نشریه زمین شناسی محیط زیست
پیاپی 11 (تابستان 1389)

Environmental problems of heavy metals are especially important. For sustainable development of mining industry environmental aspects need to be identified it. The purpose of this research is study of gold genesis and accompanying elements in Siah Jangal region in Sistan and Baluchestan province with attention to contaminating elements of the environment. The study area near the sarkahnow village located in north volcano Taftan in South East of Iran in 120 km south East of Zahedan in Sistan and Baluchistan province In geological prospect, the exploratory region of Siah Jangal – Sarkahnow is located in filishi zone of east of Iran and the adjacent of one of the active tectonomagmatic centers of Iran. This area includes filish sediments and ophiolitic rocks with Upper Cretaceous age and Paleocene، which between Afghan (Helmand) and Lut block is located. In order To evaluate the contamination of heavy metals in the region as a systematic sampling was performed. After preparation of the samples were analysed. Theresults were compared with World Health Organization standards and were determined that the elements Cd, Pb, Ni, As contamination in the area and fortunately Hg element does not create a lot of contamination. With using this results were depicted the zonation maps of contamination of elements including As, Pb, Ni, Hg, Cd in this region and was delineate that these elements caused to contamination in this region. The maps showed that the mentioned elements are causing contamination of the area.

The mine area is located in 65km north of Kashmar(Khorasan-e-Razavi province-East Iran) and it forms a part of northeast of Central Iran zone. This area consists of Paleogene terrigenous sediments containing of shale, marl, sandstone and conglomerate with interlayers of pyroclastic rocks that age of sediments are belonged to Eocene. The faults with East-West trendin (parallel with Doruneh main fault) influenced the region and the formation of this deposit. The mineralogy of deposit is simple and consists of quartz, calcite, stibnite, pyrite, gold, realgar and orpiment. The main type alternations are arjillic, sericitic, pyritization, silicification and carbonatization. Field observations, petrography and paragenetic sequences indicate that mineralization is happened in epithermal vein system.

Heap leaching structures use for accumulate and obtaining metals from ore. These structures compose of different parts. Among those, creating a drainage layer in the mineral material bed is very important. because during this long period the amount, of the permeability will decrease, due to different factors. In addition to these factors, we also mention to the chemical, physical and biological factors. The author is trying to examine the effect of chemical factors on heap leaching structures drainage gravel, by simulating different parts of the leaching structures. Therefore, suitable cells are built for accumulating ore materials and drainage gravel. After filling these cells with the before said material during 6 months, acid is been irrigation on ore material cells and the cell output is transferred to the input of the drainage gravel cells. The permanent washing of the ore material and the action and reaction, cause a chemical clogging and also the closing of the pores of the drainage gravel. In the determined period for simulation, the permeability amount of drainage gravel will be measured and the reduction amount of the coefficient of the permeability by the effect of clogging will be studied permanently. Suitable design for gravel drainage height, needs suitable information of the amount of permeability reduction. Use the obtained results of the simulation, due to the prevent of creating drainage damages.

Nowadays, the longwall mining method is one of the most usage methods in coal mining. Estimating of periodic roof weighting interval in longwall methods is one of the most important parameters in safety and success of coal mines production. Because, selecting of a lengths less than real size can hazard the miners’ life by electing a weak support system and also selecting the lengths more than real size constrain further costs to mine. In other hand, discontinuities of roof have negative effects to stability of immediate roof. In this research, equation between periodic roof weighting interval and GSI variations is extracted by numerical modeling. To evaluating this equation, the roof weighting interval of ten coal mines of India is considered. The results show that, the roof weighting interval of India’s coal mines and the results of this equation are properly same together.

The most important problem in tunneling project about design and performance is selection suitable pattern for drilling and support system, in order to stability of rock mass and reduction plasticity zone. Meanwhile determine the amount of tunnel wall deformation prior to support installation is of great importance. When a tunnel is excavated, there is a certain amount of deformation, usually 35-45 percent of the final tunnel wall deformation, before the support can be installed. Determining this deformation can be done using either a) observed field values, or b) numerically from 3D finite-element models or symmetrical finite-element models, or c) by use of empirical relationships such as those proposed by Panet or Vlachopoulos Diederichs. In this paper, convergence-confinement method is applied to tracing ground characteristic curve using numerical software models and then stress relaxation is exerted to modal that equivalent with occurred critical convergence until prior to support installation. In this study, a new chart is introduced which unlike conventional charts, the modulus reduction flow has been used in that vertical axis. Finally the safety factor of support system has been calculated by three different methods.

Hasansalaran granitoid is located in structural Sanandaj–Sirjan zone. This granitoid share tow parts: a) northern part, b) southern part, northern part is composed of biotite and hornbland granite, granodiorite and tonalite. In this Granitoid, ther are microgranular enclaves that are composed of quartzdiorite and tonalite and they have circular or ellipsoidal shapes. These rocks have granular, porphyritic and graphic texture and secondary textures are kataclastic and milonitic texture. Southern part composed of alkali feldspar granite, alkali syenite and quartz syenite that they have show granular matrix and pertite. The northern parts of Hasansalaran granitoid share all the geochemical features common to I – type granites. these granites are related with active continental margin zone. Southern parts are A – type and related with rifts. According to isotopic study Southern parts are older than Northern parts. Variation of major and trace elements shows magmatic differentiation, somewhat crustal contamination in northern part of studies area.

Nain ophiolites,which are part of Ophiolitic suite of western margin of Central Iran micro continent, covering 500 km2 crop out along Nain-Baft fault. The age of the emplacement of the ophiolitic suite is upper cretaceous and early paleocene based on microfossils found in pelagic limestones[1]. Diabasic dikes have been divided into microgabbro-gabbros, gabbros with hydrothermal metamorphism, rodingites, and amphibolites, based on hydrothermal metamorphism, metasomatism, and tectonic events that they have gone through[2]. These rocks have tholeit character in geochemical diagram(AFM), and the chondrite normalized spider diagrams shows enrichment in LREE and HREE. This enrichment is attributed to its differentiated origin. Geochemistry of trace elements and REE of these rocks and low(La/Y)N<1.5 and (La/Sm)N<1.5 ratios are similar to those of N-Morb to T- Morbin upper cretaceous.

Garmsar and Eyvanekey plans are located south of central Alborz, between north central Iran, and to connect mountains with basins. the existence of alluvials of arise from Alborz mountion erosion created aquifers, geological investigation firm that evaporates and salt dooms of upper and lower red formation cause of increase salinity and thus sulfat solution in alluviu, this subject effect in increased porosity of sediments. Measurement of piezometric wells show ground water drawdown in the last 18 years, and this subject on the basic of procedure exploitation in the 30 years is similar. Calculations based drawdown at least 27 meters of ground water table caused about 50 60 cm subsidence, and 20-30 cm. subsidence due 20 years at next. Calculation ground water depletion produce surface cracks, deep fractures anddamage buil ings. It necessary attention to water management and geological engineering specifications in contracture project at future