In transitional mineralization, the sill of the underlying variogram is relatively easily estimated, but the estimation of the nugget effect may be more difficult. This study aims to determine for massive copper deposits just how sensitive the estimations of ore reserve, economic copper content, total net value, and ultimate pit limits are to the errors of estimation in the nugget effect of the spherical variogram model. A massive copper deposit which has a log-normal distribution and a spherical variogram was simulated on a rectangular grid using the turning bands method. By using the three-dimensional random kriging method, the mean block grades were estimated at four different sampling densities. The ultimate pit-limits were determined by using the two-dimensional dynamic programming algorithm. To calculate the estimation errors, the values obtained by using the actual nugget effect and structured component values were deducted from the estimations obtained using the incorrect nugget effect and structured component values. For isotropic massive copper deposits, it was found that the ratio of the nugget effect to the structured component of the spherical variogram has no significant effect on either the block grades estimated by the kriging method or on the ultimate pit limits.


The Effect of Calcined Colemanite Addition on the Mechanical Strength of Magnetite Pellets Produced with Organic Binders
SİVRİKAYA, OSMAN; Arol, Ali İhsan; Eisele, Timothy; Kawatra, S. Komar (2013-06-01)
Iron ore pellets must have sufficient mechanical strengths against degradation in all stages of pellet production. Low strength is also a problem for product pellets since they abrade during transportation to the reduction furnaces. The use of a binder is necessary to provide sufficient strength to the pellets and for better operation and handling of pellets. Bentonite is the standard binder in the industry; however, it is considered an impurity due to its acid oxide contents. Organic binders have been test...
The effect of strain rate and temperature on deep drawing for different constitutive relations
Gökşen, Seçkin; Darendeliler, Haluk; Department of Mechanical Engineering (2019)
In this study, the effects of strain rate and temperature on deep drawing process are investigated by considering different yield criteria and hardening models. For this purpose, various punch velocity and temperature values are considered using 1 mmthick DKP6112 and AZ31 sheet materials. The results are compared according to thickness strain distribution and punch force obtained by a commercial finite element software. To express constitutive relations of corresponding materials for different strain rate a...
The Role of Electrostatic Interaction between Free Charge Carriers and Counterions in Thermoelectric Power Factor of Conducting Polymers: From Crystalline to Polycrystalline Domains
Shi, Wen; Yıldırım, Erol; Wu, Gang; Wong, Zicong Marvin; Deng, Tianqi; Wang, Jian-Sheng; Xu, Jianwei; Yang, Shuo-Wang (2020-06-01)
One of the most burning problems in organic thermoelectrics is the lack of deep understanding on the key limiting factors of thermoelectric efficiency at different length scales for conducting polymers. Here, by examining a prototypical pi-conjugated polymer, poly(3-hexylthiophene) from molecular level to crystalline and polycrystalline domains, and on the basis of first-principles calculations, new insights are presented into the thermoelectric transport in conducting polymers, and new material design guid...
The effect of different solvents on the performance of zeolite-filled composite pervaporation membranes
Sener, Tansel; Okumus, Emin; Gurkan, Turker; Yılmaz, Levent (2010-10-15)
The aim of this research is to study effect of different solvents on the membrane morphology and on the performance of zeolite-filled composite pervaporation membranes. PAN (polyacrylonitrile) was used as a base polymer and zeolite 13x (32 wt.%) was used as the filler. The solvents considered were DMF (dimethyl formamide), DMSO (dimethyl sulfoxide), DMAc (dimethyl acedamide) and THF (tetrahydrofuran). The cross-sectional morphology of manufactured membranes shows three layers: a zeolite-free polymer layer, ...
The stable isotope composition of waters of the eastern Mediterranean Sea
Gat, JR; Shemesh, A; Tziperman, E; Hecht, A; Georgopoulos, D; Basturk, O (1996-03-15)
Waters of the eastern Mediterranean portray an unusual pattern of stable isotope composition compared with other evaporitic systems: an increase in O-18 concentration up to value of delta(18)O = +2.2 parts per thousand is not matched by a commensurate increase of deuterium. It is shown that this unusual pattern is an expression of the ''medi-terranean'' location of the sea, where the air-sea interaction with relatively dry and isotopically depleted continental air masses dominates the evaporation process in...
Citation Formats
E. YALCIN and A. UNAL, “THE EFFECT OF THE VARIOGRAM ESTIMATION ON PIT-LIMIT DESIGN,” CIM BULLETIN, pp. 47–50, 1992, Accessed: 00, 2020. [Online]. Available: