In suryevor right-click the industry. Somewhere in the window that you can set ____ consumed per minute, depending on the industry.
The Auran Coal Mine, with the diesal unload track, for example, can have different rates of diesal consumption and coal production, depending on your demands.
You might also want to look into the LARS comodity system put out by trainzproroutes.org It really is a fun little system.