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For the first time, we apply a full-scale 3D seismic virtual-source survey (VSS) for the purpose of near-mine mineral exploration. The data were acquired directly above the Kylylahti underground mine in Finland. Recorded ambient noise (AN) data are characterized using power spectral density (PSD) and beamforming. Data have the most energy at frequencies 25-90gHz, and arrivals with velocities higher than 4gkmgs-1 have a wide range of azimuths. Based on the PSD and beamforming results, we created 10gd subset of AN recordings that were dominated by multi-azimuth high-velocity arrivals. We use an illumination diagnosis technique and location procedure to show that the AN recordings associated with high apparent velocities are related to body-wave events. Next, we produce 994 virtual-source gathers by applying seismic interferometry processing by cross-correlating AN at all receivers, resulting in full 3D VSS. We apply standard 3D time-domain reflection seismic data processing and imaging using both a selectively stacked subset and full passive data, and we validate the results against a pre-existing detailed geological information and 3D active-source survey data processed in the same way as the passive data. The resulting post-stack migrated sections show agreement of reflections between the passive and active data and indicate that VSS provides images where the active-source data are not available due to terrain restrictions. We conclude that while the all-noise approach provides some higher-quality reflections related to the inner geological contacts within the target formation and the general dipping trend of the formation, the selected subset is most efficient in resolving the base of formation., Applied Geophysics and Petrophysics

We use self-organizing map (SOM) analysis to predict missing seismic velocity values from other available borehole data. The site of this study is the Kevitsa Ni-Cu-PGE deposit within the mafic-ultramafic Kevitsa intrusion in northern Finland. The site has been the target of extensive seismic reflection surveys, which have revealed a series of reflections beneath the Kevitsa resource area. The interpretation of these reflections has been complicated by disparate borehole data, particularly because of the scarce amount of available sonic borehole logs and the varying practices in logging of borehole lithologies. SOM is an unsupervised data mining method based on vector quantization. In this study, SOM is used to predict missing seismic velocities from other geophysical, geochemical, geological, and geotechnical data. For test boreholes, for which measured seismic velocity logs are also available, the correlation between actual measured and predicted velocities is strong to moderate, depending on the parameters included in the SOM analysis. Predicted reflectivity logs, based on measured densities and predicted velocities, show that some contacts between olivine pyroxenite/olivine websterite-dominant host rocks of the Kevitsa disseminated sulfide mineralization-and metaperidotite-earlier extensively used "lithology" label that essentially describes various degrees of alteration of different olivine pyroxenite variants-are reflective, and thus, alteration can potentially cause reflectivity within the Kevitsa intrusion.

Kevitsa is a disseminated Ni-Cu-PGE (platinum group elements) ore body in northern Finland, hosted by an extremely high-velocity (6.5-8.5 km/s) ultramafic intrusion. It is currently being mined at a depth of approximately 100 m with open-pit mining. The estimated mine life is 20 years, with the final pit reaching a depth of 500-600 m. Based on a series of 2D seismic surveys and given the expected mine life, a high-resolution 3D seismic survey was justified and conducted in the winter of 2010. We evaluate earlier 3D reflection data processing results and complement that by the results of 3D first-arrival traveltime tomography. The combined results provide insights on the nature of some of the reflectors within the intrusion. In particular, a major discontinuity, a weakness zone, is delineated in the tomography results on the northern side of the planned pit. Supported by the reflection data, we estimate the discontinuity, likely a thrust sheet, to extend down approximately 600 m and laterally 1000 m. The weakness zone terminates prominent internal reflectivity of the Kevitsa intrusion, and it is associated with the extent of the economic mineralization. Together with other weakness zones, a couple of which are also revealed by the tomography study, the discontinuity forms a major wedge block that influences the mine bench stability on the northern side of the open pit and likely will cause more issues during the extraction of the ore in this part of the mine. We argue that 3D seismic data should routinely be acquired prior to commencement of mining activities to maximize exploration efficiency at depth and also to optimize mining as it continues toward depth. Three-dimensional seismic data over mineral exploration areas are valuable and can be revisited for different purposes but are difficult to impossible to acquire after mining has commenced.

