It would be a shame to burn Bitum in that nice stove... The bitum will make the glass opaque within about ten minutes of burning... I'd lean more towards a Harman Mark II or Mark III. The Mark models have secondary air vents on the loading door, and this should help burn up the volitiles off of the Bitum coal.
Since you get your coal at work, can you use a pitch fork like I mentioned and sift out some coal from the fines before it all goes through the grinder?? If you can get the coal pieces, from say ripe olive size up to large chicken egg size, you will like the way it burns.. more surface area and more heat.
To burn bitum well, you need to add pre-heated oxygen-rich air over the fire for the first hour or so after fresh coal is added. During this first hour, the volitiles burn off the coal, and need lots of hot oxygen to fully burn. The soot from a bitum coal fire is incomplete combustion of the volitiles. Once the voltiles have burn off, the coal burns almost identical to anthracite. Some bridging, and more ash, but with clean blue flames usually.
The underfeed stoker I have in my 'Big Bertha' is designed to burn bituminous coal, As the coal is pushed up into the hot retort, under the fire, the coal is heated, the volitiles go up through the burning coal bed, get burnt completely, so the soot is minimal, then the coal continues to rise into the burning area, and burn fully.
I'd keep an eye on your local papers, craigslist.com and bulitin boards, I'd even post 'want to buy' ads for coal stoves, you never know what may show up.