All experimental data for proton-nucleus collisions at ultrarelativistic energies confirms the "Anomalous nuclear enhancement" phenomena, which gives a cross section dependence upon the atomic number A as oPA = oppA^a with a greater than 1. This power law dependence cannot be explained by QCD parton-models if only a single proton-nucleon hard collision is assumed, for then a power of 1 would emerge. The effect of multiple-hard scattering of partons inside the nucleus is studied in this thesis. E^T cross sections and other variables, such as planarity and multiplicity, are studied within the multiple scattering model using Monte Carlo techniques. The results are compared with data for two different un-biased triggers, the global trigger and the two-high trigger. Judgments on the importance of multiple scattering are made.