/sand to fall.
                until turtle.forward() == true
                end
end
gravel()
end