Mirna Aparecida Neves

Qualidade da água em microbacias hidrográficas com diferentes coberturas do solo no sul do Espírito Santo

The objective of this work was to evaluate the quality of surface water and groundwater in watersheds characterized by different vegetal cover: pasture, forest and coffee crops. It was developed a water quality index by using the analysis of the main components, which provided the reduction of 13 quality features into two components that explained 91.2% of the total variance. Surface water and groundwater of the watersheds were suitable for human consumption after conventional treatment over the studied period, except the groundwater of watershed covered with pasture in the dry season.

Structural control over well productivity in the Jundiaí River Catchment, Southeastern Brazil

The well productivity in crystalline terrains is extremely changeable and depends on external factors, in addition to the intrinsic properties of rocks. In the Jundiaí River Catchment, Southeastern Brazil, the main factor that influences well productivity is the existence of open discontinuities permeability in geologic environments that favor groundwater recharge. In that area, Pre-Cambrian shear and fault zones were reactivated throughout geologic time, controlling the morphostructural compartments and the Cenozoic sedimentary deposition. Superposition of productivity data and structural maps showed that more productive wells are concentrated mainly along the regional geologic structures. The structural control over well productivity is also noticeable in detailed scale. Using fine scale maps we show that the most productive wells are located in areas where brittle structures with NW-SE and E-W directions denote the action of neotectonic transtensional stress. The comprehension of evolutionary geologic history allied to fracturing analysis proved to be an efficient and a low cost technique, which is adequate for selecting areas for further developments using more expensive methods.

Resíduos de serragem de mármores como corretivo da acidez de solo

The great volume of calcareous wastes generated by dimension stone industry and its composition, rich in important elements to promote plant growth, indicate possibilities of utilizing them as amendment of soil acidity. This study aimed to compare the capacity of neutralization of soil acidity and the use of two kinds of marble waste and a commercial limestone. The experiment was conducted in a completely randomized design, in factorial scheme, with four replications. An Oxisol mixed with four different doses of amendment (75, 100, 150, 300% and control), based on a standard recommendation. The experimental units consited of storage in polyethylene bags, and the soil moisture was elevated up to 70% of field capacity using distillated water. The pH, Ca, Mg, Al, H + Al, were analysed and SB, CTC, V were calculated. The wastes showed good potential to be used as amendment of soil acidity, since the initial reactivity was higher than the commercial limestone.

pH e umidade dos resíduos finos de beneficiamento de rochas ornamentais

The aim of this work was to analyze pH and humidity variations of fine wastes from processing dimension stones. Samples were collected during block cutting; plate polishing; after filter press and at deposits of different ages, including a temporary deposit 3 months old, a deposit of wastes 5 years old and another 20 years old. The pH and humidity were measured according to NBR 10.004/2004 and NBR 10.006/2004. Regarding pH values, wastes are not classified as dangerous in any case. Such parameter decays with time, even at inadequate storing conditions. This research showed that the use of a filter press decreases the pH and humidity of wastes according to regulatory requirements and the same results can be reached using correctly built pond drying. Humidity problems were found in the ancient deposit, where values increased at depth, reaching levels similar to newly generated wastes even after 20 year of storing. These wastes are located at alluvial plain, near a drainage channel.

Use of Fine Wastes from Dimension Stone Industry in the Manufacture of Ceramic Tile

Large quantities of rock dust are daily discarded by dimension stone industries. These wastes can be reduced if they are selected according to their composition and used as base in other products. Two kinds of wastes (BS and OI) were mixed at different proportions with kaolinitic clay traditionally used as raw material in ceramic industry. BS has high contents of plagioclase, quartz, microcline and low biotitic; and OI has high quantities of microcline and plagioclase, besides quartz, biotitic, enstatite and edenite. At the same firing temperature, water absorption of samples with 50% BS, or less, didnt show significant differences in relation to samples with pure clay, but firing shrinkage and flexural strength decreased. On the other hand, mixtures with OI content up to 50% showed reduction of water absorption and firing shrinkage, while flexural strength was increased.

Classification and Use of Fine Wastes from Dimension Stone Industry

Brazil is one of the main producers of dimension stones in the world and most of its production is for international market. Cutting granites and marble blocks to produce plates, and polishing theses plates, generate a fine waste whose characteristics indicate possibilities to be used in other products, such as ceramic material. The residue, also known as abrasive slurry, can cause environmental damage depending on chemical composition. The proper treatment, storage and application of this material ask for studies about their composition and transformations along time. The aim of this work is to analyze five deposits of dimension stone wastes with different ages and stored under different conditions. Residues have high compositional variability, but none showed elements content that could be considered dangerous to the environment.