form a slurry at hopper 31 hopper 31 is also well known and completely described in u s pat no 3 931 936 entitled 34 apparatus for crushing solids in a liquid medium 34 by eston f petry and ronald w umphrey once mining has progressed past the point where the haulage system can extend it will be disconnected from the terminations 26 and 27 of pipes 22 and 23 and connected to pipes 22a 23a at their terminous 26a and 27a as is illustrated in fig1 additional pipes 22b and 23b which have previously been laid will be utilized once the slurry haulage system has progressed to the point where it is fully extended once the slurry haulage system 25 is disconnected from the terminations 26 and 27 of pipes 22 and 23 extensions 40 and 41 are added to pipes 22 and 23 respectively to the edge of the mined out section 17 thus pipe extensions 40 and 41 would terminate at locations 42 and 43 respectively the surrounding area around and over the pipes can be filled in with overburden as is illustrated in the previous strip 13 continued mining such as strip 18 will result in added sections or extensions 44 and 45 to pipes 40 and 41 respectively as the extensions are added it becomes necessary to boost the pressure in the pipes to accomplish this a boosting station generally referred to by.