Throughout the years the mining company Boliden Mineral AB have had difficulties producing a working fine filter for their tailing pond at the Aitik copper mine. The problem with the fine filter occurs when it gets placed on the tailing pond wall. Coarse grains break down into fine grains and the entire composition of the fine filter is changed. The material that is used to produce the fine filter comes from the mine’s own waste rock supply. The primary waste rock in Aitik comprises of heterogeneous gneiss and pegmatite. To determine why the waste rock isn’t holding together well enough the mechanical strength of the rock is investigated. Huge differences for the mechanical strength both exist between the different rock types, but also in the different kinds of the gneiss. The effect of the explosions, used to mine the ore, and the crushing machine also impacts on the mechanical strength of the rock. Good mechanical strength is found in rock that has a high amount of secondary transformation like epidote and bad mechanical strength from foliated rock. To get the best mechanical properties it is suggested to exploit epidote transformed rock found in deformation zones, adjacent to the ore deposit or the pegmatite intrusions. It is also recommended to use less powerful charge when blasting rock material that will be used for production of the fine filter.

Boliden Mineral AB är ett metallföretag som producerar metaller för det moderna samhället. Företaget har två dagbrottsgruvor belägna i Aitik strax utanför Gällivare i norra Sverige, varav en är landets största dagbrott. Stora gruvtruckar av två olika modeller transporterar malm från gruvan till anrikningsverket där koppar och andra metaller utvinns. Truckarna utgör en viktig del av logistiken som influerar den totala produktiviteten i verksamheten. Skadade truckdäck har visat sig vara en av de största orsakerna till tillgänglighetsförluster för truckarna. Studiens syfte var att skapa en nulägesbeskrivning gällande underhållskedjan av skadade truckdäck i företaget samt ge förslag på förändringar av däckunderhållet för att förbättra tillgängligheten på truckarna genom att minska nedtiden för däckskador. Intervjuer med inblandade personalgrupper i underhållskedjan samt analyser av underhållsdata ligger till grund för resultatet i studien. En RAMS-analys utfördes för att finna felorsaker i underhållskedjan som bidrar till lägre driftsäkerhet av gruvtruckarna med avseende på däckskador. RAMS-analysen påvisade att de flesta flaskhalsarna i underhållskedjan finns inom området underhållssäkerhet, vilket innebär att underhållsorganisationen reagerar för långsamt för att underhållet ska kunna bedrivas optimalt. Däckunderhållet tar generellt för lång tid i förhållande till de ideala feltider som vore möjliga att uppnå för båda truckmodellerna. Tillräcklig utbildning för att bedömma skadade truckdäck saknas stora delar av dygnet, resursbrist kan förekomma i truckverkstaden samt otydliga direktiv råder mellan arbetsgrupper hur kommunikationen skall förmedlas vilket förlänger nedtiderna. I syfte att optimera underhållssäkerheten bör tydliga rutiner mellan arbetsgrupperna skapas, vidare bör utbildningen utökas till berörda arbetsgrupper vilket innebär att bedömning av däckskador kan ske oavsett tid på dygnet. Arbetsfördelningen för de inblandade arbetsgrupperna bör omfördelas för att skapa en mer effektiv underhållskedja. Utifrån funktionssäkerheten visade studien att den nyare truckmodellen har större problem med däckskador än den äldre truckmodellen. Av de truckdäck där drifttiden analyserats visade sig ett av däckmärkena ha för korta drifttider jämfört med Bolidens internt uppsatta gränsvärden. Underhållsmässigheten visade att den nyare truckmodellen är svårare att underhålla eftersom komponenterna är större samt att utrustning saknas för att utföra fler än ett däckbyte samtidigt. I övrigt har Boliden två olika avtal gällande däck och studien presenterar förändringar i dessa som möjliggör att företaget ska kunna höja tillgängligheten. För att kunna göra bättre kartläggningar och analyser om underhållskedjan utifrån underhållsdata kring däckskador på truckarna bör företaget skapa bättre rutiner för inrapportering och dokumentation. / Boliden Mineral AB is a mining company producing metals for the modern society. The company have two open-pit mines in Aitik, situated in Gällivare in the northern part of Sweden. One of these open-pit mines is the largest in the country. Two models of large mining trucks transports ore from the mine to the concentrator where copper and other metals are recovered. The trucks play a key role in the logistics of ore, therefore their availability affect the total production capabilities of the mine. Damaged truck tires is one of the main reasons of downtime of the trucks. The aim of this study was to present a status report of the maintenance chain regarding damaged truck tires in the company and give suggestions about changes in tire maintenance to obtain better availability for the