m.r. akbarzadeh

Loading and hauling operations have the highest share of the production costs of open-pit mines. Therefore, in choosing the loading and hauling machines, paying attention to the economic aspects is necessary. For a better understanding of the financial performance of mining machinery, various performance indicators have been proposed by researchers. This research presents a special form of economic performance index, which indicates the ratio of each machine's revenue to its total cost. For this purpose, the cost and revenue of the transport fleet, including dump trucks, mining shovels, and backhoe excavators, were collected for two years (From September 2017 to September 2019) and determined. As the first step, the total cost and the amount of revenue from the operation of each machine then, the Economic Performance Index (EPI) for each of the loading and hauling machines is calculated and compared with each other. The results show that Backhoe excavators perform better than mining shovels. In addition, by examining different trucks from different manufacturers, it was found that C100 series trucks have the best performance among all trucks. Its average economic performance index value for each of those trucks is 2.82.

Soil erosion and surface runoff generation is a serious environmental threat to sustainable development and agriculture, that may lead to a reduced soil fertility, nutrient loss, and reduced plant performance in the agricultural areas. In recent years, the use of modeling is introduced as a means to evaluate the impact of erosion reduction measures. SWAT is a conceptual and distribution model developed to predict and estimate surface runoff, sediment brought, qualitative characteristics of water, as well as to predict the effects of different management measures in the basin. The aim of this study was to investigate the usefulness of SWAT model to estimate the average daily flow rate and calibrate and validate the model in Atrak watershed at Khorasan Razavi North Khorasan provinces. Calibration and uncertainty analysis of the model were performed using SUFI-2. Indicators P-factor, R-factor, br2, and r2 were used in order to assess the ability of SWAT model to simulate Atrak watershed runoff. Runoff data of six hydrometric stations in 1975-1991 were used for calibration and validation of this basin. The results showed that the monthly runoff at calibration stage, the coefficients P-factor, R-factor, br2, and r2 in output basin was 0.73, 1.15, 0.53, and 0.56, and in the validation stage was 0.77, 1.3, 0.48 and 0.58, respectively. The best results were obtained in Shirabad station and the weakest results in Gharehkahnbandi station. Overall calibration results show that the SWAT model can be a useful tool in river flow rate simulation.