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

Infrastructures such as road, building, cannals, dam, bridges and so on lie on geological bases. Durability of the structures demands detail study of rocks in microscopic level. Such study helps to give knowledge about strength and physical properties of rocks, and their usefulness as construction materials. Index properties are the basic parameters to be found out before the developent of engineering structures, and are governed by the texture of the rock such as grain interlocking, crystallinity, shape factor, grain size homogeneity, grain orientation, micro fractures, etc.Textural study of the samples gave the micropetrographic quality index ranging from 0.05 to 49, grain size homogeneity from 0.06 to 0.74, interlocking index ranging from 7 to 92% and texture coefficient ranging from 1.08-1.97. Micropetrographic index has great influence on porosity and point load strength index. Siliceous rocks having high texture coefficient are mechanically sound. When homogeneity in grain size, shape and orientation increases, texture coefficient tends to diminish. Therefore, texture coefficient is an important variable.Dry density of samples ranges from 2309 to 3224 kg/m3, porosity from 0.08 to 8.91% and point load index from 0.26 to 13.13 MPa. Water Absorption Value (WAV) is entirely below 2% except for the slates indicating that most of the rocks have low effective porosity. Strength of rocks varies from very low to very high. Considering the texture and index properties, the rock types suggested for the construction aggregates are quartzites of the Nourpul Formation, the Fagfog Quartzite, and the Chisapani Quartzite, and psammitic schist of the Robang Formation. The quartzite samples from the Fagfog and the Norpul Formations are useful for silica sources. Siliceous dolomite ‘Np3’ of the Nourpul Formation and dolomite ‘Ml1’ of the Malekhu Limestone also show good interlocking, high density and high strength.Bulletin of the Department of Geology Vol. 18, 2015, pp. 1–14