Production geology is an applied science which combines the principles of economic geology and mining engineering to the development of a defined mineral resource.Production geology is responsible to keep the gold production achieve the target with good understanding geology, and characteristic of ore due to metallurgical process,ensure the minerals are efficiently extracted from the deposit, and give information to engineer where the good grade ore places.
Figure 1. Mr. Seno Aji is giving the explanation about production and processing overview in gold mining
There are some terms in ore deposit, such as ore loss is ore that mistaken classified as waste ore throw away due to bad peformance of blasting.Dilution is waste that mixed to ore are and classified as ore.Contamination,usually in grade. High grade mixed to low grade area due to poor mining practice. In production geology , the grade control is the most critical one. Because all missclassification leads to financial loss.
Production geology in organization is under Geology Department and Mining Department. The processes that have to be done in production geology are :
- Drilling. There are 3 kind of drilling such as reverse circulation drilling, tamrock drilling, and diamond/ore drilling which have their own risks and benefits.
- Sampling method using manual splitter or cone splitter.
- Geology mapping has to be done by geologist. There are 2 kinds of geology mapping: wall mapping and floor mapping. Wall maping goals are to help interpretating the mineralization constantly on subsurface or not and to help geologist to detail structure mapping that show if there are mineralization outside the pit or not. Meanwhile, floor mapping is to show the engineer what mineralization that will come up and to help the geologist to domain the area due to estimation model
- Assaying to control the quality before inserted to routine sample.
- Ore control model using resource estimation, using geological data and using geostatistical approach (Variogram).
- Excavating (the removal of waste) and hauling
- Ore storage
- Reconciliation is to compare resource model and actual production.
To result the metal from mineral extraction, ores must to be crushed to the smaller size, grinding ore into finer powder, mineral separation and help leaching. Working on mining has typical risk. Therefore the thing that has to be main concern is work safety. Work safety here is based on UU number 1 year 1970, “Bahwa setiap tenaga kerja berhak mendapat perlindungan atas keselamatannya dalam melakukan pekerjaan untuk kesejahteraan hidup dan meningkatkan produksi serta produktivitas Nasional; bahwa setiap orang lainnya yang berada di tempat kerja perlu terjamin pula keselamatannya; bahwa setiap sumber produksi perlu dipakai dan dipergunakan secara aman dan effisien; Pembinaan norma-norma perlu diwujudkan dalam Undang-undang yang memuat ketentuan umum tentang keselamatan kerja yang sesuai dengan perkembangan masyarakat, industrialisasi, teknik dan teknologi. ”
Figure 2. Mr. Sujarwo is giving the explanation about safety supervisory training
However, the assurance of work safety is only available for those legal mining company. Those legal mining company should be led by KTT (Ketua Teknik Tambang). Based on KEPMEN NO:555.K/26/M.PE/1995 -1 article 1 paragraph (6) “KTT adalah seseorang yang memimpin dan bertanggung jawab atas terlaksananya serta ditaatinya peraturan perundang-undangan K3 pada suatu kegiatan usaha pertambangan di wilayah yg menjadi tanggung jawabnya.”
KTT is helped by safety committee and safety manager also supervises Technical Controller and Operational Controller. They are liable to the external and internal audit and K3 Committee. Technical Controller takes control the mining tools meanwhile the Operational Controller takes control the worker safety. Also they do inspection frequently, analyze the accident, make a report etc. Every legal mining company has mining book which legalized by Mining Inspector. K3 Committee is obeyed to analyze the accident. In order to process the accident report, there are several conditions that have to be accomplished:
The mining accident statistic consists of the frequency rate of the accident in 1 million hours and the rate of serious accident in 1 million hours. The mining accident statistic should be sent by KTT before a month after the end of the year. Also KTT is responsible to follow-up the dangerous incident such as explosion of pressured tube, broken machine, leakage of dangerous substance etc. to KAIT.
Figure 3. Momento giving to the Mr. Adi Tarwoco as the 3rd speaker about environmental control
Besides the protection of work safety, the protection of mining environment is also be the main concern. The management of mining environment is regulated on Kepmen PE No. 1211.K/008/M.PE/1995 about Prevention and Handling of Devastation and Contamination to Mining Activity and UU number 32 year 2009 about protection and management of natural environment. Before do mining activity all that have to do is ask for permission. Mining activity is one of activity that should be had AMDAL. Kind of activity that should have AMDAL are mining and coal activity, metallic mineral, nonmetallic mineral and rocky mineral; the management of purities.
Figure 4. Photo session with all participants and speaker also the committee at the end of session