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.