The past number of years has seen a sharp rise in the gold price. This has led to renewed activity in the gold sector and especially in refractory ore-bodies that are not economically feasible at lower gold prices. There have, historically, been a total of eleven BIOX® plants commissioned world wide with eight currently in operation. The most recent plants to be commissioned were Bogoso and Jinfeng in 2007 and Kokpatas in Uzbekistan in 2008. Design of the Bogoso BIOX® plant was started by Minproc in 2005. The design throughput of the sulphide BIOX® circuit is 820 tpd concentrate at a feed sulphide sulphur grade of 20 %. The Bogoso BIOX® plant has the largest biooxidation reactors with a live capacity of 1,500 m3 each. Plant design on the Jinfeng project started in 2005 and the engineering was performed jointly by Ausenco and Nerin. The BIOX® plant has a design capacity of 790 tpd concentrate at 9.4 % sulphide sulphur. The Kokpatas plant will be the largest BIOX® plant in the world with a Phase 1 design concentrate treatment capacity of 1,069 tpd at 20 % sulphide sulphur. The throughput will be doubled during Phase 2. Interestingly, unlike other BIOX® Plant, this plant will use a resin-in-pulp circuit for gold recovery, but the design will allow the plant to be converted to Carbon-in-pulp if required. There are currently three BIOX® projects in various stages of design or construction. This includes two expansions to existing BIOX® operations and one new BIOX® project. There are a number of major R&D projects currently under investigation with some very positive results. Most R&D is focussed on the main capital and operating cost items in the process, but there are also projects focussed purely on process optimisation and improvement.