mine

function fuel()
  if turtle.getFuelLevel() <= 60 then
    turtle.select(16)
    turtle.refuel()
  end
end

local depth = 0

function isValuable()
  local n = {"minecraft:stone", "minecraft:dirt", "minecraft:gravel", "minecraft:cobble"}
  local success, whatIt = turtle.inspect()
  local whatIsThis = whatIt.name


  for key,value in ipairs(n) do
    if whatIsThis ~= value then
      return true
    else
      return false
    end
  end
end


--[[
turtle.digDown()

while turtle.detectDown() == false do
  fuel()
  turtle.down()
  if isValuable() then

  turtle.digDown()
end
]]--

if isValuable() then
  turtle.dig()
end