The configuration of the subscale combustor has evolved during the six years of this program from a system using only an impact separator to remove particulates to a system which also included a slagging cyclone separator before the lean-quench combustor. The system also now includes active slag tapping after the impact separator rather than a bucket to collect the slag. The subscale 12 MM Btu/hr (higher heating value, HHV) slagging combustor has demonstrated excellent coal-fired operation at 6 atm. The combustor has fired both coal-water mixtures (CWM) and pulverized coal (PC). Three Wyoming subbituminous coals and two bituminous coals have been successfully fired in the TVC. As a result of this active testing, the following conclusions may be drawn: (1) it was possible to achieve the full design thermal capacity of 12 MM Btu/hr with the subscale slagging combustor, while burning 100% pulverized coal and operating at the design pressure of 6 atm; (2) because of the separate-chamber, rich-lean design of the subscale slagging combustor, NO{sub x} emissions that easily meet the New Source Performance Standards (NSPS) limits were achieved; (3) carbon burnout efficiency was in excess of 99% when 100% coal-fired; (4) ninety percent of the ash can be separated as slag in the impact separator, and a total 98 to 99% removed with the addition of the slagging cyclone separator; (5) Objectives for third-stage exit temperature (1850{degrees}F), and exit temperature pattern factor (14%) were readily achieved; (6) overall pressure loss is currently an acceptable 5 to 6% without cyclone separator and 7 to 9% with the cyclone; and (7) feeding pulverized coal or sorbent into the combustor against 6 atm pressure is achievable.