52,493 research outputs found

    Optimization of blasting parameters in open cast quarries of El Hassa-Bouira (Northern Algeria)

    Get PDF
    In recent years, Algeria has known a rapid growth in the construction projects, such as: buildings, roads, and infrastructure, which increased the demand for aggregates production in quarries. However, vibrations and noises generated by blasting operations have a negative impact on the residents living nearby. For this reason, blast tests were performed in the open cast quarries of the company Sarl El Hassa-Bouira (Northern Algeria) using instantaneous electric detonators (IED), micro delays (MDD) and delays (EDD) to minimize the instantaneous load. We also minimized noise and vibration during the blasting. A seismograph allowed us to take further measurements

    The Geology as an indispensable tool for optimizing the exploration of dimension Stones

    Get PDF
    Like any Geological Resource, the Dimension Stones can only be exploited where they occur. How they occur is a reflection of geological history that presided over its formation. Their nature determines the mode of deposit and therefore it’s potential to be exploited as ornamental stone. The geological setting of the Portuguese marbles became a key factor in the optimization of its exploitation, two ductile deformation phases must be consider, which originates the complex folded metamorphic layering. At least three fracturing systems are responsible for the high segmentation of the marbles in fragile deformation conditions and that must also be considered. Together these geological constraints lead to a really low production ratio (3% - 12%). These low efficiency productions emphasized the emergence of the geological knowledge of individual quarries in order to optimize is exploitation. Until recent years, with high prices for the Portuguese marbles the companies haven’t been concerned with the geological knowledge of its quarries, but now that an economic crisis is installed in the sector, basic geological studies in the quarries are mandatory and could save thousands of euros for each company

    Conditioning Circuit Analysis for Slimes Management in Quarries

    Get PDF
    Driven by increasingly stringent environmental regulations on water usage, many European quarries are in the process of adding thickening circuits to their wash plants for managing clayey tailings. One of the critical components of this circuit is slurry conditioning. With typical water consumption over 1 m3 per ton of washed aggregates, quarries produce dilute streams that are conditioned with high flocculant dosages to maintain water clarification rates as high as possible. At present, conditioning systems used in the quarrying industry are designed from elementary rules-of-thumb derived from experience. Practitioners acknowledge that conditioning system design criteria should be investigated further in order to design more efficient full-scale conditioning systems. This work focuses on weir-based conditioning tanks used in European quarries. The paper presents an applied analysis of such conditioning systems based on a comparison between a full-scale conditioning circuit and a controlled laboratory conditioning set-up. Within the range of plant operating conditions, this approach shows that full-scale conditioning is essentially governed by average shear rate and conditioning time. However, fine floc size distribution measurements reveal that quarry slimes conditioning is a dynamic process. This explains the high sensitivity of the process to variations in hydrodynamics, and the challenges in industrial conditioning system design

    Quarrying and Sustainability during Urbanazion: Gebze District Case

    Get PDF
    The requirement of construction materials increases along with the developing urbanization. Despite the most of quarries are established in rural or semi rural areas, their locations remain in or close to the urban areas in parallel with the expansion of residential areas in proportion to the rate of urbanization. Continuing population growth, social, industrial and economic developments require more construction materials. Gebze region uses approximately 8,000,000 tons of aggregate per year for construction sector. The present quarries are planned to be abandoned in the following years. Regardless of potential problems, it is important for planning to estimate future recources. Nowadays there are public housing, organized industrial zones and highway projects at planning and construction stages. Nevertheless, Ballıkayalar National Park is close to likely potential material quarries. By avoiding the national park area, the availability and the quality of materials should be established at an early stage, as material production and transportation costs can be an important consideration when selecting a design solution.

    Proposals for environmental impact decreasing in a suburban zone of limestone quarries: Southem Madrid Community, Spain

    Get PDF
    Over 30 Mm3 of limestones are extracted at least 100 quarries in southem part ofMadrid, its environmental impact is described in this paper. Three main reclamation areas are distinguished: surrounding of quarries, faces or highwalls of quarries and the floor. For soil reclamation in the environs of quarries we suggest to sow it with forage of fast growth plants (Lupinus, Tripho/ium ... ), in the floor of quarries is possible a spontaneous revegetation or even may be reclaimed for agricultural uses. For quarried rocks faces previous blasting and/or wider benchs are proposed. In opinion of the authors it is necessary to concentrate the limestone extraction in two or three Iarge quarries that allows a best policy and reclamation

    Strength Calculations of Block Elements of Room-and-Pillar Mining under the Permafrost Conditions

    Get PDF
    The paper covers results of rheological properties of gypsum under natural conditions of permafrost and stress-and-strain conditions of room’s roof rocks in gypsum quarries depending upon the ceiling thickness. The recommendations concerning room and pillar parameters are given

    Notes on the Idea of a Species: A Look at Human/Neandertal Interbreeding

    Get PDF
    Unearthed within the limestone quarries that lie east of Dusseldorf in Germany, the first fossil to be recognized as an ancient hominin brought solid evidence to the table for starting to find answers to the question of where humans came from

    The building stones and slates of Killin : an investigation of stone for the built heritage

    Get PDF
    The village of Killin lies in an area of dramatic landscape and mountain scenery. The use of local stone in the buildings gives a direct connection to this landscape and reflects the local geology, comprising mostly metamorphic rocks of Precambrian age –dominantly limestone, meta-sandstone, mica schist and meta-igneous rocks. All of these (with the exception of the Loch Tay Limestone which was used for soil improvement) were used in buildings and structures within the Killin Conservation Area. The stone masonry in the village is classified into five categories; (1) cottages (mostly harled) built of random rubble from field and river boulders and surface rock outcrops, (2) two storey buildings with irregular coursed rubble walls of meta-sandstone and mica schist with large dressings of silver-grey slabs of actinolite schist, (3) and (4) larger late 19th century buildings with dressings of Central Belt sandstone used in combination with squared rubble walling of local actinolite schist and metasandstone. The 5th masonry category represents relatively late buildings constructed using distinctive imported stone types (e.g. whinstone, granite, red sandstone). These categories are broadly chronological in order and reflect the development of architectural form along with improving transportation of materials over time

    Fissures on the landscape: the sandstone quarries, traces of the heritage landscape of Mallorca

    Get PDF
    The sandstone quarries are the commonest quarries in Mallorca. However, they have been always unknown landscapes. This paper tries to offer a panoramic view of the sandstone quarries, tracking between different scales. First of all, the understanding of their territorial dimension on the island, proposing a new concept: the Quarries Territory, a landscape that allows the discovery of the quarries, only possible through the path that they offered, the differentiating aspect of each one. Afterwards, the memory and tradition that they have generated relate the elements of heritage which have emerged from them, so they are also part of cultural heritage and landscape of the island. They have become immobile transcribers of the landscape history that have generated, becoming true heritage archives of Mallorca. Finally, thinking in sandstone quarries as cultural landscapes will be obvious when the culture that generated them get back to appreciate the values described here. If this not happens, their future is predestined to disappear.Peer Reviewe
    corecore