trucks regarding damaged truck tires. The study is based on interviews with workers from different working places who are involved in the maintenance chain as well as studies of maintenance data regarding truck tires. A RAMS (Reliability, Availability, Maintainability and Supportability) analysis was performed in order to discover causes of breakdown and bottlenecks in supportability, maintainability and reliability in the maintenance chain, all of which affect the availability of the plant. Findings in the RAMS analysis demonstrated that most bottlenecks were found in the supportability of the maintenance organization underlining unsatisfactory reaction times during tire breakdowns. The study further exposed the fact that downtime on behalf of damaged truck tires is too long in comparison to the ideal times achievable for the organization. Main causes to this problem is the fact that educated personnel with sufficient knowledge to inspect tire damage is missing most of the day, occasional resource shortages in the truck workshop as well as uncertainty in the communication between different working places which increases the downtime. To optimize the supportability of the maintenance chain the company have to introduce clear routines between the different departments and make sure that necessary education is provided to all sectors so that inspections are possible at any time. The study shows that the reliability for the newer truckmodel have greater problems with damaged truck tires compared to the older model. The lifespan for one of the analyzed truck tires in the study was shorter than the limit put up by the company. The analysis regarding the maintainability displayed the fact that maintenance is more difficult to perform because of larger components. The workshop have merely one device to perform multiple tire changes at the same time which also increases the downtime. This study underlines the fact that changes in the two existing agreements for truck tires may increase availability of the trucks for the company.

I Aitiks dagbrottsgruva i norra Lappland bryts kopparmalm med hjälp av metoden pallbrytning. I korthet innebär det att omkring 200 borrhål borras vertikalt i berget och fylls senare med sprängämne. Vid detonationen frigörs en horisontell skiva, så kallad pall, från det omgivande berget. Aitik använder i dagsläget sin borrplan för bestämning av borrhålens längd. Emellertid överensstämmer inte alltid dessa längder med de önskvärda borrhålslängderna. Målet med projektet var att föreslå förbättrade metoder och tillvägagångsätt för att nå önskad nivå vid produktionsborrning. Under projektet har det studerats hur mycket borrplanen avviker från önskade borrhålslängder. Det har också undersökts i vilken utsträckning borrmaskinerna autonomt klarar av att beräkna korrekta hål-längder med hjälp av sitt navigationssystem. En borrmaskin i Aitik använder Trimbles navigationsplattform medan de övriga fyra använder Leica. Analyserna visade att Trimbles navigationssystem var mycket tillförlitligt att använda för hål-längdsbestämning, förutsatt att noggrann kalibrering utförts. Leicas navigationssystem visade sig vara mindre tillförlitligt, då det ”svajade” i höjdled: för samma punkt i rummet visades olika höjdledskoordinater vid olika tidpunkter. Den Leica-utrustade borrmaskinen som svajade mest hade variationsbredden 31,9 cm. Rekommendationerna är: * Att om borrplanen fortsättningsvis ska användas för hållängdsbestämning, rekommenderas att ”nollning” av borrmaskinen skall ske utan rotation. Nollning är den punkt som bestäms till borrstartspunkt under borrningens utförande. Våra tester visade att om nollning sker med rotation, kan borrkronan sjunka ned 20 cm i pallytan innan borrstart registreras. På grund av detta kan borrhålen bli för långa. * Att under en testperiod, låta navigationssystemet på maskinerna autonomt beräkna borrhålens längd. Under denna period bör regelbundna kontroller av navigationssystemet ske, för att säkerställa att höjdkoordinaterna håller sig inom bestämda gränser. Kontrolleras maskinernas navigationssystem regelbundet kan ett stort statistiskt underlag skapas, vilket kan användas vid ett långsiktigt beslut om navigationssystemet fortsättningsvis skall användas för bestämning av borrhålslängder. / In the open pit mine Aitik, situated in the north of Lapland, copper ore is mined using the method pallet mining. In short, around two hundred boreholes are drilled vertically into the rock and subsequently filled with explosives. At detonation, a horizontal slice called a pallet is released from the surrounding rock. Today Aitik uses a drilling plan to decide the lengths of the boreholes. However, these lengths do not always correspond with the desired borehole lengths. The goal with the project was to find and suggest better methods and approaches to achieve desired levels of production drilling. During the project, studies have been made to see how much the drilling plan differs from the desired borehole lengths. The studies have