GEOLOŠKO-GEOFIZIČKA ISTRAŽIVANJA LEŽIŠTA BOKSITA PRIMJENA PLITKE SEIZMIČKE REFLEKSIJE

The exploration of bauxite deposits in the region of the carbonaceous Dinarides has been performed by using different geological and geophysical methods. Deposits laying shallower or deeper below the roof sediments have so far most often been discovered by expensive drilling methods in a corresponding grid. Complex geological explorations have led to a series of valuable data thus enabling the application of other much more economical methods as well. In the region of the bauxite sedimentary basin Mesihovina-Rakitno, western Herzegovina, at the site of Studena vrila - after extensive geological explorations - a conclusion was drawn that the shallow seismic reflection geophysical method as well might be successfully applied in locating new bauxite deposits. In the paper, the geological framework of the bauxite deposits occurrences, stipulating the selection of this methode, will be presented. Measurements were performed on a known deposit (L-84, Povaljenica), completely defined by exploration drilling. The obtained results justify the selection of the shallow seismic reflection method as one of the methods for exploring bauxite deposits beneath the roof beds.Istraživanje ležišta boksita, u području karbonatnih Dinarida. obavlja se uz pomoć različitih geoloških i geofizičkih metoda. Ležišta pliće ili dublje ispod krovinskih sedimenata do sada su najčešće pronalažena skupim metodama bušenja u odgovarajućoj mreži. Kompleksnim geološkim istraživanjima došlo se do niza vrijednih podataka koji omogućuju primjenu i drugih ekonomičnijih metoda. U području boksitonosnog sedimentacijskog bazena Mesihovina - Rakitno. zapadna Hercegovina, na lokalitetu Studena vrila nakon obimnih geoloških istraživanja došlo se do spoznaje da bi se pri pronalaženju novih ležišta boksita mogla s dosta uspjeha koristiti i geofizička metoda plitke seizmičke refleksije. U radu su izloženi geološki okviri pojavljivanja ležišta boksita koji su uvjetovali odabir ove metode. Mjerenja su izvedena na poznatom ležištu (L-84, Povaljenica) koje je u potpunosti definirano istražnim bušenjem. Dobiveni rezultati opravdavaju izbor plitke seizmičke refleksije kao jedne od metoda kod istraživanja ležišta boksita ispod krovinskih naslaga

MORFOLOŠKI I GEOLOŠKI POKAZATELJI MOGUĆIH LEŽIŠTA BOKSITA U KRAŠKOM PODRUČJU ZAPADNE HERCEGOVINE

Investigation results of morphological and geological potential bauxite deposit indicators in the Mesihovina-Rakitno bauxitebearing sedimentary basin in Western Herzegovina are presented. Region with carbonate and clastic hangingwalls as well as those without overlying sediments have been studied. It was established that the expression and number of the indicators depend size as well as on character and thickness of hangingwall sediments. The morphological indicators are expressed as a particular relief forms situated right above the deposits or nearby and are a consequence of geological relations and exodynamic processes. Ihe numerous geological indicators resulted from complex geological events. The most important are: preore structural relations, the formation of paleorelief, peculiar way of hangingwall rocks sedimentation, lithification processes and the formation of the recent structural pattern. It has been observed that particular indicators should be recognized within a relatively thick succession of the overlying sediments which is of the great importance in the exploration of bauxite deposits.U radu su prikazani rezultati istraživanja morfoloških i geoloških pokazatelja mogućih ležišta boksita u boksitonosnom sedimentacijskom bazenu Mesihovina-Rakitno Proučavana su područja s karbonatom i klastičnom krovinom, te predjeli bez krovinskih naslaga. Ustanovljeno je da izraz i brojnost pokazatelja ovisi o veličini ležišta, te debljini i karakteru krovinskih sedimenta. Morfološki pokazatelji očituju se kao specifični oblici iznad ležišta boksita ili u njihovoj blizini. Uočeno je da su oni rezultat geoloških odnosa i egzodinamskih procesa. Brojni geološki pokazatelji su rezultat kompleksnih geoloških zbivanja. Najvažniji su: predrudni strukturni odnosi, formiranje paleoreljefa, specifičan način sedimentacije krovinskih naslga, procesi litifikacije i formiranje recentnog strukturnog sklopa Uočeno je da je pojedine od pokazatelja moguće prepoznati u relativno debelom slijedu krovine što im daje i veliko praktično značenje

