Mining v 2.1

near=true
blocksTravelled = 0

function detectLava()
    turtle.up()
    for i=0, 2, 1 do
        if not turtle.detectUp() then
            if turtle.digUp() then
                turtle.placeUp()
            end
        end
        turtle.turnLeft()
        if not turtle.detect() then
            if turtle.dig() then
                turtle.place()
            end
        end
        turtle.turnRight()
        turtle.turnRight()
        if not turtle.detect() then
            if turtle.dig() then
                turtle.place()
            end
        end
        if i == 0 then
            turtle.down()
        end
    end
end

function mine(num)
    for i=0, num, 1 do
        while turtle.detectUp() do
            turtle.digUp()
        end
        while turtle.detect() do
            turtle.dig()
        end
        while not turtle.forward() do
            turtle.dig()
        end
        detectLava()
    end
end

function checkInventory()
    if turtle.getItemCount(8) > 0 then
        dropOff()
    end
end

function dropOff()
    turtle.turnRight()
    turtle.turnRight()
    for i=0, (blocksTravelled - 1), 1 do
        turtle.forward()
    end
    if not near then
        turtle.turnLeft()
        for i=0, 16, 1 do
            turtle.forward()
        end
        turtle.turnRight()
    end
    sleep(10)
    turtle.turnRight()
    turtle.turnRight()
    if not near then
        turtle.turnLeft()
        for i=0, 16, 1 do
            turtle.forward()
        end
        turtle.turnRight()
    end
    for i=0, blocksTravelled - 1, 1 do
        turtle.forward()
    end
end

function segment(mirror)
    turn = function() error("Turn not being assigned") end
    reverseTurn = function() error("ReverseTurn not being assigned") end
    if mirror == true then
        turn = turtle.turnRight
        reverseTurn = turtle.turnLeft
    else
        turn = turtle.turnLeft
        reverseTurn = turtle.turnRight
    end
    turn()
    mine(16)
    near = not near
    turn()
    mine(2)
    reverseTurn()
    reverseTurn()
    mine(5)
    blocksTravelled = blocksTravelled + 3
    checkInventory()
end

for i=0, 10, 1 do
    segment(false)
    segment(true)
end