Structural control on the kinematics of the deep-seated La Clapière landslide revealed by L-band InSAR observations

The objective of this work is to document the deformation pattern of the deep-seated La Clapière landslide for the period 2007–2010 from the combination of L-band synthetic aperture radar (SAR) interferograms, ground-based total station measurements and identification of the slope geomorphological structures. The interferograms are calculated for pairs of ALOS/PALSAR images at a time interval of 46 days. The displacement field derived from the interferograms reveals a non-uniform displacement gradient from the top (subsidence) to the bottom (accumulation). Vertical velocities are calculated from the unwrapped phase values and are in good agreement with ground-based measurements. The results demonstrate the potential of L-band ALOS/PALSAR imagery for the monitoring of active landslides characterized by complex kinematic patterns and by important changes in the soil surface backscattering in time.     

Optimizing Ore–Waste Dig-Limits as Part of Operational Mine Planning Through Genetic Algorithms

Dig-limit optimization is an operational decision making problem that significantly affects the value of open-pit mining operations. Traditionally, dig-limits have been drawn by hand and can be defined as classifying practical ore and waste boundaries suiting equipment sizes in a bench. In this paper, an optimization approach based on a genetic algorithm (GA) was developed to approximate optimal dig-limits on a bench, given grade control data, equipment constraints, processing, and mining costs. A case study was conducted on a sample disseminated nickel bench, in a two destination and single ore-type deposit. The results from using the GA are compared to hand-drawn results. The study shows that GA-based approach can be effectively used for dig-limit optimization.     

The impact of salt on the late Messinian to recent tectonostratigraphic evolution of the Cyprus subduction zone

Messinian evaporites of locally more than 3‐km thickness occupy the subduction zone between Cyprus and Eratosthenes Seamount. Based on a dense grid of seismic reflection profiles, we report on compressional salt tectonics and its impact on the Late Miocene to Quaternary structural evolution of the Cyprus subduction zone. Results show that evaporites have experienced significant post‐Messinian shortening along the plate boundary. Shortening has initiated allochthonous salt advance between Cyprus and Eratosthenes Seamount, representing an excellent example of salt which efficiently escapes subduction and accretion. Further east, between Eratosthenes Seamount and the Hecataeus Rise, evaporites were compressionally inflated without having advanced across post‐Messinian strata. Such differences in the magnitude of salt tectonic shortening may reflect a predominately north–south oriented post‐Messinian convergence direction, raising the possibility of a later coupling between the motion of Cyprus and Anatolia than previously thought. Along the area bordered by Cyprus and Eratosthenes Seamount a prominent step in the seafloor represents the northern boundary of a controversially debated semi‐circular depression. Coinciding with the southern edge of the salt sheet, this bathymetric feature is suggested to have formed as a consequence of compressional salt inflation and seamount‐directed salt advance. Topographic lows on top of highly deformed evaporites are locally filled by up to 700 m of late Messinian sediments. The uppermost 200 m of these sediments were drilled in the course of ODP Leg 160 and interpreted to represent Lago Mare‐type deposits (Robertson, Tectonophysics, 1998d, 298 , 63‐82). Lago Mare deposits are spatially restricted to the western part of the subduction zone, pinching out towards the east whereas presumably continuing into the Herodotus Basin further west. We suggest a sea level control on late Messinian Lago Mare sedimentation, facilitating sediment delivery into basinal areas whereas inhibiting Lago Mare deposition into the desiccated Levant Basin. Locally, early salt deformation is believed to have provided additional accommodation space for Lago Mare sedimentation, resulting in the presently observed minibasin‐like geometry.