کاربرد احتمالات هندسی در طراحی شبکه های اکتشاف کانسارهای معدنی، مطالعه موردی: اندیس مس پورفیری واقع در جنوب غرب کرمان

نوع مقاله: مقاله پژوهشی

نویسنده

دانشکده مهندسی معدن، دانشگاه صنعتی اراک

10.29252/anm.8.15.39

چکیده

در پژوهش حاضر مفاهیم نظری و کاربردی احتمالات هندسی، مورد بررسی قرار گرفته و روابط احتمالات هندسی برای تعیین احتمال تقاطع اشکال هندسی گوناگون با انواع شبکه­های مختلف، ارائه شده است. ازآنجایی­که پارامترهای هندسی کانسارهای معدنی دارای ماهیت احتمال­پذیر هستند، اکتشاف کانسارهای معدنی نیز ماهیت احتمال­پذیر داشته و همواره با عدم قطعیت و مقداری ریسک همراه است. در نتیجه از این نظر مسئله اکتشاف با مسائل احتمالات هندسی شباهت دارد. با توجه به روش­های متداول اکتشاف کانسارهای معدنی توسط شبکه­های اکتشافی مختلف و تشابه کانسارهای معدنی با اشکال هندسی معمول، نحوه طراحی شبکه اکتشاف بهینه برای هر نوع کانسار، براساس روابط موجود در احتمالات هندسی، ارائه شد. در این راستا به عنوان یک مطالعه میدانی طراحی شبکه اکتشاف بهینه با استفاده از احتمالات هندسی برای دو اندیس مس شناسایی شده با عملیات دورسنجی واقع در جنوب غرب کرمان یکی با ساختار تقریباً خطی و دیگری با ساختار تقریباً دایره‌ای، صورت گرفت. برای این منظور ابعاد شبکه اکتشاف بهینه برای هر اندیس با در نظر گرفتن کم‌ترین مقدار احتمال کشف یا 5/0 و احتمال کشف مطلوب یا 95/0 در دو حالت جهت­یافتگی تصادفی و با جهت­یافتگی مشخص، محاسبه شد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Application of geometric probability to design exploration grid of mineral deposits, case study: porphyry copper index located in the south-west of Kerman

نویسنده [English]

  • Reza Ahmadi
Dept. of Mining, Arak University of Technology
چکیده [English]

Summary
In present research, theoretical and applied concepts of geometric probability have been studied and the relationships of geometric probability have been presented to determine the probability of intersection of various geometric shapes with diverse types of grids. In this regard mineral deposits based on defining the shape ratio parameter as ratio of breadth to length of the deposit ( ) were classified to 3 types of linear, circular and elliptical shape. The detection of mineral deposit is possible under condition that the deposit is intersected at least once by the lines of exploration grid.
 
Introduction
Arrangement of accurate and optimum location of exploration works entitled designing of exploration grid is one of the essential requirements in all stages of mineral deposits exploration. Designing the optimum exploration grid is the most important as well as critical stage for exploration of mineral deposits. That is carried out on the basis of geological conditions and characteristics of deposit and the amount and type of available exploratory information. The type, shape, and dimensions of cells and orientation of the grid with respect to the estimated direction of the deposit, perform the geometry of exploration grid. Since the geometric parameters of mineral deposits are stochastic, exploration of mineral deposits is also stochastic and is always associated with uncertainty and some risk. As a result from this view point the exploration problem is similar to the geometric probability problems.
 
Methodology and Approaches
According to conventional exploration methods of mineral deposits by various exploration grids as well as similarity of mineral deposits with the usual geometric shapes, designing the optimum exploration grid for each type of deposit was presented based on existing relationships in geometric probability. In this context as a case study, designing the optimum exploration grid for two copper indices detected by remote sensing operation located in the south-west of Kerman, one with approximately linear structure (with a shape ratio of 0.14) and the other one with approximately circular shape, was carried out using the geometric probability.
 
Results and Conclusions
Due to the similarity of exploration of mineral deposits to geometric probability problems in this research, existing relationships in geometric probabilities were used to determine the probability of detection by the various exploration grids. By employing the mentioned approach, the size of optimum exploration grid was calculated for each index considering minimum exploration probability, 0.5 and favorite exploration probability, 0.95 for both randomly oriented and oriented situations.

کلیدواژه‌ها [English]

  • Geometric probability
  • Buffon’s needle problem
  • Optimum exploration grid
  • Exploration probability of mineral deposits
  • Porphyry copper index in the south-west of Kerman
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