Single Shaft Miner

-- variables
height = 0
distFront = 0
distRight = 0
curDepth = 0

-- Functions

local function tMove(distance)
  for i=1,distance do
    while turtle.forward() == false do
      turtle.dig()
      turtle.attack()
      sleep(0.5)
    end
  end
end

local function tDescend(distance)
  for i=1,distance do
    while turtle.down() == false do
      turtle.digDown()
      turtle.attackDown()
      sleep(0.5)
    end
  end
end

local function tAscend(distance)
  for i=1,distance do
    while turtle.up() == false do
      turtle.digUp()
      turtle.attackUp()
      sleep(0.5)
    end
  end
end

local function turnaround()
  turtle.turnRight()
  turtle.turnRight()
end

local function checkInv()
if turtle.getItemCount(16) > 0 do
  tAscend(curDepth)
  turtle.turnLeft()
  tMove(distRight)
  turtle.turnLeft()
  tMove(distFront)
  for i=1,16 do
    turtle.select(i)
    turtle.drop()
  end
turtle.set(1)
  turnaround()
  tMove(distFront)
  turtle.turnRight()
  tMove(distRight)
  turtle.turnLeft()
  tDescend(curDepth)
end
end

-- Startup

term.clear()
term.setCursorPos(1,1)
print("Ready to mine shafts!")
print()
print()
print("Choose forward offset:")
distFront = read(input)
print("Choose right offset:")
distRight = read(input)
print("Choose depth:")
depth = read(input)

--Main Loop
tMove(distFront)
turtle.turnRight()
tMove(distRight)
turtle.turnLeft()
for i=0,depth do
  checkInv()
  tDescend(1)
  curDepth = curDepth + 1
end
tAscend(depth)
turtle.turnLeft()
tMove(distRight)
turtle.turnLeft()
tMove(distFront)
for i=1,16 do
  turtle.set(i)
  turtle.drop()
end
turtle.select(1)
turnaround()