BetterTunnel.lua

--function declarations
function fuelTurtle(needed)
    turtle.select(1)
    --Check if first slot has fuel
    if not turtle.refuel(0) then
        print("Waiting for Fuel in slot 1")
        --Wait for fuel
        while not turtle.refuel(0) do
            sleep(1)
        end
    end

    --refuel until good
    while needed >= turtle.getFuelLevel() do
        turtle.refuel(1)
    end
end --End of Fuel Turtle

function digFront()
    while turtle.detect() do
        turtle.dig()
        sleep(0.5)
    end
end

function digUp()
    while turtle.detectUp() do
        turtle.digUp()
        sleep(0.5)
    end
end

--main
--Get input
local distance, width, height = ...

print("I shall commence mining")

--Turn input to numbers
distance = tonumber(distance)
width = tonumber(width)
height = tonumber(height)

--If the turtle is facing right currently
rightFacing = true

--Repeats for distances down lane
for x = distance, 1, -1 do
    --Check for fuel
    local fuelNeeded = width * height

    if fuelNeeded >= turtle.getFuelLevel() then
        fuelTurtle(fuelNeeded + width)
    end

    local heightLeft = height - 1

    --Commit mining
    --Dig block in front
    digFront()
    turtle.forward()

    if rightFacing then
        turtle.turnRight()
    else
        turtle.turnLeft()
    end


    heightLeft = height
    --Goes along height
    while heightLeft > 0 do
        --Goes along width
        for move = width - 1, 1, -1 do
            --Mines block in front, and top if appropiate and move forward
            if heightLeft > 1 then
                digUp()
            end
            digFront()
            turtle.forward()
        end

        if heightLeft > 1 then
            digUp()
        end

        --Set to mined height
        heightLeft = heightLeft - 2

        --Checks if there is height left, then go up there
        if heightLeft >= 1 then
            turtle.up()
            digUp()
            turtle.up()
        end
        turtle.turnRight()
        turtle.turnRight()

        rightFacing = not rightFacing
    end

    --Face Wall
    if rightFacing then
        turtle.turnLeft()
    else
        turtle.turnRight()
    end

    for h = height - 1, 1, -1 do
        turtle.down()
    end
end
print("Done!")