The basis of accurate mineral resource estimates is to have a geological model which replicates the nature and style of the orebody. Key inputs into the generation of a good geological model are the sample data and ma...The basis of accurate mineral resource estimates is to have a geological model which replicates the nature and style of the orebody. Key inputs into the generation of a good geological model are the sample data and mapping information. The Obuasi Mine sample data with a lot of legacy issues were subjected to a robust validation process and integrated with mapping information to generate an accurate geological orebody model for mineral resource estimation in Block 8 Lower. Validation of the sample data focused on replacing missing collar coordinates, missing assays, and correcting magnetic declination that was used to convert the downhole surveys from true to magnetic, fix missing lithology and finally assign confidence numbers to all the sample data. The missing coordinates which were replaced ensured that the sample data plotted at their correct location in space as intended from the planning stage. Magnetic declination data, which was maintained constant throughout all the years even though it changes every year, was also corrected in the validation project. The corrected magnetic declination ensured that the drillholes were plotted on their accurate trajectory as per the planned azimuth and also reflected the true position of the intercepted mineralized fissure(s) which was previously not the case and marked a major blot in the modelling of the Obuasi orebody. The incorporation of mapped data with the validated sample data in the wireframes resulted in a better interpretation of the orebody. The updated mineral resource generated by domaining quartz from the sulphides and compared with the old resource showed that the sulphide tonnes in the old resource estimates were overestimated by 1% and the grade overestimated by 8.5%.展开更多
Coal Bed Methane(CBM)is natural gas occurring in coal seams.It can be used for domestic(heating and cooking)and industrial purposes,electricity generation,transportation(as compressed natural gas or liquefied natural ...Coal Bed Methane(CBM)is natural gas occurring in coal seams.It can be used for domestic(heating and cooking)and industrial purposes,electricity generation,transportation(as compressed natural gas or liquefied natural gas),and in boilers supporting mining operations.It is established that Zimbabwe has CBM in the North-Western region.At the time of this study,only one organization(Industrial Development Corporation)has reported an Original Gas in Place(OGIP)estimate for the region as 765 Bm3.In this study we use Monte Carlo Simulation(MCS)to estimate the range of OGIP values for the region.MCS is a widely used probabilistic method,preferred over deterministic methods in which only best-estimate values of parameters are used to predict a single OGIP value.This single OGIP value may be either positively(overestimated)or negatively skewed(underestimated).However,the probabilistic approach using MCS accounts for the uncertainty in values of parameters.This is done by incorporating appropriate range and probability distributions(e.g.triangular,normal,uniform,etc.)of input parameters(e.g.target area,formation thickness,coal bulk density,and adsorbed methane content),and repeating calculations to generate a cumulative distribution curve for the OGIP.The generated curve provides statistical confidence levels represented as probability distributions,i.e.P10,P50,and P90 represents low,mid,and high probability estimates,respectively.Our results show that P10,P50,and P90 values for the North-Western region OGIP are 5699 Bm3,2347 Bm3,and 706 Bm3,respectively.The Resource Density(RD)estimation is found to range from 0.015 Bm3/km2 to 0.113 Bm3/km2 over the geographic area.This range is comparable to Alberta plains shallow and deep basins in Canada which boosts a higher level of confidence for CBM potential in Zimbabwe.The results are encouraging for further exploration and planning of exploitation of CBM in Zimbabwe.展开更多
Information centric networking(ICN) is a new network architecture that is centred on accessing content. It aims to solve some of the problems associated with IP networks, increasing content distribution capability and...Information centric networking(ICN) is a new network architecture that is centred on accessing content. It aims to solve some of the problems associated with IP networks, increasing content distribution capability and improving users' experience. To analyse the requests' patterns and fully utilize the universal cached contents, a novel intelligent resources management system is proposed, which enables effi cient cache resource allocation in real time, based on changing user demand patterns. The system is composed of two parts. The fi rst part is a fi ne-grain traffi c estimation algorithm called Temporal Poisson traffi c prediction(TP2) that aims at analysing the traffi c pattern(or aggregated user requests' demands) for different contents. The second part is a collaborative cache placement algorithm that is based on traffic estimated by TP2. The experimental results show that TP2 has better performance than other comparable traffi c prediction algorithms and the proposed intelligent system can increase the utilization of cache resources and improve the network capacity.展开更多
The tremendous performance gain of heterogeneous networks(Het Nets) is at the cost of complicated resource allocation. Considering information security, the resource allocation for Het Nets becomes much more challengi...The tremendous performance gain of heterogeneous networks(Het Nets) is at the cost of complicated resource allocation. Considering information security, the resource allocation for Het Nets becomes much more challenging and this is the focus of this paper. In this paper, the eavesdropper is hidden from the macro base stations. To relax the unpractical assumption on the channel state information on eavesdropper, a localization based algorithm is first given. Then a joint resource allocation algorithm is proposed in our work, which simultaneously considers physical layer security, cross-tier interference and joint optimization of power and subcarriers under fairness requirements. It is revealed in our work that the considered optimization problem can be efficiently solved relying on convex optimization theory and the Lagrangian dual decomposition method is exploited to solve the considered problem effectively. Moreover, in each iteration the closed-form optimal resource allocation solutions can be obtained based on the Karush-Kuhn-Tucker(KKT) conditions. Finally, the simulation results are given to show the performance advantages of the proposed algorithm.展开更多
文摘The basis of accurate mineral resource estimates is to have a geological model which replicates the nature and style of the orebody. Key inputs into the generation of a good geological model are the sample data and mapping information. The Obuasi Mine sample data with a lot of legacy issues were subjected to a robust validation process and integrated with mapping information to generate an accurate geological orebody model for mineral resource estimation in Block 8 Lower. Validation of the sample data focused on replacing missing collar coordinates, missing assays, and correcting magnetic declination that was used to convert the downhole surveys from true to magnetic, fix missing lithology and finally assign confidence numbers to all the sample data. The missing coordinates which were replaced ensured that the sample data plotted at their correct location in space as intended from the planning stage. Magnetic declination data, which was maintained constant throughout all the years even though it changes every year, was also corrected in the validation project. The corrected magnetic declination ensured that the drillholes were plotted on their accurate trajectory as per the planned azimuth and also reflected the true position of the intercepted mineralized fissure(s) which was previously not the case and marked a major blot in the modelling of the Obuasi orebody. The incorporation of mapped data with the validated sample data in the wireframes resulted in a better interpretation of the orebody. The updated mineral resource generated by domaining quartz from the sulphides and compared with the old resource showed that the sulphide tonnes in the old resource estimates were overestimated by 1% and the grade overestimated by 8.5%.
