Detection of ore and waste border is becoming ever more important in large underground metal mines. One solution that a Finnish company IMA Engineering has been testing and developing is ore scanning in loader bucket during normal production.

In this application on-line analytical equipment scans buckets full of material in loading and when cut-off point is reached loading is either stopped or material is moved to in-fill location. IMA has developed and tested various technologies including XRF and laser based methods (such as LIBS and LIF) and now such Bucket Scanner systems are available.

Based on the test work done so far and due to the nature of this application some modifications are needed in the mining process, thus testing and development project at site is often required. IMA offers now a test and research unit for such test and research work. Each test device is modified to match the specific conditions of each mine and calibrated to measure desired elements. Basically such test unit is installed on a movable special rack system, which can be temporarily installed and taken in use both in underground and in open pit mines or in material storage areas.

The LHD driver brings selected material in the bucket under the Scanner Probe, the Bucket Scanner measures the material in the LHD Bucket in few seconds and the LHD loader moves the material to the desired destination based on the analysis result .Ore grade data is immediately available after the measurement: data of ore elements and their grades can be shown e.g. on a traffic light system. Data can be transferred electrically also to the mine planner and geologist.

Bucket Scanner will be installed in a safe measuring location taking in to consideration the operator health and safety and protection of the equipment from mechanical damage. In case of X-Ray system both power and high voltage are kept low. Lasers, being Class 4 equipment, are also used inside shield enclosure.

XRF method has been tested successfully with good performance in metal mine applications with e.g. the following elements: iron, copper, zinc, arsenic, lead, etc. Measuring accuracy is proven to be good enough to detect ore and waste at cut-off levels. Bucket surface and grain size variation have taken into account in calibration. The accuracy of the calibration is monitored with verification sampling and the samples will be measured in laboratory.