The application of probabilistic logic to identify, quantify and mitigate the uncertainty inherent to a large surface mining budget

Mining is a hugely expensive process and unlike manufacturing is based on an ever diminishing resource. It requires a continuous infusion of capital to sustain production. A myriad of factors, from the volatility of the markets to the surety that the minerals are really there, “plagues” both management and investors. The budget tries to predict or forecast future profits and acts as a roadmap to all stakeholders. Unfortunately, most of the time the budget of a mine degenerates to the extent of a collapse, sometimes very soon into the new budget period. This problem plagues both small and large mines indiscriminately. The budget is dictated in absolutes, and little or no variability is allowed. This thesis aims at developing a process to predict the probability of failure or success through the application of probabilistic logic to the simulation of the budget. To achieve this, a very detailed modelling tool is required. The model must replicate the actual mining process both in time and actual spatial representation. Enabling technology was developed over a period of five years, primarily based on the Runge Software Suite. The use of activity based costing enabled the budget to be simulated and expressed as a probability distribution. A Pareto analysis was done on the main cost drivers to extract the most important elements – or key drivers - that need to be manipulated. These distributions were mapped against real data and approximated with the use of the three parameter Weibull distribution. Simulation using Xeras® (Runge) proved to be impossible. This is due to the time needed for setup and processing. The budget was described as an empirical function of the production tonnages split according to the Pareto analyses. These functions were then utilised in Arena® to build a stochastic simulation model. The individual distributions are being modelled to supply the stochastic drivers for the budget distribution. Income, based on the sales, was added to the model in order for the Nett profit to be reflected as a distribution. This is analysed to determine the probability of meeting the budget. The underlying analysis of an open pit mining process clearly reflects that there are primary variables that may be controlled to trigger major changes in the production process. The most important parameter is the hauling cycle, because the haul trucks are the nexus of the production operation. It is further shown that the budget is primarily influenced by either FTE’s (full time employees, i.e. bodies) or funds (Capex or Opex) or a combination of both. The model uses probabilistic logic and ultimately culminates in the decision of how much money is needed and where it should be applied. This ensures that the probability of achieving the budget is increased in a rational and demonstrable way. The logical question that arises is: “Can something be done to utilise this knowledge and change behaviour of the operators?” This led to (IOPA – Intelligent Operator Performance Analyses) – where the performance or lack thereof is measured on a shift by shift basis. This is evaluated and communicated through automated feedback to the supervisors and operators and is being implemented. Early results and feedback are hugely positive. The last step is prove where capital (or any additional money spend) that is applied to the budget will give the most benefit or have the biggest positive influence on the achievement thereof. The strength of the model application lies therein that it combines stochastic simulation, probability theory, financial budgeting and practical mine schedule to predict (or describe) the event of budget achievement as a probability distribution. The main contribution is a new level of understanding financial risk and or constraints in the budget of a large (open pit) mine.Dissertation (MSc)--University of Pretoria, 2014.Mining EngineeringMEngUnrestricte

a clinical observation of vascular complications after ocular surgery

Background. Ocular vascular occlusions following intraocular procedures are a rare complication. We report a case series of patients with retinal vascular occlusions or anterior ischemic optic neuropathy (AION) after anterior and posterior segment surgery and demonstrate possible risk factors. Methods. Observational case series. Results. In ten patients, vascular occlusions were observed within ten weeks after intraocular surgery: branch retinal arterial occlusion (BRAO) (n = 2), central retinal artery occlusion (CRAO) (n = 2), central retinal vein occlusion (CRVO) (n = 1), branch retinal vein occlusion (BRVO) (n = 1), anterior ischemic optic neuropathy (AION) (n = 3), and combined central artery and vein occlusion (n = 1). AION occurred later (27–69 d) than arterial occlusions (14–60 d) or venous occlusions (1-2 d). In all cases, either specific surgical manipulations or general vascular disorders were identified as risk factors. In addition to general cardiovascular risk factors (arterial hypertension n = 6, diabetes mellitus n = 4), internal workup disclosed bilateral stenosis of the carotid arteries (n = 1) and myeloproliferative syndrome (n = 1). Conclusion. Vascular occlusions after surgical ocular procedures seem to be more frequent when cardiovascular diseases coexist. Surgical maneuvers and intra- or postoperative pressure changes may act as a triggering mechanism in patients with underlying systemic cardiovascular disorders. Affected patients should undergo thorough internal examination to identify possible underlying diseases

