Purpose. Although the hydrocyclone separator has many advantages, it still has some limitations which decrease its separation efficiency in many mineral processing applications because of fine particles which are miss separated to the coarse product in the underflow. Water injection in the conical part of the cyclone was recently implemented to solve this problem. The water injection mechanism and the way in which the injected water affects the separation are still not clear and need to be more investigated. Methods. New design of water injection hydrocyclone was tried using a modified conical part with a water injection range consist of five equal distance injection openings open directly on the periphery of the cone part. Findings. This study presents a mechanical mathematical model that simulates the water injection to give a clear indication of the injection mechanism impact on the classification process. It could also predict the dependence of the basic characteristics of the classification on the amount of the injected water and the influence of different operating and design parameters of the hydrocyclone. Originality. The model accounts for the fluid flow, the particle motion, the turbulent particle diffusion, and particle settling. Particle interactions and fine particle entrainment by settling coarse particles are also included in the model. The model was found to predict well the injection effect and agrees with the experimental results. Practical implications. The results showed also that the increase in water injection velocity leads to an increase in both the cut size and the minimal value of the separation curve. It was found also that the hydrocyclone length has an important effect on the injection process, and the separation sharpness is directly proportional to it at higher values of water injection velocity.

Purpose. In recent years in Egypt there has been a significant increase in the demand for building materials, particularly gravel which is employed in buildings, the base layer for road construction, and other industries. The quality of gravel that is deemed suitable for different purposes depends on the physical, chemical, and mechanical properties of the gravel; these aspects are determined according to the Egyptian Code, depending on the required application. Methods. Representative samples were collected from two working sides of the quarries, then they were processed in a laboratory to characterize the samples depending on the location and evaluate their properties with respect to the corresponding concrete and road codes. Findings. The findings indicate that the gravel tests were simple to conduct and that the gravel from these locations were suitable for constructed roads and to be used in mixture of asphalt and cement. Originality. The samples were collected from five quarries around the Qena Governorate, Egypt; each of these locations occupied areas ranging from approximately 100×100 or 200×100 m2. Practical implications. The loss of gravel at the studied quarries was found to be 32.88-44.06%. Abo-Teshet 1 exhibited the highest loss of gravel deposits with thicknesses ranging from 0.5 to 1.50 m, which was attributed to the fill layers.

Purpose. The purpose of this research is to investigate the effect of weight on bit (WOB), rotary speed (RPM), and some rock properties on the rate of penetration (ROP). Methods. Four types of rock were collected from different sites in the south of Egypt (Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble). These tested samples were drilled by diamond core bit using a fixed laboratory diamond drilling machine under conditions (400 and 1200 rpm), and loads from 12 to 220 kg. WOB, ROP, torque (T) and specific energy (SE) were continuously observed during the drilling trials. The effect of these factors on ROP were examined. Water is used as a flushing and cooling medium. Findings. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate. Originality. The effect of some operation factors on the penetration rate regarding mineral composition and different rock type was evaluated and the general equation was carried out to predict the suitable operation factor which gives the best penetration Rate. Practical implications. The Results demonstrated that ROP was inversely proportional to compressive strength (CS), tensile strength (TS), and density. It was also found that Aswan sandstone, Isawya limestone, Assiut limestone, and Minya marble have CS 111.94 MPa, 131.22 MPa, 125.0 MPa, and 502.5 MPa respectively. Was established that ROP was directly proportional to porosity. Increasing ROP in case of Aswan sandstone is associated with increase in porosity – 23.158%, and in case of Assiut limestone and Isawya limestone ROP is also associated with an increase in porosity – 19.9% and 17.93% respectively. Decreasing ROP in case of Minya marble is associated with decrease in porosity – 2.314%. So, we concluded that marble has lower ROP due to its higher CS, TS, and density and lower porosity than other tested rocks.

Purpose. The economic value of phosphate is reduced when randomly blending raw phosphate produced from different mines. Therefore, the blending process of different raw phosphate ores to produce economic percentage of P2O5 is essential to maximize the profit of a mine as regards suitable mine design. Methods. This paper presents an application of Linear programming (LP) method to determine the optimum quantities of phosphate ore needed per each mine for blending process. Three phosphate operations, located in Aswan pro-vince south of Egypt, have been chosen for this study namely B1, B2 and C. Findings. The results of LP methods reveal that the phosphate ore of 24% of P2O5 will be produced by blending 16.8% of phosphate ore from operation B1, 9.42% of phosphate ore from operation B2 and 73.78% of phosphate ore from operation C. Whilst the phosphate ore of 22% P2O5 will only be obtained by blending 66.43% of phosphate ore from operation B1 and 33.57% from mine B2. Originality. Estimating the suitable height of benches according to stability, safety of work place and efficiency of work place. The suitable height of benches was found according to the efficiency of work place ranged from 12 m to 30 m. Sub benches were divided to keep the assays of the phosphate ores from dilution and the result is that the height of sub bench for overburden ranged from 7 m to 11 m, for the third layer from 0.2 m to 0.3 m, for the upper layer from 0.4 m to 0.6 m and for the lower layer from 0.3 m to 1 m. Practical implications. Applied linear programming in mining as regard mining operations to obtain the optimum solution in mining sites.

Purpose. The main purpose is solving transportation problems using some methods of transportation modeling by linear programming. Linear programming has already demonstrated its value as an aid to making decisions in mining, business, industry, and governmental applications. This paper discusses how to solve transportation problems using manual solution method and computer software solutions. The transportation model deals with a special case of linear programming problems whose objective is to “transport” a single commodity from various “points of departure” to different “destinations” at minimum total cost. Methods. In this paper, we used manual and computer software to solve many problems in mining engineering. Findings. The optimum solution for the problems occurring in the mine site, which will apply for future problems in different conditions, has been obtained. It was proved that results are identical because they produce the same effect when solving the problem using the following five methods: northwest corner method; minimum cost method; row minimum cost method; column minimum cost method, and Vogel’s approximation method. Originality. The new trend is how to use computer application in solving all mining problems and obtain the optimum solution for any problem considering the constraints. Practical implications. All the suggested solutions are optimum ways to solve mining problems which can be applied to any problem beyond the studied field.