also concerned the extent to which the drilling machines can make autonomic decisions determining the borehole lengths, using their navigation system. One drilling machine in Aitik uses a Trimble platform for navigation, while the other four use Leica. The analysis shows that the Trimble navigation platform was very reliable in deciding borehole lengths, provided that an accurate calibration was performed. The Leica navigation system turned out to be less reliable, since its height readings fluctuated: the same point in space would show as different coordinates of height at different points in time. The Leica-equipped power drill with the most fluctuation had a variation width of 31,9 cm. The recommendations are: * That, in the case of continuous use of the drill plan to determine borehole length, the “zero setting” of the power drill shall be made without drill rotation. The zero setting is starting point of the drilling operation. The tests showed that if the zero setting is done with rotation, the drill crown can sink 20 cm down into the pallet surface before drill start is registered. Because of this, the drilling holes can become too long. * That, during a test period, the navigation systems of the machines shall autonomously calculate and decide the borehole length. During this period, regular controls of the navigation systems should be made to ascertain that the coordinates of height remain within certain limits. Regular controls of the navigation systems can provide large amounts of statistical data, which can be used to make a long-term decision whether the navigation systems should continue to determine the borehole lengths.

Den här studien utgår ifrån två svenska koppargruvor varav den ena, Aitik i Gällivare, är idrift och den andra, Falu gruva, stängde 1992. Studiens syfte är att undersöka förutsättningarna för att använda Falu gruva som modell för den framtida avvecklingen av Aitik, med särskilt avseende på efterbehandling, kulturarvsprocesser och återanvändning. Inom ramen för kulturarvsprocesser och återanvändning beaktas särskilt lärande.Metodansatsen är kvalitativ och den teoretiska utgångspunkten är att en gruva kan ses som ett stort sociotekniskt system bestående av artefakter och sociala komponenter. Genom intervjuer med representanter från Falu gruvas ägare och Aitiks ägare samt från Gällivare kommun genererades data. Data från intervjuerna samt från en mindre dokumentstudieut gjorde studiens resultat. Detta analyserades tematiskt och diskuterades utifrån uppsatsens teoriavsnitt. Resultatet visar att Aitik kan utvecklas vid en framtida avveckling och att Falu gruva i vissa avseenden kan användas som modell för denna process. Bland annat kan Falu gruva användas som modell för Aitik avseende utbildning som en del av återanvändning, där Aitikkan lära av Falu gruva genom att inte göra samma misstag som gjorts där. Resultatet visar emellertid också att samhällena Gällivare och Falun skiljer sig mycket åt, både vad gäller samhällsidentitet och samhällets relation till gruvan. Slutsatsen av den här studien är att aspekter såsom att betrakta artefakter som en resurs; gruvans roll i samhället; samt vem som definierar kulturarv är centrala för att kunna använda Falu gruva som modell för Aitikmed hänsyn till lärande. / This study is about two Swedish copper mines, Aitik in Gällivare which is still in use and theFalun mine, which closed in 1992. The aim of this study is to explore the prerequisites for using the Falun mine as a model for the future closure of the Aitik mine, with regards specifically to mine reclamation, heritagisation and reuse. In particular, the aspect of learning within the heritagisation and reuse framework is discussed. A qualitative research method has been used and the theoretical starting point is that a mine can be seen as a large technological system consisting of artifacts and social components. Data has been collected through interviews with representatives from the Falun mine owners, the Aitik mine owners and from the local government of Gällivare. This data, along with data from a limited document study, made up the results of this study. The results were then analyzed thematically and discussed against the theoretical frameworks used in this study. The results show that Aitik can be developed post-closure and that the Falun mine can, ins ome regards, be used as a model for this development process. Among other aspects, theFalun mine can be used as a model for Aitik for education as a part of reusing the mine, where Aitik can learn from the Falun mine by not making the same mistakes that were made there. However, the results show that the Gällivare and Falun societies are different in terms of identity and in their relations towards the mines. The conclusion of this study is that aspects such as regarding artifacts as resources; the mine’s role in society; and who determines what a cultural heritage is, are all important in order to use the Falun mine as a model for Aitik from an educational perspective.

