Gravelator

--[[

I wrote this to test items coming from a vacuum hopper, if they fuzzy match the naming criterion, then
it assumes they are are broken ores, and then crafts as many as it can into a 2x2 grid, making gravel ore

It keeps up well on a simple system with four sieves and 4 activators per sieve, might be able to handle
larger volumes.

In my build I had 4 sieves surrounding an Iron chest, a vacuum hopper was placed on top of this chest
The crafty turtle was below it, and a chest was below the turtle, the top 10 lines or so should be all
you'd need to change to make it cater to your build

]]
-- Broken Ores come from this chest
local chest = peripheral.wrap("top")
-- The turtle's direction in relation to chest.
local turtleDir = "down"

function dropItems()
  -- rewrite this to drop slot 1 wherever
  turtle.select(1)
  turtle.dropDown()
end

--[[ Leave the rest alone, or break it.. or whatever.. ]]

function isBrokenOre(stack)
  if stack == nil then
    return false
  end

  local bstart,bend = stack.name:find("Broken")
  local ostart,oend = stack.name:find("Ore")

  if bstart == nil then
    return false
  end

  if ostart == nil then
    return false
  end

  return true
end

function fetchSlot(slot, qty)
  chest.pushItem(turtleDir, slot, qty)
end

function makeGravel(slot, stack)
  local c = math.floor(stack.qty/4)
  local qty = c * 4

  fetchSlot(slot, qty)
  turtle.transferTo(2, c)
  turtle.transferTo(5, c)
  turtle.transferTo(6, c)

  turtle.craft()
  dropItems()
end

function scanChest()
  chest.condenseItems()
  local stacks = chest.getAllStacks()

  for i,stack in ipairs(stacks) do
    if isBrokenOre(stack) then
      print("ORE: ", stack.name, "  ", stack.id)
      if stack.qty >= 4 then
        makeGravel(i, stack)
      end
    else
      -- transfer through
      chest.pushItem(turtleDir, i, stack.qty)
      dropItems()
      print("     ", stack.name, "  ", stack.id)
    end
  end
end

while true do
  scanChest()
end