bund - это барьер (насыпь или вал) для предотвращения доступа к опасному участку, см., например, рис. 2 и текст в руководстве по ТБ в шахтах https://www.dnrm.qld.gov.au/__data/assets/pdf_file/0019/2403...
rolling bund - это передвижной защитный барьер (металлический)
Цитата из отчета по расследованию гибели оператора ПДМ на шахте, стр. 8
http://www.coronerscourt.wa.gov.au/_files/Ross_finding_2014....
37. At the 1A ore body, backfilling of stopes was generally done with loaders from the top levels. When backfilling of a stope was carried out, procedures required the use of a steel ‘bund’ or ‘wheel stop’ to be fixed at the top level at minimum of 1.5 metres from the edge. The steel bunds were bolted to the drive walls with chains. The use of bollards and signs was required, and flood lights were required to be used at six metres and 10 metres from the tipping points.