Rock blasting is one of the most dominating operations in open pit mining efficiency. As many downstream processes depend on the blast-induced fragmentation, an optimized blasting strategy can influence the total revenue of a mine to a large extent.Boliden Aitik mine in northern Sweden is one of the largest copper mines in Europe. The annual production of the mine is expected to reach 36 million tonnes of ore in 2014; so continuous efforts are being made to boost the production. Highly automated equipment and new processing plant, in addition to new crushers, have sufficient capacity to reach the production goals; the current obstacle in the process of production increase is a bottleneck in crushers caused by oversize boulders. Boulders require extra efforts for secondary blasting or hammer breakage and if entered the crushers, they cause downtimes. Therefore a more evenly distributed fragmentation with less oversize material can be advantageous. Furthermore, a better fragmentation can cause a reduction in energy costs by demanding less amounts of crushing energy.In order to achieve a more favorable fragmentation, two alternative blast designs in addition to a reference design were tested and the results were evaluated and compared to the current design in Aitik. A comparatively large bench was divided to three sections with three different drill plans, which led to different specific charges in each section. The sections were drilled in patterns of 6x9 m, 7x9 m and 7x10 m of burden and spacing; planned specific charges of the sections were 1.17 kg/m3, 1.02 kg/m3, and 0.91 kg/m3 respectively. Similar to the current drill plan in Aitik, the section with 7x9 m (1.02 kg/m3 specific charge) was used as the reference for results comparison. The drilling and charging processes were monitored carefully and the post-blast parameters were measured accordingly. Laser scanning was used to measure the swelling of the sections and two different methods of image analysis were utilized to evaluate the fragmentation of the rock for each section. Drilling log data (MWD) were analyzed to evaluate the hardness of the rock; energy consumption log of the crusher was also analyzed and all the data was collected in a single database. VBA (Visual Basic for Applications) programming language was embedded within data spreadsheets to correlate the mentioned data to the coordinates of the rock by means of Minestar logs, which include both timestamps and coordinates of all machinery e.g. shovels and trucks.The results of the test show significant improvements in fragmentation and oversize material percentage in the section with 6x9 m drill plan (1.17 kg/m3). The advantage of 6x9 m plan was confirmed by 52% higher swelling, 66% lower oversize material and 26% lower crushing energy compared to the reference section. The section with 7x10 m drill plan (0.91 kg/m3) also showed theoretically acceptable results; however, the deviations from reference were not as large as formerly mentioned section. The swelling had a decrease of 8% compared to the reference section and the percentage of oversize material and crushing energy were increased by 16% and 2% respectively.Presented results are based only on technical aspects and do not include the costs of drilling and charging. Thus, in order to evaluate the drill plans in practice an economical evaluation of the sections should be conducted. Also a confirmation test with more accurate geology explorations is recommended.Finally, upon the request of Boliden Mines, a short report on the usage of Air-decking technique in Aitik is enclosed as an appendix. The report includes a brief introduction to air-decking and discusses practical solutions to apply this technique in Aitik. / Validerat; 20121001 (anonymous)

The Aitik Mine is the largest copper mine in Europe and every year, 15 – 20 Mt waste rock is deposited in dumps located close to the mine. This waste rock can contain sulfides, which if exposed to oxygen can cause leeching and formation of acid rock drainage. To prevent this from happening, Boliden has designed a dry cover system to prevent leaching from occurring. The purpose of this study was to characterize existing stockpiles of till at Boliden’s Aitik Mine site in the context of requirements for the closure cover system. The till was evaluated primarily of its suitability for use in a highly compacted layer (HCL), since Boliden has a cover system design that has to provide the necessary control on oxygen diffusion rates to underlying waste rock material over the long term. The sampling took place on three of the stockpiles and a total of 31 test pits were excavated. A total of 27 samples of soil were collected and analyzed for particle size distribution (PSD) testing. Following review of PSD results, select samples were tested for hydraulic conductivity and compaction testing. The PSD results showed that all materials were fine-grained sand with some gravel, cobbles and silt. Results also show the amount of clay particles (0,004 mm) were relatively low across the three stockpiles. The result for the hydraulic conductivity were higher than Boliden’s prescriptive criteria. The results indicate that the sampled till would require addition of sodium bentonite to be able to construct a HCL with a hydraulic conductivity not exceeding Boliden’s criteria.

