simple mine

turtle.select(16)
turtle.refuel(4)

for i2=0,1 do

for i1=0,64 do
turtle.dig()
forward()
turtle.digUp()
turtle.digDown()
end

turtle.turnRight()
turtle.dig()
forward()
turtle.digUp()
turtle.digDown()
turtle.dig()
forward()
turtle.digUp()
turtle.digDown()
turtle.dig()
forward()
turtle.digUp()
turtle.digDown()
turtle.turnRight()

end