Sampling Techniques for the Characterization of Hub River Aggregates, Sindh Balochistan Area, Pakistan

摘要

Hub River Basin forms a dividing line between Sindh and Balochistan Province of Pakistan. The studied area forms a 60km stretch of Hub river bed deposits trending in northwest and southeast direction and hosts the major quarries and crushers supplying aggregates for construction work in the metropolis city of Karachi. The stream bed deposits of sub recent to recent in age comprises of gravels, pebbles and boulders. The studied area has been divided into upper middle and lower zones on the basis of variation in the material sizes and physical properties. GPS was utilized to locate quarries and crushers and a Hub river aggregate resource map has been produced for the first time. The estimated monthly production of crushed rocks from the quarries in the area is about 18 million cuft. Experimental design for the sampling of aggregates is based on the initial field data and observations as well as on literature review. The emerged scenario dictated that in order to cover the base properties of the aggregates at source as well their resulting properties as crushed rocks, the effect of color, shape and conditions must be incorporated in all the detailed sampling and the testing programs. This formed the basis of a two prong direction for the design of experiment; namely, probabilistic based experiment design that provided the minimum sample size attached with a given probability and ANOVA approach that provided the statistical significance of the obtained sample size. This paper presents the sampling techniques used for the characterization of Aggregates from Hub River basin area and produces the aggregate resource map; first of its kind for the studied area.