Detta examensarbete handlar om att följa upp skuthantering i Aitik och dess ekonomiska påverkan, Aitik är en dagbrottsgruva som ligger i Gällivares kommun. Skut är ett bergblock som är större än 1 m3 och är ett återkommande problem då de orsakar störningar i produktionsflödet. Totalt genomfördes tre fältstudier som inriktades på lastning, skutknackning och kross. Ett utav målen var att undersöka om det är lönsamt att låta Aitiks entreprenör knacka skut, detta genom att jämföra kostnaden som entreprenören fakturerar mot att hantera skuten som gråberg vilket medför en deponiförlust av kopparvärdet. Hantering av skut kan ske på två olika sätt, hantering vid upplag och hantering vid salva. Dessa två metoder jämförs för att se vilken som är mest lönsam. Ett annat mål var att undersökahur stor inverkan skut har i krossen då de orsakar stopp, och därefter jämföra dessa stopporsaker mot krossoperatörens inrapporterade stopporsak, vilket denne gör i Aitiks Sogetisystem. Studien åskådliggör att det inte är lönsamt att låta entreprenören hantera skut vid kopparhalten 0,06 %. För kopparhalter kring 0,1 % bör vidare undersökningar genomföras om det är lönsamt eller ej. Vid 0,2 % och över är det lönsamt med skuthantering från entreprenören. Skuthantering vid upplag är den mest lönsamma metoden så länge dieselpriset understiger 10 kr per liter. Skut har en stor negativ inverkan på produktionseffektiviteten i krossen. Totalt orsakades 86 minuter stopp i krossen på grund av skut under två skift. Detta motsvarar ca 400 000 kr i produktionsförlust, vid produktionseffektiviteten 4041 ton per timme vilket var den verkliga effektiviteten hos krossen under det ena skiftet. Olikheter påträffades vid jämförelse mellan dokumenterade stopporsaker och operatörernas stopporsaker i Sogeti. Vid uppföljande studier bör hänsyn tas till kostnader för truckslitage i beräkningar av skuthantering, då detta kan påverka resultatet. Fler fältstudier bör utföras för att få ett mer tillförlitlig resultat. / This thesis is about following up the handing of boulders and its economic impact. Aitik is an open-pit mine located near Gällivare in Norrbotten. According to Aitik, a boulder is a rough stone that is larger than 1 m3, and they are a recurrent problem because boulders cause a disturbance in the production flow. A total of three field studies were done which focused on loading, boulder breaking and crushing. The goal was to investigate if it was going to be profitable to let Aitik´s entrepreneur handle boulders using a hydraulic breaker, thus comparing the invoice from Aitik´s entrepreneur compared to handling the boulders as waste rock, which entails a landfill loss of the copper value. The handling of boulders can occur in two different ways, handling at stockpile or handling at burst. These two methods are compared with each other to see which one is the most profitable. Beyond this it was also examined on how much of an impact boulders have in the crushing section when they cause a stop, and thereafter compare these stops against the reported stoppage from the operators which is done in Aitiks Sogetisystem. The study illustrates that it is not profitable to let Aitik´s entrepreneur handle boulders at the copper content 0,06 %. Copper concentrations around 0,1 % should be further analyzed whether it is profitable or not. At 0,2 % and above it is profitable to let Aitik´s entrepreneur handle the boulders. Handling boulders at stockpile is the most profitable method as long as the fuel cost is below 10 SEK per liters. Boulders have a large negative impact on the production efficiency in the crushing section. In two shifts there were a total of 86 minutes stop in the crusher caused by boulders, this corresponds to about 400 000 SEK in production loss at a production efficiency of 4041 tons per hour, which was the actual efficiency during one of the shifts. Differences occurred among the documented stop causes and the stop causes made by the operators in Sogeti. For further studies, a regard should be made occurring costs of truck wear due to boulder handling as this may affect the results. Also perform more field studies in order to get a more reliable result.

