Mine

-- TODOS:
-- implementation of sand and gravel handling

-- digging a 3x3 area with a length of n blocks
print("how far?")
Length = tonumber(read())

while turtle.getFuelLevel() < Length * 5 do
    print("not enough fuel")
    sleep(2)
    Fuel()
end


-- checking if the turtle has a chest in the last slot
turtle.select(16)
while true do
    if turtle.getItemDetail() then
        local item = turtle.getItemDetail()

        while item.name ~= "minecraft:chest" do
            print("vanilla chest needed in last slot!")
            sleep(5)
        end

        break
    else
        print("vanilla chest needed in last slot!")
        sleep(5)
    end
end


-- checking if the turtle has enough torches in the second to last slot
turtle.select(15)
while true do
    if turtle.getItemDetail() then
        local item = turtle.getItemDetail()

        while item.name ~= "minecraft:torch" do
            print("vanilla torches needed in second to last slot!")
            sleep(5)
        end

        if turtle.getItemCount() then
            local itemCount = turtle.getItemCount()
            local minTorches = Length / distanceTorches

            while itemCount < minTorches do
                print("not enough vanilla torches!")
                sleep(5)
            end
        end

        break
    else
        print("vanilla torches needed in second to last slot!")
        sleep(5)
    end
end


-- 3x3 area per block
for i = 1, Length, 1 do
    turtle.digUp()
    turtle.digDown()
    turtle.turnLeft()
    turtle.dig()
    turtle.forward()
    turtle.digUp()
    turtle.digDown()
    turtle.turnRight()
    turtle.turnRight()
    turtle.forward()

    -- place a torch every 3rd block
    if i % distanceTorches == 0 then
        turtle.turnLeft()
        turtle.turnLeft()
        turtle.select(15)
        turtle.place()
        turtle.turnRight()
        turtle.turnRight()
    end

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


    if Length > i then
        turtle.dig()
        turtle.forward()
    end
end


-- chest must be placed in 16th slot
turtle.select(16)
turtle.placeDown()


for i = 1, 16, 1 do
    turtle.select(i)
    turtle.dropDown()
end