Vascular Occlusions following Ocular Surgical Procedures: A Clinical Observation of Vascular Complications after Ocular Surgery

Background. Ocular vascular occlusions following intraocular procedures are a rare complication. We report a case series of patients with retinal vascular occlusions or anterior ischemic optic neuropathy (AION) after anterior and posterior segment surgery and demonstrate possible risk factors. Methods. Observational case series. Results. In ten patients, vascular occlusions were observed within ten weeks after intraocular surgery: branch retinal arterial occlusion (BRAO) (n=2), central retinal artery occlusion (CRAO) (n=2), central retinal vein occlusion (CRVO) (n=1), branch retinal vein occlusion (BRVO) (n=1), anterior ischemic optic neuropathy (AION) (n=3), and combined central artery and vein occlusion (n=1). AION occurred later (27–69 d) than arterial occlusions (14–60 d) or venous occlusions (1-2 d). In all cases, either specific surgical manipulations or general vascular disorders were identified as risk factors. In addition to general cardiovascular risk factors (arterial hypertension n=6, diabetes mellitus n=4), internal workup disclosed bilateral stenosis of the carotid arteries (n=1) and myeloproliferative syndrome (n=1). Conclusion. Vascular occlusions after surgical ocular procedures seem to be more frequent when cardiovascular diseases coexist. Surgical maneuvers and intra- or postoperative pressure changes may act as a triggering mechanism in patients with underlying systemic cardiovascular disorders. Affected patients should undergo thorough internal examination to identify possible underlying diseases

Als der Wohl-Edle, Großachtbare und Wohlgelahrte Herr Joh. Gottlieb Vater, Aus Torgau Der Heiligen Schrifft eyfrigst Beflissener, Die Universität Wittenberg Nach rühmlichst daselbst geführten Studien verließ, Und den 30. September Anno MDCCXIX. Seine Abreise nach Leipzig nahm. Wolten Gegen Demselben Jhre Ergebenheit an den Tag legen, Drey Desselben gute Freunde

Abschiedsgedicht auf Johann Gottlieb Vater, stud. theol., 30. Sept. 1719Autopsie nach dem Ex. der ULB Sachsen-AnhaltVorlageform des Erscheinungsvermerks: Wjttenberg, Gedruckt in der Fincelischen Buchdruckerey

Johann Georg Hagers ... Ausführliche Geographie

von Johann Georg HagerTitelblatt von Bd. 1 fehlt.Bd. 1: [15] Bl., 1131 S., [95] Bl. ; Bd. 2: Titelblatt, [6] Bl., 1184 S., [96] Bl. ; Bd. 3: Titelblatt, [7] Bl., 1028 S., [107] Bl

Iudicium Et Consilium Medicum, Uber die zu dieser Zeit Grassirende Durchfälle : Wie man sich dabey verhalten/ praeserviren und mittelst Göttlichen Segens curiren solle/ Auff Anordnung Der Hoch-Fürstl. Sächs. Erblandes-Regierung zu Weißenfels

Jedermann zum besten eröffnet Von Johann Joachim Hagern/ Med. D. Prof P. & Phys

Kiri tundmatule, Leipzig

http://tartu.ester.ee/record=b1860405~S1*es

Zu dem höchsterfreulichen hohen Geburthstage der Durchlauchtigsten Fürstin und Frau, Frau Maria Amalia Augusta, Herzogin zu Sachsen, Jülich, Cleve und Berg ... gebohrner Pfalzgräfin von Zweybrück [et]c. den 10. May 1772. wollte in tiefster Demuth ihren unterthänigsten Glückwunsch bey einer angestellten Redeübung darbringen die Schule zu Chemnitz

durch M. Johann Georg Hagern, Rect.Autopsie nach Ex. der ULB Sachsen-AnhaltVorlageform des Erscheinungsvermerks: Chemnitz, gedruckt bey Johann Caspar Philipp Groll

De Consvetvdine. Signo. Crvcis. Vtendi Havd. Invenvsta Disserit. Simvl. Qve Ad Actvm. Valedictorivm D. XIII. Calend. Novembr. A. R. S. MDCCLXVI. Hora. Nona. Institvendvm Scholae. Nostrae. Inspectores Gravissimos. Omnes. Qve Patronos. Atqve. Favtores Ea. Qva. Par. Est. Pietate Invitat M. Ioan. Georg. Hager Rector

Vorlageform des Erscheinungsvermerks: Chemnicii Litteris. Petri. Christ. Iahnii