Face to Surface : a fragmentation study

• Main Authors: Gustafson, Anna, Johansson, Daniel, Schunnesson, Håkan
• Format: Report
• Language: English
• Published: Luleå tekniska universitet, Geoteknologi 2016
• Subjects: Other Civil Engineering; Annan samhällsbyggnadsteknik; Luossavaara; Malmberget; giron
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-23034

As ore grades have decreased and the mining depth has increased over the past few decades, other characteristics than ore grade and tonnage are becoming important. The underground mining process, from in-situ rock mass characteristics to the final mill product with fully liberated minerals, consists of a chain of unit operations that impact, and are influenced by, fragmentation. This report presents the baseline mapping of the project “From Face to Surface”, studying the effects of fragmentation on the process flow in an underground SLC mine. It analyses the underground unit operations in detail, from mine planning to shafts, and maps the blast fragmentation’s effect on the process flow. The goal is to provide a deeper understanding of fragmentation´s effect on different unit operations. The objective is to describe the mining operation at Luossavaara-Kiirunavaara AB (LKAB) and identify key areas for improving fragmentation. To understand how fragmentation influences different operations in the mine, the project conducted a literature study, collected data and interviewed mine personnel in LKAB’s Malmberget mine. Data were collected from the mine’s internal systems, such as GIRON, WOLIS, IP21 and a local drilling data system. The interviews were conducted in cooperation with research personnel from the mine.This baseline mapping shows that the mining operation in Malmberget is affected by fragmentation in several ways. For some unit operations, the fragmentation has a large impact, while for others, it has none at all. The influence of fragmentation starts with the loading operation after the initial blasting and ends with the crushing operation. For the former, boulders are the largest problem, as they cause a great deal of idle time, either when they have to be moved to a separate drift for secondary blasting or when they create hang-ups in the ore passes. When boulders are dumped into the ore passes, they risk damaging the ore pass walls. If boulders create a hang-up, it has to be removed. If the hang-up must ...