SUMMARY RM9

Sanda KRAUSZ, Piotr M. SOLOZHENKINThe Process Parameters Dynamics at The Flotation with Released Air from Pulp

One of the most up to date for the worldwide mineral flotation is to assure an improvement to the flotation selectivity of the ultra fine materials. These problems appeared because of the necessity to process ores with small contents of useful substances, fine disseminated. By advances grinding, an important part of materials has dimensions under 30 - 40 micrometers. In this conditions, the results of “classic” flotation are unsatisfactory, with metal loss do to a low floatability of very fine particles; that’s why are recommended the special flotation methods e.g. the flotation with air released from pulp. This process is well known, but with small applicability in practice, may be because of a less knowledge of specifically theoretical basis.The main advantage of this procedure on separating very fine particles is the formation of the air bubble onto the hydrophobic solid surface of the floatable particles. The drawback concerning the very small probability of taking place the collision of these particles with the air bubbles, typical to such sizes, is thus removed and separation selectivity much improved. Our paper presents some new aspects and the research results of the flotation with air released from pulp are studied: the influence of the pressure reducing in the system atmosphere function form, and the possibilities of assuring a regime corresponding to a maximum floatability of the material from certain grading class and an optimal selectivity of the process.

Eugen COZMA, Ilie ONICA, Cornel HIREANStability Analysis of Anton Bell-Shape Room (Turda Saline)

This paper presents the stability analysis of Anton mine, Turda saline, taking into consideration an analytical model of calculus for a bell-shape of excavation and a 3D finite element numerical model. The results of the calculus confirm that the Anton mine remains stable.

Valeriu PLESEAThe Undermined Coal Bed Exploitation Method - Subject of The Dispute Regarding Alignment to Technical, Economical and Security Request of Hard Coal Exploitation in Jiu Valley

As a conjuncture necessity registered in Jiu Valley mining, effect of activity restructuring and massive staff reduction after 1989, respective the adverse technical-financial situation at that point at CNH Petrosani regarding the lack of investments founds for achievement of performing working equipments and materials, the undermined coal bad exploitation method has been first time applied for low inclination of coal bed (bed no. 3), being gradual generalized for entire range of conditions, respective medium and high pitch (aBED > 22°).Connected to the conformity aspects of the method with technical, economical and security requests necessary for the optimum coal exploitation bed, aspects that have generated after the tragically events form Petrila Mine a series of contradictory discussions regarding the entry of the method and its fallowing application to coal basin conditions from Jiu Valley, within the paper is presented the stage of research-design works that have stayed on the basis of afferent technologies elaboration and implementation, prognostics of the existent Framework Project documentation, concerning application conditions and insurance of optimum security and bedding protection climate, and as a part of the conclusions and proposals made for identification of the interested factors about the real situation and making appropriated decisions for continuous improvement and development of exploitation activity.

Ferenc KORONKA, Francisc TAKACS, Iosif ANDRASThe Influence of Rock Properties on The Wear of Mining Tools for Rotating Drilling

Taking into account the advantages of the rotating drilling versus the percussive one, it is necessary to manufacture removable drilling bits for rotating drilling in hard rocks. The actual level of the knowledge

regarding the rock cutting does not allow an adequate mathematical description of the interaction between the tool and the rock in case of rotating drilling. In conclusion the experimental tests represent the main means used for the assessment of the possibilities to perform constructive modifications of the tools or appropriate drill hammer design. In the paper the results of the tests performed on a testing rig regarding the rotating drilling are presented.

Iosif DUMITRESCU, Adriana ZAMORAAdaptation of The Advance System for KS-3M Shearer Adapted for 295-842 Rybnik Conveyer

The paper presents technical solutions to correlate the function of KS-3M shearer with Rybnik 295/842 conveyer in order to observe Occupational Health and Safety requirements.These machines, alongside of CMA-5H powered support make up a powered face complex used to extract coal in panel 4/seam 3/block VI.

Cristian Marcel FELEAAn Intuitive-Empirical Analysis of The Economic and Financial Difficulties The National Hard Coal Company is Experiencing

An intuitive-empiric analysis of a phenomenon allows both “a priori” and “a posteriori” judgment about his present and future evolution. Such an analysis doesn’t require many pieces of information; it’s enough to work with common information. Common information about National Hard Coal Company referring to historical debt owing national budget can be a start for such an intuitive-empiric analysis. Something must occur if this company is in such a bad shape, this is the a priori judgment. Looking to some financial information published in national or local media, doing some calculations, we have an a posteriori judgment.

Emil GHERMAN, Maria TOFANA, Emilia Angela GHERMANApplications to The Value of Engineering Optimization Criteria a Solutions for Applicative Research

Description of applied statistical methods, based on “value engineering”, used for analyzing and selecting optimal solutions in a project with applicative research highlighting the importance that the research in economics and efficiency of funding in scientific research.

Florea NEAGUDimitrie Alexandru Hillard at Eighty Years

This article presents engineer Dimitrie Alexandru Hillard activity, at the anniversary of 80 years.