A portable truck dump comprises a conveyor system mounted on an elongate frame to transport material from a first end of the frame to a second, opposite end of the frame. The controller determines a first arrival time for a first machine to arrive at the boundary and a second arrival time for a second machine to arrive at the boundary. comprising the steps of connecting in tandem a multiple stack of power semiconductor SCR thyristor circuit switching sections. The porogen is decomposed to form pores within the matrix material, and a reactive gas phase species is patternwise directed onto a surface of the matrix material. and under a pressure of at least about 100 bars so that any gases generated in the first stage are converted into C1-C4 alcohols with the weight ratio of C1-C2 to C3-C4 between about 0-35% to 100-65%.