EVALUATION OF RESEARCH IN BAUXITE-BEARING AREA ON A LOCALITY „CRVENE STIJENE“ WITH EMPHASIS ON EXPLOITATION OF ASSOCIATED DEPOSITS

In this paper we present and elaborate one example when bauxite was the main target of investigation. During reprocessing and reinterpreting original input data from locality “Crvene stijene” near Jajce in Bosnia and Herzegovina, it was established that bauxite hanging wall and footwall rocks in fact present even more valuable mineral resources, dimension stone. This paper presents results of reprocessing and reinterpretation of original data with focus not only on primary resource, but on resources that are developed in footwall and hanging wall. Final goal of the research was to optimize the ratio between research and exploration cost and total profit by exploration of all available mineral resources in the area. For that purpose, new method of bauxite (primary resource) and associated deposits is developed and named “integrated approach”. Integrated, joint evaluation of bauxite and associated deposits (dimension stone), would give far greater significance to whole area. Finally, with this new method, the ratio between overall profit and cost will be maximized. </p

HIDROGEOLOŠKO KARTIRANJE MIOCENSKOG VODONOSNIKA DVODIMENZIONALNOM ELEKTRIČNOM TOMOGRAFIJOM

Geoelectrical resistivity methods have been playing very important role in hydrogeological explorations for years, since they can provide information lithology porosity, permeability and water quality. But conventional resistivity methods, electrical sounding and electrical profiling, cannot satisfy demand for continuos coverage over an exploration area and for building of a detailed hydrogeological model, especially with complex geological models and 3-D structure shapes. Electrical sounding is based on a theoretical assumption of a horizontally stratified earth model, and electrical profiling maps only lateral resistivity changes at the same depth. Two-dimensional (2-D) electrical imaging (or 2-D electrical tomography), that has been introduced recently, can map the both vertical and lateral resistivity changes and provides for building three-dimensional (3-D) resistivity model of the underground. Exploration has been carried out in the area of the Seona spring to investigate the possibility for pumping more water during dry season, from the well located near the spring. The water of the Seona spring emerges from Badenian carbonate aquifer, which shows irregular 3-D shape and heterogeneous lithologic composition. A network consisting of four electrical profiles has been established to acquire a 3-D resistivity model, which can be transformed in a 3-D hydrogeological model. Inverse resistivity model sections revealed high resistivity zone which has been correlated with Badenian limestone by means of existing outcrops. Low resistivity zones point to the marly layers. Exploratory borehole located on the basis of electrical data has confirmed derived hydrogeological model from the electrical imaging data. Heterogeneous limestone aquifer has been uncovered at depth 8.2 – 55 m. The aquifer is weathered and karstificated with two main cavern intervals. Hydraulic connections between the caverns and the spring have been established during drilling, but also in a pump test by means of the airlift method. The presented case demonstrates great possibilities of the electrical imaging method in mapping of irregularly shaped aquifers and building of a precise 3-D hydrogeological model.Geoelektrične metode otpornosti imaju važnu ulogu u hidrogeološkim istraživanjima već godinama, jer mogu dati litološke podatke i s tim povezane šupljikavost i propusnost, ali i podatke o mogućoj zaslanjenosti vode. Međutim klasične metode otpornosti, geoelektrično sondiranje i geoelektrično profiliranje, ne mogu udovoljiti zahtjevu za kontinuiranim pokrivanjem istražnog područja i za konstruiranjem preciznog hidrogeološkog modela, napose u složenim geološkim modelima i trodimenzionalnom obliku struktura. Geoelektrično sondiranje se osniva na pretpostavci horizontalno uslojenog modela podzemlja, a geoelektrično profiliranje može kartirati samo lateralne promjene otpornosti na istoj dubini. Dvodimenzionalno (2-D) električno mjerenje (ili 2-D-električna tomografija), koja se nedavno pojavila, može kartirati i okomite i uzdužne promjene otpornosti i tako omogućiti konstruiranje trodimenzionalnog modela otpornosti podzemlja. Istraživanje je provedeno na području izvora Seona, kako bi se istražila mogućnost zahvata veće količine vode iz bušotine u okolici izvora, napose u sušnim razdobljima. Voda u izvoru Seona istječe iz badenskog karbonatnog vodonosnika koji je nepravilnog trodimenzionalnog oblika i heterogenog litološkog sastava. Postavljena je mreža od četiri profila kako bi se dobio trodimenzionalni model otpornosti, koji se može preoblikovati u trodimenzionalni hidrogeološki model. Interpretirani dvodimenzionalni modeli otpornosti su otkrili zone visokih otpornosti koje se mogu korelirati s badenskim vapnencima na izdancima. Zone niskih otpornosti ukazuju na laporovite slojeve. Istražna bušotina locirana na temelju geoelektričnih podataka potvrdila je hidrogeološki model načinjen na temelju podataka električne tomografije. Heterogeni vapnenjački vodonosnik otkriven je na dubinama 8.2-55 m. Vodonosnik je karstificiran i trošan, s dva glavna kavernozna intervala. Utvrđena je hidraulička veza između bušotine i izvora još tijekom bušenja, a napose pokusnim crpljenjem metodom “air-lifta”. Izloženi primjer pokazuje velike mogućnosti metode električne tomografije u kartiranju vodonosnika nepravilnih oblika i definiranju preciznog trodimenzionalnog hidrogeološkog model

