Comparison of ore and tailings classification based on the results of ordinary erosion methods and local uniform conditioning

Document Type : Research Article

Authors

1 Master of Science in mineral processing engineering, Mine Design Supervisor, Miduk copper Complex

2 Associate professor, Mining Engineering Department, Kashan University

Abstract

Summary
In this research, the application of localized uniform conditioning (LUC) method for SMU classification into waste and ore based on 0.2% cutoff grade has been compared with the conventional estimation method in the Miduk copper mine. Based on the blast holes, for the two extraction panels. Finally, even assuming the same level of cost due to under-estimation and over-estimation, the LUC method is more desirable than Log-kriging.
 
Introduction
In the cases of the borehole data have large grid compared with the dimensions of the blocks, using the estimation techniques based on linear regression for modeling small blocks are. To solve this problem, Abzalov in 2006 introduced a new method of LUC which was result of a series of corrections on uniform conditioning (UC). In this method, after calculating the grade distribution functions for large panels, first, based on the uniform conditioning method, the large panel is divided into small blocks according to the increase of grade; small blocks located on the panels are ranked. This method is able to present the grade distribution functions for large panels based on UC method, and also can localized results of UC models.
 
Methodology and Approaches
In this research, we used Log-kriging and LUC techniques in order to classify waste and ore materials. The dimensions of the SMU units were chosen as 5×5×15 meters. Then, using Log-kriging and LUC methods the grade of each SMU blocks in the block model was estimated. Then, according to the 0.2% cutoff grade, the SMU was divided into waste and ore. The best way to compare these two methods is to compare them with the output of the ore control unit. According to the short distance between blast holes, the separation of the ore control unit was considered as real data. Based on this data obtained from the ore control unit, a block model was prepared and separation of waste and ore blocks was done. Then, the results of the separation based on the LUC, Log-kriging and blast hole model output were compared.
 
Results and Conclusions
Based on the blast holes, for the two extraction panels, 2450 and 2465, their results showed that the total blocks were separated to 4% waste and 96% of the ore; therefore, the ore percentage changes were considered for the conclusion. For the method of Log-kriging, in these two panels, 49% of the separation of the ore is matched with the ore control output, while in the 51% of the cases the ore was classified as waste. Also, according to the outputs of the LUC method, in these two benches, 98% of the classification of the ore was matched to the ore control output, and 2% of the separation of the ore was classified as waste. Therefore, even assuming the same level of cost due to under estimation and over estimation, the LUC method is more desirable.

Keywords

Main Subjects


 1- مقدمه

در زمین آمار، نامناسب بودن روش‌های تخمین بر پایه رگرسیون خطی در شرایطی که فاصله نمونه‌های عیاری در مقایسه با ابعاد بلوک تخمینی زیاد باشد، به عنوان یک اصل پذیرفته شده‌است [1-3]. کریجینگ معمولی (یکی از تخمینگرهای خطی) به عنوان یکی از روش‌های معمول تخمین ذخیره [4]، زمانی که فاصله بین نمونه‌ها نسبت به ابعاد بلوک زیاد باشد باعث نرم‌شدگی در گزارش خروجی ذخیره قابل استحصال می‌شود [1، 2، 5]. ماده معدنی که عیار آن بیش از عیار حد بوده و قابل استخراج باشد، به‌عنوان ذخیره قابل استحصال تعریف می‌شود [6]. دشوار ترین مرحله ارزیابی ذخیره، محاسبه ذخیره قابل استحصال براساس گمانه‌هایی با تعداد محدود و فاصله‌داری زیاد می‌باشد [7].

برای بررسی‌های فنی و اقتصادی در پروژه‌های معدنکاری بلوک‌های بزرگ تخمین زده شده (پلن‌ها) با فاصله‌داری زیاد داده‌های تعریف شده قابل اتکا نیست. زیرا نیاز به تخمین تناژ و عیار بخشی از کانی‌زایی واقع در واحد معدنکاری مورد نظر که به عنوان ماده‌معدنی شناخته شده است، دارد. در زمین‌ آمار، این فرآیند به عنوان تخمین ذخیره قابل استحصال در پایه v شناخته می‌شود که بلوک با ابعاد v بیانگر کوچکترین واحد معدنکاری انتخابی است (SMU) [8]. این روش تخمین، بدون استفاده از موقعیت مکانی، قسمتی از ذخیره که از لحاظ اقتصادی قابل استحصال است را ارائه می دهد. روش فوق تناژ و عیار ذخیره قابل استحصال را براساس یک روش زمین آماری غیرخطی تخمین زده [9] که رابطه تناژ - عیار متوسط واحد معدنکاری با ابعاد v را براساس توزیع تجربی نمونه‌های موجود محاسبه می‌کند [9]. روش شرطی‌سازی یکنواخت [10] یکی از این روش‌هایی است که معمولا در معدنکاری برای مدل‌سازی منابع قابل استحصال استفاده می‌شود [11-14].

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