an exhaust outlet 118 of collection tank 14 by a hose 120 as shown in fig1 7 8 and 9 an exhaust side 122 of vacuum pump 28 connects to a silencer 124 such as a model ts30tr silencer manufactured by cowl the output of silencer 124 exits into the atmosphere the vacuum air stream pulled through vacuum pump 28 produces a vacuum in collection tank 14 that draws a vacuum air stream through collection tank inlet 90 when inlet 90 is not closed off by a plug 127 fig1 the inlet may be connected to hose 88 leading to digging tool 32 thus the vacuum air stream at inlet 90 is ultimately pulled through vacuum passage 86 at distal end 94 of tool 32 because it is undesirable to draw dirt or other particulate matter through the vacuum pump a baffle system for example as described in u s pat no 6 470 605 the entire disclosure which is incorporated herein is provided within collection tank 14 to separate the slurry mixture from the vacuum air stream consequently dirt rocks and other debris in the air flow hit a baffle not shown and fall to the bottom portion of the collection tank the vacuum air stream after contacting the baffle continues upwardly and exits through outlet 118 through filter 116 and on to vacuum pump 28 referring once again to fig1 collection tank 14 includes a discharge door 126 connected to the main tank body by a hinge 128 that allows the door to swing open thereby providing access to the tank 39 s interior for cleaning a pair of hydraulic cylinders 130 only one.