Aggregate, the inert materials used in almost every field of modern development structures have great influence. Aggregates may look similar in appearance but they may carry different physical, mechanical and chemical properties and they may perform accordingly. End uses of aggregates are also determined by their performance. The Lesser Himalaya of the Malekhu- Thopal area comprises more than 14 formations having great potential of rock aggregates. The present study was carried out in order to reveal the toughness and soundness of each rock type of the Lesser Himalaya so that durability can be determined. Altogether 25 representative samples were tested to find porosity, specific gravity, dry density, uniaxial compressive strength (UCS), Los Angeles abrasion value (LAAV), aggregates impact value (AIV), sodium sulphate soundness Value (SSSV), ethylene glycol soaking value and water absorption value (WAV). Results were compared with standards of different specifications and recommended for wide range end uses.Rock mass rating of each formation was carried out and the value ranges from 36 to 82. Specific gravity ranges from 2.08 to 3.08 and the dry density ranges from 2.3 to 3.22 g/cm3. All the samples have porosity less than 2% except the samples of the Benighat Slate. UCS value ranges from 5.9 to 301.9 MPa. The LAAV of the sample lies between 19.6% and 47.5%. AIV is between 8.54% and 34.28%. The SSSV ranges from 2.35 to 26.06%. Ethylene glycol soak index is 2 of all samples signifying that proportion of swelling clays or low accessibility of ethylene glycol through the samples due to low porosity. WAV of all the samples is below 2% except the Benighat Slates which indicates that the aggregates have low effective porosity. The entire test shows that most of the sample meets different national and international standards and can be recommended for wide range of end uses.Bulletin of the Department of Geology, Vol. 18, 2015, pp. 15–34

A huge landslide was identified on the right bank of the Malekhu River at about 1 km upstream from the Malekhu Bridge of the Prithvi Highway, and was named Malekhu Landslide. The landslide area consists of quartzite with sericite partings, chlorite schist and amphibolite of the Robang Formation of the Kathmandu Complex. The landslide extends for about 200 m along the river bank slope and its crown and toe have elevation respectively of 429 m and 361 m a.s.l. The major portion of the hillslope has been altered by landsliding as evidenced from the different geometry of slopes consisting of very steep scarp slope, steep to moderate slope with toppled and wedge failure debris, and several wedges and gullies. The right-side up layers have an average dip direction of 167° and a plunge of 56-90°, whereas the overturned layers have an average dip direction and plunge of 316°/32°. The direction towards which the toppling had occurred is 167°. The overturned layers had rotated to 36°, during which the layer dip direction had rotated counterclockwise to an amount of 31° from the major direction of toppling, and this rotation should have occurred during sliding of the toppled block. The Malekhu Landslide is a complex landslide experiencing more than one mode of failure of which the most prominent one is the toppling. It is a kind of flexural toppling of passive mode and had already occurred and now is suspended. The second mode of failure is the wedge sliding. The kinematic analysis of discontinuities on the slope for evaluating possibility of landsliding has indicated that the wedge failure is potential due to the presence of a line of intersection produced by the discontinuity parallel to the foliation of the right-side up layers and the overturned layers. This suggests that the toppled blocks may further slide. It is required to protect the slope from landsliding as there have been extended two unpaved roads one along the crown and the other along the toe of the landslide, and due to existence of the Malekhu Bridge in the downstream stretch of the river. DOI: http://dx.doi.org/10.3126/bdg.v16i0.8881 Bulletin of the Department of Geology Vol. 16, 2013, pp. 21-28