The Kevitsa Ni-Cu-PGE disseminated sulphide deposit is hosted by the Kevitsa mafic to ultramafic intrusion, located within the Central Lapland Greenstone Belt in northern Finland. A 3D seismic reflection survey was conducted in Kevitsa in 2010 for mine planning and deep mineral exploration purposes. Within the Kevitsa resource area, the 3D seismic data are characterized by laterally continuous reflections. Here we use data mining, namely Self-Organizing Map (SOM), analysis to better understand the possible causes of reflectivity within the Kevitsa intrusion. The results show that the mineralized zones within the intrusion could be potential causes of reflectivity, and hence could set potential exploration targets in the area.

Effective exploration for mineral deposits depends on a sound understanding of the processes and geological structures that contributed to their formation. The reflection seismic method has proven to be a powerful tool that provides a high-resolution image of the subsurface and information about structural and lithological relationships that control mineral deposits. The method has also become an attractive geophysical tool for deep exploration and mine planning. In this paper, we review the use of reflection seismic methods to obtain a better understanding of the architecture and ore-forming processes of three diverse mineral regions: the Kevitsa Ni-Cu-PGE district in Finland, the goldfields of the Witwatersrand Basin South Africa, and the Bathurst Mining Camp, Canada. Seismic data, both 2D and 3D, from the Kevitsa deposit clearly image the 3D geometry of the ore-bearing intrusion and provide information about its relationship to the host rock units and nearby intrusions within a larger tectonic framework. 3D seismic data from the Witwatersrand Basin not only provide clear images of major structures, including a distinct reflection that acts as a marker horizon for the gold-bearing reef, but also provide information that may be useful in resolving a long-standing controversy regarding the origin of the gold in the Basin. For example, it might be possible to show that dykes formed impermeable barriers, thereby falsifying the epigenetic hydrothermal models. 2D and 3D seismic data from the Brunswick No. 6 area in the Bathurst Mining Camp suggest that the Brunswick horizon (which contains the bulk of the massive sulfide and associated iron deposits) occurs within a reflective package that extends down to at least 6-7 km depth.

The Kevitsa mafic-ultramafic intrusion in northern Finland hosts a large, disseminated nickel-coppersulphide deposit. We present a 3D lithological and structural model of the Kevitsa area, obtained viamodeling of 2D and 3D reflection seismic data from Kevitsa. The Kevitsa 3D model contains modeledsurfaces of the contacts between the main lithological units and a model of the magmatic layering withinthe intrusion. The Kevitsa main mineralization is thought to be controlled by the lateral extents of thisdiscontinuous, smaller-scale magmatic layering within the intrusion. An improved knowledge of thegeometry of the intrusion, and in particular of the extent of the internal magmatic layering, provides aframework for near-mine and deep exploration in the area. Better control on the position of the basalcontact of the intrusion provides an exploration target for the contact-type mineralization. The originalpurpose of the 3D seismic survey was to provide a structural framework for geotechnical planning of themine, and accordingly the 3D seismic data were used to create a structural model of the 3D cube. Themodeled structures reveal a complex pattern of fault and fracture zones, some of which will be importantfor slope stability and operational planning at the mine.

A 3D reflection seismic survey was conducted over an area of about 9 km(2) at the Kevitsa Ni-Cu-PGE (platinum group elements) orebody, northern Finland, where open-pit mining started in mid-2012. The principal objective of the survey was to image major fault and fracture zones at depth that may have an impact on the mine stability and safety. Mine planning would then take into account the geometry of these zones at Kevitsa. Processing results, using conventional prestack DMO and poststack migration methods, show gently dipping and steeply dipping reflections from depths of approximately 2 km to as shallow as 150-200 m. Many of the reflections are interpreted to originate from either fault systems or internal magmatic layering within the Kevitsa main intrusion. Further correlation between the surface seismic data and VSP data suggests that numerous faults are present in the imaged volume based upon time shifts or phase changes along horizontal to gently dipping reflections. Some of these faults cross the planned open-pit mine at depths of about 300-500 m, and are therefore critical for geotechnical planning. In terms of in-pit and near-mine exploration, the magmatic layering internal to the intrusion controls the distribution of the bulk of economic mineralization. The ability to image this magmatic layering could therefore guide future drilling, particularly by constraining the presumed lateral extents of the resource area. Exploration also will target discrete reflectors that potentially represent higher-grade sulfide mineralization.

