Pulsed electron spin resonance (ESR) experiments are presented to study hole burning in the ESR spectrum of p-type Si:B. The results are used to determine the electron spin-lattice relaxation process and to prove that spectral diffusion is absent. It follows that dynamic nuclear polarisation of 29Si nuclei in this substance arises from the 'solid effect'. Additional holes due to the transitions, where electron and nuclear spins flip simultaneously, are also observed. A study of these additional holes yields the probability of this latter type of transition.