文摘Coal Bed Methane(CBM)is natural gas occurring in coal seams.It can be used for domestic(heating and cooking)and industrial purposes,electricity generation,transportation(as compressed natural gas or liquefied natural gas),and in boilers supporting mining operations.It is established that Zimbabwe has CBM in the North-Western region.At the time of this study,only one organization(Industrial Development Corporation)has reported an Original Gas in Place(OGIP)estimate for the region as 765 Bm3.In this study we use Monte Carlo Simulation(MCS)to estimate the range of OGIP values for the region.MCS is a widely used probabilistic method,preferred over deterministic methods in which only best-estimate values of parameters are used to predict a single OGIP value.This single OGIP value may be either positively(overestimated)or negatively skewed(underestimated).However,the probabilistic approach using MCS accounts for the uncertainty in values of parameters.This is done by incorporating appropriate range and probability distributions(e.g.triangular,normal,uniform,etc.)of input parameters(e.g.target area,formation thickness,coal bulk density,and adsorbed methane content),and repeating calculations to generate a cumulative distribution curve for the OGIP.The generated curve provides statistical confidence levels represented as probability distributions,i.e.P10,P50,and P90 represents low,mid,and high probability estimates,respectively.Our results show that P10,P50,and P90 values for the North-Western region OGIP are 5699 Bm3,2347 Bm3,and 706 Bm3,respectively.The Resource Density(RD)estimation is found to range from 0.015 Bm3/km2 to 0.113 Bm3/km2 over the geographic area.This range is comparable to Alberta plains shallow and deep basins in Canada which boosts a higher level of confidence for CBM potential in Zimbabwe.The results are encouraging for further exploration and planning of exploitation of CBM in Zimbabwe.
基金supported by the National High Technology Research and Development Program(863)of China(No.2015AA016101)the National Natural Science Fund(No.61300184)Beijing Nova Program(No.Z151100000315078)
文摘Information centric networking(ICN) is a new network architecture that is centred on accessing content. It aims to solve some of the problems associated with IP networks, increasing content distribution capability and improving users' experience. To analyse the requests' patterns and fully utilize the universal cached contents, a novel intelligent resources management system is proposed, which enables effi cient cache resource allocation in real time, based on changing user demand patterns. The system is composed of two parts. The fi rst part is a fi ne-grain traffi c estimation algorithm called Temporal Poisson traffi c prediction(TP2) that aims at analysing the traffi c pattern(or aggregated user requests' demands) for different contents. The second part is a collaborative cache placement algorithm that is based on traffic estimated by TP2. The experimental results show that TP2 has better performance than other comparable traffi c prediction algorithms and the proposed intelligent system can increase the utilization of cache resources and improve the network capacity.
基金supported by the National Natural Science Foundation of China under Grant No.61371075the 863 project SS2015AA011306
文摘The tremendous performance gain of heterogeneous networks(Het Nets) is at the cost of complicated resource allocation. Considering information security, the resource allocation for Het Nets becomes much more challenging and this is the focus of this paper. In this paper, the eavesdropper is hidden from the macro base stations. To relax the unpractical assumption on the channel state information on eavesdropper, a localization based algorithm is first given. Then a joint resource allocation algorithm is proposed in our work, which simultaneously considers physical layer security, cross-tier interference and joint optimization of power and subcarriers under fairness requirements. It is revealed in our work that the considered optimization problem can be efficiently solved relying on convex optimization theory and the Lagrangian dual decomposition method is exploited to solve the considered problem effectively. Moreover, in each iteration the closed-form optimal resource allocation solutions can be obtained based on the Karush-Kuhn-Tucker(KKT) conditions. Finally, the simulation results are given to show the performance advantages of the proposed algorithm.