In 2007, a 2D reflection seismic survey was conducted at the Kevitsa Ni-Cu-PGE (platinum group elements) deposit in northern Finland. The aims of the survey were to delineate the overall extent of the ore-bearing Kevitsa ultramafic intrusive complex, to study the seismic response of the disseminated ore deposit, to potentially find indications for new ore deposits, and to extract structural information at depth that may be associated with mineralization. In the processing sequence, specific focus was given to finding optimal CDP-line geometries for the crooked-line survey profiles and, due to highly variable bedrock velocities, to detailed velocity analysis. Our conventional processing sequence, involving prestack DMO corrections followed by poststack migration, resulted in high-quality images of the subsurface. First, the data were used to establish the shape and extent of the Kevitsa intrusion, thus providing an overall framework for future exploration in the area. In particular, the data suggest deeper, up to about 1.5 km depth, continuation of the intrusion than previously thought. Furthermore, the images reveal variable reflectivity characteristics within the intrusion from nonreflective to internally reflective. The Kevitsa deposit is located within a part of the intrusion which is associated with distinct, gently dipping reflectivity fabric down to a depth of about 1 km, spatially constrained within a restricted zone internal to the intrusion. This zone can be used as a guideline for the near-mine exploration efforts, and the reflectivity is dominantly associated with magmatic layering controlling the extent of the bulk of economic mineralization. The seismic data also reveal a complex pattern of faults, in particular a series of major fault and shear zones bracketing and crosscutting the Kevitsa intrusion as a whole. Additionally, our interpretation of the data indicates a possible shared origin of the Kevitsa intrusion and the nearby Satovaara intrusion.

Tulevaisuudessa suuri osa innovaatioista syntyy palvelualoilla. Vaikka yksityinen palvelusektori on suurin ja nopeimmin kasvava osa teollisuusmaiden elinkeinoelämää, palveluinnovaatiot ovat vielä hyvin tuore tutkimusalue. Tämä tutkimus edustaa laadullista soveltavaa tutkimusta, jonka tutkimusotteina käytettiin konstruktiivista, case- ja toimintatutkimusta. Konstruktiivinen tutkimusote oli tutkimuksen pääasiallinen tutkimusote. Tutkimuksessa selvitettiin, miten suunnitteluvaiheen sujuvuutta voidaan edistää strategisen allianssin palvelutuotekehityksessä. Kirjallisuustutkimus kohdistettiin palveluita, innovaatioita, strukturoitua palvelutuotekehitystä ja strategisia alliansseja käsittelevään teoriaan. Näistä osa-alueista tehtiin synteesi eli teoreettinen konstruktio. Teoreettista konstruktiota kehitettiin edelleen empiirisen tutkimuksen avulla, jossa käsiteltiin pankki- ja vakuutustoimialalla toimivaa allianssia. Tutkimuksen tuloksena esitettiin suunnitteluvaiheen malli. Tärkeimmiksi suunnitteluvaihetta edistäviksi tekijöiksi osoittautuivat ns. lähtökohtatekijät, suhdeverkosto ja kehitysprosessi. Tutkimuksen teoreettiset kontribuutiot liittyvät tarjoomakehitykseen, suhdeverkostoon ja kehitysprosessiin. Allianssin yhteisen palvelukehityksen tulee olla tavoitteellista toimintaa, joka pohjautuu organisaatioiden strategisiin valintoihin. Organisaatioiden asiakkuusajattelut huomioimalla voidaan herättää organisaatioiden mielenkiintoa kehittää yhteistä tarjoomaa. Toimiva suhdeverkosto on puolestaan edellytys kaikelle yhteistyölle. Suhdeverkostoa tukee johtamismalli, joka painottaa avoimuutta, luottamusta sekä positiivista asennetta yhteistyötä kohtaan. Viimeinen teoreettinen kontribuutio liittyy kehitysprosessiin, jossa erityisesti yhteinen strategiatyöskentely ja ideointivaihe korostuvat. Yhteistyö on sidottava osaksi organisaatioiden olemassa olevaa toimintaa.