Maintaining a metallurgical accounting system in a functional state, in addition to performing routine metal balances, demands a significant commitment of time and effort from site metallurgists. Additionally the discrepancy between indicated and reconciled gold production for a given month will often result in time consuming debate and investigation that is based on prevailing expectations around acceptable discrepancy limits within the site or company.
In order to avoid unwarranted and potentially unproductive investigations into perceived accounting discrepancies that may well be nothing more than natural variations within a given system, it is necessary to ensure some rigour is applied to establish the discrepancy limits that define system performance. In so doing one can ensure that an operations technical resources can focus on optimisation of the business.
Through the diversity of its metal recovery operations Newmont has collected a detailed database of metallurgical accounting discrepancy data over several years of operation. The operations range from low to high levels of compliance with best practice metallurgical accounting standards. The Newmont data shows that the level of compliance with best practice is not always consistent with the greatest metallurgical accountability.
The plant operator, and site management, must be cognisant of the value generated through improvements to the metal accounting process given the often considerable expense and ongoing effort that can be required to support these changes. Change should only be made where value, either direct or indirect, can be added.
A, Dunne, R and McCaffery, K, 2012. Defining practical metallurgical accounting
discrepancy limits for gold operations, in Proceedings 11th AusIMM Mill
Operators’ Conference , pp 3-10 (The Australasian Institute of Mining and Metallurgy: Melbourne).