Looking for Accurate Forecasting of Copper TC/RC Benchmark Levels

Abstract

Forecasting copper prices has been the objective of numerous investigations. However, there is a lack of research about the price at which mines sell copper concentrate to smelters. The market reality is more complex since smelters obtain the copper that they sell from the concentrate that mines produce by processing the ore which they have extracted. It therefore becomes necessary to thoroughly analyse the price at which smelters buy the concentrates from the mines, besides the price at which they sell the copper. In practice, this cost is set by applying discounts to the price of cathodic copper, the most relevant being those corresponding to the smelters’ benefit margin (Treatment Charges-TC and Refining Charges-RC). These discounts are agreed upon annually in the markets and their correct forecasting will enable making more adequate models to estimate the price of copper concentrates, which would help smelters to duly forecast their benefit margin. Hence, the aim of this paper is to provide an effective tool to forecast copper TC/RC annual benchmark levels. With the annual benchmark data from 2004 to 2017 agreed upon during the LME Copper Week, a three-model comparison is made by contrasting different measures of error. The results obtained indicate that the LES (Linear Exponential Smoothing) model is the one that has the best predictive capacity to explain the evolution of TC/RC in both the long and the short term. This suggests a certain dependency on the previous levels of TC/RC, as well as the potential existence of cyclical patterns in them. This model thus allows us to make a more precise estimation of copper TC/RC levels, which makes it useful for smelters and mining companies.