Ship production processes air emissions analysis

Compliance with modern environmental norms and regulations is an increasingly important requirement in the shipbuilding process of ship design and construction. Related to the ship production process, volatile organic compounds (VOCs), nitric oxides and particulate matter are the main emissions of harmful gases in the shipyard. This paper analyzes air emissions from the ship production process in a shipyard. Air emissions are quantified from either in-situ measurements from emission sources, or by materials that are used in the shipbuilding process, and the acquired data from those measurements is calculated as yearly emissions. Emission quantities of VOCs, nitric oxides, carbon dioxide, carbon monoxide and particulates are analyzed regarding possible reduction techniques considering efficiency and investment costs for using these methods. In conclusion, the best available and feasible emission reduction methods are suggested, and a suggestion for achieving the goal of a net zero emission shipyard

Multi-Response Optimization in MQLC Machining Process of Steel St50-2 Using Grey-Fuzzy Technique

In this paper MQLC turning process of steel St 50-2 is presented. Experimentations were performed using Taguchi L9 orthogonal array by varying two process parameters such as oil and water quantity while other parameters such as cutting speed, feed rate and depth of cut were kept constant. Process responses that were analyzed in this paper are surface roughness Ra and resultant cutting force Frez. In order to quantify significance of each process parameter on analyzed response ANOVA was conducted. Fuzzy logic modelling technique was used to describe the effects of process parameters and to create response surface plots. Finally, in order to find out process parameters values that lead simultaneously to optimal surface roughness and resultant cutting force, multi-objective optimization of process responses was conducted by using grey relational analysis (GRA) combined with fuzzy logic technique

