ChemLab is overhaul mod despite being addon to BuildCraft and it adds very intrusive worldgen and additional mechanic to vanilla. Those aspects are configurable. If you need more configuration options contact me for suggestions.

Resides in chemlab.cfg

Currently ChemLab allows you to disable iron processing injection by setting T-L0:WROUGHTIRON to

By default ChemLab generates vast limestone areas with big chunks of ore - just for your quarries, but if you don't like it and want some vanilla feeling you can enable equally scattered mode:

If you wish to turn some dims into mining worlds feel free to do so. It is now possible with allowedDims config option. For example if I want CL to generate in overworld, twilight forest and deep dark(if their dim ids are default):

  I:allowedDims <
      0
      7
      -100
   >

There is Gas Chimney Machine. It has particles and on some slow hardware they can lag a bit. You can disable them at all:

or disable particle injection per frame:

Resides in hoelib.cfg

There is a possibility of enabling HOE KeepAlive mechanism, but IT IS NOT RECOMENDED(NOT YET FINISHED. IT WILL BREAK WORLDS). Really, don't touch

This configuration allow server owners to tune how HOEThread will return to OS for changing affinity and relieving CPU load.

By default it is RETROPREDICTIVE which assumes it will wait the same time it wasted for cycling one execution before. It is good for small servers or SSP, because small amount of working HOE Machines don't press CPU at all. After some time you may start noticing small stuterring in machines behaviour. It is because it relieves server from load at variable times which is performance efficient but not so smooth. You may consider switching to STEPPING in which case it will wait every 10 msec before it reaches 5 steps to execute HOE Machines. PERCYCLE - is the most smooth option available, but it expects some precision and low load from OS, otherwise it may stutter hard. It is recommended for big CL-centered servers. NONE disables retention at all. It may prove useful on NUMA-based hardware.

There is option planned to switch between DISCRETE execution(like minecraft does by default, per tick update) or to use CONTINUOUS execution which will make machines bend their timing to get the maximum performance possible from your hardware.