Iraq is one of the most affected countries in the Middle East concerning the occurrences of sand and dust storms. The frequency of the occurrence has increased drastically in the last decade and it is increasing continuously. The events of sand and dust storms are either regional or local. The former, however, is more frequent than the latter. The regional event, generally extends outside the Iraqi territory, into different directions, but usually covers part of Syria, crossing the Iraqi territory towards Kuwait and Saudi Arabia, and/or towards the Arabian Gulf, and less frequently extends to Iran. The main causes in the development of sand and dust storms, in Iraq are discussed. The causes are also either regional or local. The former, however, causes more economic losses and harsh effect on the human's health, as compared with the latter. One of the main reasons behind the development of sand and dust storms is the climatic changes within the region, especially the drastic decrease in the annual rate of rain fall, besides environmental changes, such as drying of the marshes, land degradation, and desertification. From the local causes, the most effective reason is the haphazard driving and military operations, especially in the Iraqi Southern Desert. Prudent management of water resources by using non-conventional resources and adapting suitable irrigation methods can greatly help to overcome this phenomenon and minimize the number of dust storm.
Tailings’ Dams are mining waste impounding structures. They differ from conventional dams in purpose, design and operation. Percentage wise their failures are higher and posing considerably more safety concerns, causing long lasting devastation on communities, environment, and animal and plant ecosystem. Two basic types of embankment tailings structures are used for tailings impoundments; the Retention Dams and the Raised Dams. Retention dams are built in one operation to a full height, while construction of Raised Dams is a continuous process lasting for the whole useful life of the mine. Raised Dams are favored over Retention dams as they can be enlarged and expanded as the extraction works continue with time. Raised embankment dams themselves can be of three alternative designs according to the method used in construction; the Downstream, Upstream and Centerline structures. This designates the direction in which the embankment crest moves in relation to the initial embankment at the base as successive lifts are added. Resulting from the used method of tailings weight disposition, the Upstream Raised Dams are the least safe in earthquake prone areas as compared to the other two types due to its higher possibility of liquefaction, so they are not favored in highly seismic areas. The disadvantage of Downstream Raised Dams is their use of larger land areas. Centerline Raised Dams are a compromise between the other two. Tailing Dams failure may occur due to: dam instability, overtopping, internal erosion, or combination of these. Instability can result from faulty design and/ or faulty tailings deposition method. Internal erosion can follow saturation of the fill due to fast rate of work and close proximity of the water pond to the dyke combined with downstream gullying, and overtopping happens in case of faulty water management and/ or inoperable decan system. Careful analysis of historic failures and drawing out new lessons from them can help reducing failure probability and enhance tailings’ dams’ safety.
The use of geophysical methods in dam sites investigations and safety monitory has proved their good value and versatility in many earthfill dam sites as early as the 1920s. In the following years great development has occurred in the methods, application procedures and tools used. They may be considered today as good ways for carrying out observation tasks on existing dams in non-intrusive and much faster and cheaper ways than the traditional geotechnical methods. It is possible using them to discover anomalies in the dam body or its foundation at an early stage and allowing quick intervention repair works. These methods seek to register and present variations in the basic geotechnical material properties in dams such as; bulk density, moisture content, elasticity, mechanical properties of rocks, electrical resistivity and mineralogy and magnetic properties and so forth. Such variations can indicate increasing seepage flow, progression in cracks’ sizes, formation of voids, caverns and other instability manifestations. Depending on how any investigation is carried out and the targeted anomaly, there is now selection of these methods such as: Electromagnetic Profiling (EM), Electrical Resistivity Tomography (ERT), SelfPotential (SP), Ground Penetration Radar (GPR), variety of Seismic Methods (SM) which can be applied using such equipment as in Seismic refraction, Seismic Reflection, Multi Analysis of Rayleigh surface waves (MASW) instruments, or using Refraction Micrometer (ReMi), macro-gravity method, and Cross-Hole Seismic Tomography. In addition, Temperature Measurements and other less used methods can be used like Microgravity measurement, Magnetic Profiling and Radio Magnetotelluric methods. An attempt is made here to cover the details of these methods, their advantages and limitations and to prove their usefulness in many dam sites all over the world. One observed issue is their adaptability to embankment dams more than to concrete dams and their popularity for checking seepage related problems and material changes within dam bodies and their foundations such as formation of voids and sinkholes.
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