Works

while true do
  local i = turtle.getFuelLevel()
  if  (i < 200) and (i < 1000) then
    turtle.refuel(1)
  end
  turtle.forward()
  turtle.turnLeft()
  for j = 1, 100 do
    if turtle.detectDown() then
      if turtle.detect() then
        turtle.dig()
        turtle.forward()
        j = j + 1
      else
        turtle.forward()
        j = j + 1
      end
    else
      turtle.down()
    end
  end
  for k = 1, 50 do
    if turtle.detectDown() then
      turtle.dig()
      turtle.digDown()
      turtle.down()
      turtle.dig()
      turtle.forward()
      turtle.turnLeft()
      k = k + 1
    else
      turtle.down()
      turtle.dig()
      turtle.digDown()
      turtle.down()
      turtle.dig()
      turtle.forward()
      turtle.turnLeft()
      k = k + 1
    end
  end
  local x, y, z = gps.locate()
  yDif = y + 1
  zDif = z - 252.62
  xDif = x + 3.94
  if yDif < 0 then
    if turtle.detectUp() then
      turtle.digUp()
      turtle.up()
    else
      turtle.up()
    end
  end
  if yDif > 0 then
    if turtle.detectDown() then
      turtle.digDown()
      turtle.down()
    else
      turtle.down()
    end
  end

  local xx, yy, zz = gps.locate();
  xDif2 = xx - x
  zDif2 = zz - z
  if xDif2 > 0 then
    if zDif < 0 then
      turtle.turnLeft()
      while zDif < 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif - zDif2
        else
          turtle.forward()
          zDif = zDif - zDif2
        end
      end
    end
    if zDif > 0 then
      turtle.turnRight()
      while zDif > 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif + zDif2
        else
          turtle.forward()
          zDif = zDif + zDif2
        end
      end
    end
  end
  if xDif2 < 0 then
    if zDif < 0 then
      turtle.turnRight()
      while zDif < 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif - zDif2
        else
          turtle.forward()
          zDif = zDif - zDif2
        end
      end
    end
    if zDif > 0 then
      turtle.turnLeft()
      while zDif > 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif + zDif2
        else
          turtle.forward()
          zDif = zDif + zDif2
        end
      end
    end
  end
  if zDif2 > 0 then
    if zDif < 0 then
      turtle.turnLeft()
      turtle.turnLeft()
      while zDif < 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif + zDif2
        else
          turtle.forward()
          zDif = zDif + zDif2
        end
      end
    end
    if zDif > 0 then
      while zDif > 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif - zDif2
        else
          turtle.forward()
          zDif = zDif - zDif2
        end
      end
    end
  end
  if zDif2 < 0 then
    if zDif < 0 then
      while zDif < 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif - zDif2
        else
          turtle.forward()
          zDif = zDif - zDif2
        end
      end
    end
    if zDif > 0 then
      while zDif > 0 do
        if turtle.detect() then
          turtle.dig()
          turtle.forward()
          zDif = zDif + zDif2
        else
          turtle.forward()
          zDif = zDif + zDif2
        end
      end
    end
  end

  turtle.turnLeft()
  local x3, y3, z3 = gps.locate()
  turtle.forward()
  local x4, y4, z4 = gps.locate()
  xDif3 = x4 - x3

  if xDif3 < 0 then
    turtle.turnLeft()
    turtle.turnLeft()
    while xDif3 < 0 do
      if turtle.detect() then
        turtle.dig()
        turtle.forward()
        xDif3 = xDif3 - xDif3
      else
        turtle.forward()
        xDif3 = xDif3 - xDif3
      end
    end
  end
  if xDif3 > 0 then
    turtle.turnLeft()
    turtle.turnLeft()
    while xDif3 > 0 do
      if turtle.detect() then
        turtle.dig()
        turtle.forward()
        xDif3 = xDif3 - xDif3
      else
        turtle.forward()
        xDif3 = xDif3 - xDif3
      end
    end
  end
end