*This is an abstract only. No full paper is available for this abstract.* In the 20th century, reconciliation activities were largely ad hoc and very dependent on either: the skills and interest of mine staff short investigations of disagreements between forecasts and production that were generally discontinued as soon as things became 'right'._x000D_
From the 1990s there was increasing recognition that reconciliation activities had to be continuous and formed an important and systemic component of corporate governance. Far-sighted staff and company executives realised that reconciliation provided the only serious view on orebody performance. This led to looking for reasons for changes in resource and reserves position, illustrated by waterfall plots. In addition, some of the worst problems plaguing the past were solved or improved in the areas of production control and accounting via grade control systems, global positioning system (GPS) guided equipment and dispatch monitoring of trucks from the face to the crusher._x000D_
Increasingly reconciliation issues are now found related to lack of orebody knowledge in terms of location of the geometric limits of ore, and inadequate understanding of the irregularities of contacts and the ability of mining to follow them. The best person to deal with these issues is the mine geologist and it is essential that the reconciliation systems maintain and increase visibility of insightful interpretation of risks and opportunities._x000D_
Once the location and irregularities of the contacts are understood, it remains to determine whether the value of additional information is merely an insurance policy or a springboard to more selective mining methods that can be successful with guidance from the mine geologist._x000D_
CITATION: Parker, H M, 2014. The evolution of 21st century reconciliation systems - why geologists and geology will be at the core of these developments in the future, in Proceedings Ninth International Mining Geology Conference 2014, pp 43-44 (The Australasian Institute of Mining and Metallurgy: Melbourne).