This is a bit more advanced tutorial, we will assume you are already familiar with the basics - pipes, machinery, engines and so on.
Infinite storageEditThis is quite useful if you need a lot of some resource, but don't want to have dozens of chests holding everything you need. The logic is simple - the iron pipe accepts the items incoming from its back and forwards them towards the chest. The pipe next to the chest has a 50% chance of sending the item to the chest or sending it back to the iron pipe. Once the chest is full, the items will just traverse trough the loop created, thus saving a lot of space otherwise used for chest to store the resources. This combination is best used with quarries and diamond pipes, if you need a lot of cobblestone,sand or something else. Note that a lot of blocks in loops will cause a notable fps drop (eg all the cobblestone from a 15x15 quarry)
Combustion engines without coolingEditIf you have machinery with local power source, which is not required to have continuous operation, you can use a combustion engine operated by a gate. Setting the gate to condition "Engine safe" and action "Redstone signal" will keep the engine operating on around 65% capacity - it will work around 7 minutes, then stop and cool down back to 0°C in approximately 4 minutes. This will give you rate about 4500 MJ/min if the engine is running on fuel. This is suitable for a portable quarry, a set of lasers, which produce non-urgent items, a compact refinery and so on. This design is extremely space economic, as it eliminates the need for a pump, waterproof pipes, power loss for powering the pump.
The world of Minecraft is divided in so called "chunks" - 16x16 areas of blocks, which are loaded or unloaded depending on game settings, server side settings, players' positions and machinery placed. In Buildcraft, the only machine affecting the chunk loading, is the quarry, which keeps all the chunks intended for mining, in the memory. Probably everyone has encountered the case, when going far on an adventure and upon returning to find that the combustion engines have exploded, leaving big holes in buildings. This occurs because of chunks with pumps and engines have been unloaded from memory. Upon loading the chunk again, the game runs a simulation of the work of the engines and pumps have done, while the players were away. Since the simulations are run separately for every object, this effectively ignores the work of the pumps, resulting in overheating and explosion of the engines.This can be avoided by using a so called "chunk loader" - a separate object, like the loader by chicken_bones or by using an underground quarry. The area which needs to be always loaded (typically the engines and their pumps) is defined by landmarks deep underground so the quarry is out of the way. There is no need of powering the machine, simply placing it does the work. Using a quarry can be a costly, since the need of diamonds and gold to craft it.