Alex Campbell

Rio Tinto | RIOTINTO

Numerous studies have proved that blast design impacts gravity flow in sublevel cave mines. However, such designs are yet to be fully optimised owing to the small number of mines with published full-scale experimental studies specifically planned to measure the effect of blast design variables on fragmentation and recovery. This paper details the r...

A major disadvantage of the sublevel cave (SLC) mining method is the potential for substantial dilution and ore loss. Scale model experiments demonstrate that gravity flow and recovery in SLC mines is affected by cross-cut geometry. Several authors also suggest that cross-cut height affects the digging depth of loading equipment and therefore influ...

Many caving mines use numerical fl ow models to simulate mine production, forecast recovered ore grades and optimise the draw strategy. In sublevel caving (SLC) mines, the effects of blasting and fragmentation at an individual ring scale generally cannot be included in these models. Previous attempts to use results from marker recovery trials to ca...

The particle size distribution of fragmented rock in mines affects operational performance of loading equipment, materials handling and crushing systems and is known to influence ore flow in caving mines. A number of methods to measure rock fragmentation exist at present, however these systems have a number of shortcomings in an underground environ...

The particle size distribution of fragmented rock in mines significantly affects operational performance of loading equipment, materials handling and crushing systems. A number of methods to measure rock fragmentation exist at present, however these systems have a number of shortcomings in an underground environment. This paper outlines the first i...

The objective of the draw strategy in a caving mine is to maximise economic return by minimising waste dilution1 and maximising ore recovery2. The draw strategy must also include suitable controls for air blast and mud rush hazards and is highly constrained until continuous cave propagation has been achieved. This paper details a three year project...

The Ernest Henry mine is a transverse sublevel cave (SLC), which is relatively unique due to the 45 degree inclination of the orebody. To economically recover ore, each sublevel is horizontally offset from the previous level by around 25 m, depending on the orebody geometry. Mine development, slotting and initial production within this zone occurs...

Cave propagation is a complex process due to interacting variables including mine geometry, rock mass heterogeneity and complex structural networks and stress fields. The Ernest Henry sub-level cave (SLC) is directly below an open pit which provided an opportunity to observe and measure rock mass failure as the cave initiated and propagated through...

The increasing availability of marker data in sublevel caving operations is changing the way draw can be managed to achieve positive recovery outcomes in these mines. This paper describes how marker data has been incorporated into flow simulations to help calibrate full mine simulations for the forecasting and optimisation of recovery. Some flow m...

Underground mines commonly use ore pass systems as a safe and economic method to transport broken rock between levels. Although these systems are an integral part of such operations, design methodologies are generally limited to empirical methods, rules of thumb and limited case studies. This paper details ore pass design issues in an operating sub...

Situated in north-west Queensland, Australia, the Ernest Henry Mine (EHM) has been producing copper and gold since 1996. Owned and operated by Glencore Xstrata, ore is currently sourced from a newly developed underground sublevel cave (SLC) mine below the old EHM open pit (the pit). Ore feed to the concentrator is supplemented by satellite open pit...

The Ernest Henry crusher chamber is a large excavation located at a depth of approximately 1 km. During the pre-feasibility study, a single exploration drill hole was extended below the orebody which identified no adverse ground conditions and the crusher location was set. Additional diamond drilling into the planned crusher chamber location was co...

Cannington Mine has been developing through paste backfilled stopes since the year 2000. These paste drives have been used as either production drill accesses or long-term bypasses. Prior to this study, the ground support requirements for each paste development cut were: an initial 50 mm layer of fibrecrete, weld mesh bolted with 2.4 m split sets,...

Open pit blasting at Ernest Henry Mining has the potential to cause damage to nearby underground workings. This paper is a case study of the blast vibration management project that was conducted to ensure open pit blasting did not adversely affect the stability of upper production levels or cause damage to the underground primary fan units. The two...