been foreshortened by omitting the central portion thereof fully erected scaffolding 18 is shown in the drawings with a stair unit 20 extending upwardly from the level at which the sloping bottom walls 22 of boiler 12 meet the vertical sidewalls 24 in this example the access manhole 26 is positioned at the same level twenty feet below this level in the illustrated embodiment are throat truss beams 28 these trusses 28 are preferably planked over soon after having been put in place during the initial erection of the scaffolding 18 prior to putting the remainder of the scaffolding 18 in place so as to protect workmen cleaning out the ash pit not shown directly below the throat 16 as a result the throat 16 is not accessible during most of the scaffolding erection procedure although this throat may run the depth of the boiler e g on the order of 50 39 its width is typically 21 2 39 or less this is in contrast to the 3 39 width of the container 10 in its preferred embodiment were the throat even conveniently available at the time that the container is introduced into the boiler furthermore the ash pit itself is typically limited in space because of the presence of a discharge auger and its associated machinery and because typically there is only a 2 39 u00d7 4 39 access manhole to the ash pit a boiler 12 may often.