Initially, the tag and insertion location is logged using a hand held computer or PDA, then it is inserted into the ore (eg a blast hole). The tag then travels with the aggregate through digging, transport and processing, before being sensed at detection locations (eg conveyor belts), when the time and specific tag is recorded. The RFID tag data is then loaded into a database and analysed as required.
The SmartTag system has five main components:
- A PDA, which enables the initial RFID tag insertion process to bee more efficient and accurate. Each RFID tag is added to the database with one of three options: a GPS co-ordinate, a pre-defined point (eg a blast hole) or a new point, which can be accurately located later. The system does not currently allow for high precision GPS but can locate the nearest point in a series of pre-defined points, such as blast holes, and allow the user to associate RFID tags with these points.
- The antenna, which is located at the conveyor belts. The antenna induces a charge on the tag and also receives a transmitted signal back from the tag. The antenna design is decided by its size and its robustness. The antenna?s size dictates the size and the strength of the field it radiates and is the largest available for this frequency of RFID system.
- An RFID reader, which decodes the signal from the antenna and determines the ID of the RFID tag passing the antenna. The reader then transmits the ID using serial communications.
- A data logging or buffer stage, which improves the reliability of the systems and makes movable systems possible. The data logger receives data directly from the RFID reader, stores the IDs with the time they were detected and monitors vital system parameters, such as the tuning state of the antenna. The data logging stage also makes SmartTag less reliant on communication links (eg wireless) as the data is stored at the detection point until a link is established to the software applications. The critical communications links, like the one between the antenna and the reader, are all wired and very reliable.
- The core of the SmartTag software is an SQL (Structured Query Language) database. The database, located on a dedicated server, stores all the information about the detection points, detected RFID tags and original locations.
The benefits of using SmartTag include linking spatial mine data to time based processing data, increased confidence in mineral blending, proactive process changes for known mineral types, and accurate measurement of residence times in stockpiles and bins.
Since 2007, Metso has made significant advancements with RFID technology that have enabled SmartTag to cover not just the secondary crushing process but tertiary crushing and beyond. This has been achieved by reducing the size of the SmartTags from a diameter of 60mm to 20mm. The new smaller RFID tags have been successfully used in several studies.
Source: Metso Process and Technology Innovation