RESEARCH OF BAUXITE DEPOSITS FROM UNDERGROUND MINING WORKS

Rad prikazuje novi pristup istraživanju ležišta boksita iz podzemnih rudarskih radova u boksitonosnome području Bešpelj kod Jajca u Bosni i Hercegovini. U razmatranome području ležišta boksita istražuju se i eksploatiraju preko 60 godina. Usprkos visokomu stupnju istraženosti u geološki zamršenim strukturama Bešpelja nalaze se brojna do kraja neistražena ležišta. Ona su do sada uglavnom istraživana bušenjem s površine u mreži bušotina kako to diktiraju zakonski propisi. Zbog povećanja dubina na kojima su smještena ležišta, a i zamršenih strukturnih odnosa, takva istraživanja postala su skupa i manje učinkovita. S geološkoga stajališta ležišta boksita primarno se nalaze u vodoravnome položaju. No dugotrajna geološka evolucija od gornje krede do danas dovela je ležišta u vrlo različite strukturne položaje. Zato ih nalazimo u nagnutome položaju, u subvertikalnome i vertikalnome te nerijetko u inverznome položaju. K ako bi daljnja istraživanja postala racionalna i učinkovita, razvijen je novi pristup istraživanja iz podzemnih rudarskih radova koji će poslužiti za istraživanje i potom za eksploataciju boksitnih ležišta.The paper presents a new approach to exploring bauxite deposits from underground mining works in the bauxites area of Bešpelj near Jajce in Bosnia and Herzegovina. In the area considered, bauxite deposits are being investigated and exploited over 60 years. Despite the high degree of exploration in the geologically intricate structures of Bešpelj there are numerous up to the unexplored reservoirs. Up to now, they have been mainly investigated by drilling from the surface into the wells net to dictate the legal regulations. Due to the increase in depths on which deposits are located and complex structural relationships, such research has become more and less effective. From the geological point of view, the bauxite deposits are in the horizontal position. But long-lasting geological evolution from the upper Cretaceous to the present, has led to deposits in very different structural positions. That is why we find them in a tilted position, in subvertical and vertical, and often in an inverse position. For further research to become rational and efficient, a new approach to exploring basement from underground mining works will be developed that will serve for exploration and then for the exploitation of bauxite deposits

THE WATER-SUPPLY POSSIBILITIES IN THE REGION OF USORA

U aluviju rijeke Usore razvijen je kvartarni šljunkoviti vodonosnik iz kojega je moguće pridobiti potrebite količine vode za vodoopskrbu područja Usore. To je plitki otvoreni vodonosnik visoke propusnosti. Debljina mu doseže do 4,5 m. Leži diskordantno preko pliocenskih glina. Krovina šljunčanog sloja je tanka, slabo propusna, a ponegdje nedostaje. Vodonosnik je u neposrednoj hidrauličkoj svezi s rijekom Usorom i pri niskim vodostajima debljina vodonosnika toliko opadne da bi izdašnost budućih zdenaca snažno ovisila o prilagodbi zahvata uvjetima pri minimalnim vodostajima. U takvim okolnostima posebnu važnost treba posvetiti kritičnim veličinama toka. a posebice kritičnoj visini toka iznad nepropusne podine, te izboru i načinu polaganja zdenačkih sita, i prostornom odnosu zdenaca, strukture podine i korita rijeke Usore. Polučeni rezultati ukazuju da je moguća izdašnost zdenaca pri minimalnim vodostajima u rasponu od 5 do 10 l/s. a to je značajan iznos u potrebama vodoopskrbe.Gravelly Alluvial aquifer of Usora river is developed suitable for water-supply management Of the Usora region. It is a shallow uncon-fined aquifer of high conductivity. Its thickness reaches up to 4.5 meters, unconformably overlying Pliocene clays. The cover above this gravel-dominated layer is thin, partly permeable or completely missing. The aquifer is in fairly good hydraulic continuity with Usora river flow. Capacity of planned wells will lie directly dependent on the well-site positioning to optimal hydrogcoiogical conditions, well-construction modifications to critical flow values for the minimal water level periods, and particularly, on well screen-type selection and construction. Results obtained so far confirm the potential well capacity within range of 5 to 10 l/s

Stratigraphy of Paleogene Strata within the Mesihovina - Rakitno Area (Western Herzegovina)

The paper presents the stratigraphy of Paleogene strata from the central part of carbonate Dinarides. The carbonate and the clastic rock units were studied. Their contact with underlying Senonian lime stone is marked by unconformity as a result of Laramian tectonic phase.The unconformity is denoted by the abundance of bauxite deposits.The abundance of calcareous nanoplancton species as well asben tic foraminifera points at the sedimentation of Paleogene strata during the Eocene period. The succession of sediments with easily recognizable transgressive, inundation and regres sive features has been established. Lithostratigraphical characteristics enabled the distinguishing of larger lithofacies groups. The simultaneousness of carbonate rocks with lower part of clastic succession as well as the transitionallitho·facies have been approved. The simultaneous overburden of bauxite deposits regardless of its lithology (carbonate of clastic) speaks in favour of the unite bauxite bearing phase