Commodity projection studies anticipate an exponential increase in copper demand and decreasein mill grade of deposits currently exploited globally. Most of this demand is driven by theindispensable use of copper in electrification and currently, the growing demand in the contextof the green transition. To meet this challenge while supplying society with copper, producerssuch as Boliden AB have plans for exploration and expansion projects to increase their reservesand in turn increase production through efficient measures. As grinding is a bottleneck to mineralprocessing and the most energy intensive, more efficient comminution systems are beingconsidered for environmental sustainability. These are required to have lower energyconsumption while achieving the required liberation or better for subsequent processing byflotation. Consequently, the literature review shows there is a research query on whether more can beexpected from comminution to optimise for downstream processing. With most publishedresearch being on particles with a P80 less than 100 μm, there exists a gap in investigating theeffect of grinding on flotation for coarser size fractions which this degree project focuses on.Importantly, it includes evaluating chalcopyrite liberation and flotation performance when usinga Novel Comminution Device. Three grinding mills were considered, a vertical roller mill (VRM),a Novel Comminution Device (NCD), with a rod mill as the reference mill. The scope of this studywas an analysis of the mill products’ particle size distribution, chalcopyrite liberation andinvestigation of the flotation performance of the products from the three mills. This was done ona Cu-Au-Ag ore from the Boliden Aitik mine in northern Sweden. Particle size distribution (PSD) analysis revealed that at comparable P80 values, the VRMproduced particles had broader PSD curves than the rod mill, while the NCD provided a steeperproduct size distribution than its reference rod mill products. The chalcopyrite liberation analysisusing QEMSCAN automated mineralogy showed that for samples split into three size fractions, -45 μm, +45/-90 μm and +90 μm, the VRM and rod mill products had their highest proportion offree to liberated particles within the intermediate size fraction while for the NCD sample this waswithin the fine fraction. Overall, the NCD product had the highest free to liberated particles acrossall fractions. From shape analysis based on scanning electron microscopy (SEM) images, it wasobserved that the NCD produced particles with the higher elongation than the VRM and rod mill. The flotation performance was assessed with respect to the mass pull, kinetics, grade andrecovery in the concentrate and separation efficiency. The rougher batch flotation tests indicatedthat flotation of the VRM ground samples had higher mass pull, Cu recovery, faster kinetics andlower Cu grade than the samples from the reference rod mill. This was also a similar outcome forthe NCD with the exception of higher mass pull at an increased collector dosage in the rod millcase. For all the mills, the general trend showed that an increase in P80 was associated withreduced mass pull. Overall, at similar flotation conditions, despite having one of the coarsest P80s,the NCD product showed the fastest Cu recovery kinetics, highest total recovery and selectivityindex. The rod mill reference test samples gave the highest grade but the lowest recovery. The findings illustrate that there is a significant difference in PSD broadness between productsfrom different mills at comparable P80. The differences in flotation performance between thethree mill products were mainly attributed to differences in liberation, potential differences insurface activation between wet and dry grinding methods and to some extent, steepness of thePSD curve. Based on the high recovery yet low grade of the NCD ground product, this is best suitedfor the rougher flotation stage. Future studies should therefore include cleaner stage flotation andoptimisation tests for the NCD with respect to reagent dosages and hydrodynamic conditions.