天然气水合物开采技术研究进展

天然气水合物具有分布范围广、存储层规模大、储层浅、燃烧能量密度高等优点,是一种将来能够代替煤炭等传统能源的高效洁净能源,目前对天然气水合物的开采方法有热激法、降压法、注入抑制剂法、置换法及注热+降压联合开采天然气水合物法等,并对不同开采方法进行评价。     

Why software repositories are not used for defect-insertion circumstance analysis more often: A case study

ContextRoot-cause analysis is a data-driven technique for developing software process improvements in mature software organizations. The search for individual process correlates of high defect densities, which we call defect insertion circumstance analysis (DICA), is potentially both effective and cost-efficient as one approach to be used when attempting a general defect root cause analysis. In DICA, data from existing repositories (version archive, bug tracker) is evaluated largely automatically in order to determine conditions (such as the people, roles, components, or time-periods involved) that correlate with higher-than-normal defect insertion frequencies. Nevertheless, no reports of industrial use of DICA have been published.ObjectiveDetermine the reasons why DICA is not used more often by practitioners.MethodWe use a single-case, typical-case, revelatory-type case study to evaluate in parallel the importance of six plausible reasons (R1–R6). The case is based on 11 years of repository data from a small but mature software company building a product in the high-end content management system domain and describes a four person-months effort to make use of these data.ResultsWhile DICA required non-negligible effort (R3) and some degree of inventiveness (R2), the most relevant roadblock was insufficient reliability of the results (R6) combined with the difficulty of assessing this reliability (R5). We identify three difficulties that led to this outcome.ConclusionCurrent repository mining methods are too immature for successful DICA. Gradual improvements are unlikely to help; different principles of operation will be required. Even with such different techniques, issues with input data quality may continue to make good results difficult-to-have.     

破碎围岩预控分段嗣后充填技术研究与实践

针对破碎围岩稳定性差、深部矿压显现剧烈等难题,结合大尹格庄金矿现有采矿工艺,提出预控顶分段嗣后充填技术。在阐述预控顶分段嗣后充填技术特点、施工工艺、技术关键的基础上,采用正交实验优化充填材料配比,重点采用理论分析和数值模拟相结合的方式优化设计采场结构参数。实践表明,预控顶分段嗣后充填技术在各矿得到广泛应用,效益显著。     

A COMPARISON OF GOTHIC ELITE AND STANDARD ELITE TYPE FACES

Two forms of type face, Gothic Elite and Standard Elite, wore compared for readability (i) when the emphasis was on comprehension and (ii) when it was on speed. No significant difference was found between the reading times for the two typo faces when reading for comprehension but Standard proved superior to Gothic when speed was the more important. Possible reasons for these differing results under the two conditions are considered.     

Transport in the minerals industry – Contributions to greenhouse gas emissions and potential for mitigation

The extraction of primary ores and the end user of the contained minerals are typically separated by large distances. Under current paradigms, the transportation of minerals is powered by fossil fuels, which produce significant greenhouse gas emissions (GHG). Off-site greenhouse gas emissions from transportation of mineral products are not currently considered to be within the scope of influence of the mineral industry except in those cases where the company owns and operates the transport fleet. The significance of these emissions has therefore not been regularly accounted for. This paper presents the results of a study conducted by the authors of the emissions from transportation of Australian minerals (as one of the world’s key minerals producers). The results indicated that an estimated 4.4Mt of CO₂-equivalent was produced domestically by transportation in 2008. This is equivalent to 6% of other emissions from the Australian minerals industry (McLellan, 2009). Estimates of the emissions from export shipping of Australian bulk minerals indicated that an additional 96.4Mt of CO₂-equivalent is produced from this source, which is 20% greater than the entire on-site and off-site electricity generation emissions from the Australian minerals industry. Possible mitigation options were examined, with fuel substitution for biodiesel, natural gas or hydrogen showing the highest potential in the medium to long term.     

Risk analysis,regulation proposal and technical guide for pilot tests of hydrogen vehicles in underground mining

Safety related issues, regarding the use of hydrogen technologies have raised great concern in the industry, especially in mining, due to confined places where hydrogen leaks can accumulate and eventually cause a fire hazard or explosion. Currently, there are no sufficiently robust regulations or experiences regarding the use of hydrogen in mining, which must be resolved to design safety models, pertinent regulations and a strategy to guide the use of hydrogen. This article qualitatively and quantitatively analyzes the risks of a HFCV pilot project, identifying these risks to determine how they are involved in mining operations and evaluates how dangerous these are in this environment. This is achieved through a HAZOP study and using the F&EI, where the results contribute to the knowledge of hydrogen technologies. One of the strongest results obtained by using the F&EI, shows that a vehicle fueled by hydrogen (5 kg at 700 bar) in full operation presents an index of 153.0, a vehicle of similar characteristics fueled with natural gas (20 kg at 200 bar) will present a value of 197.1. Therefore, if the use of natural gas is authorized in underground mining, hydrogen that can be an even safer alternative, should be authorized too. Moreover, the results show that there is a similar probability with diesel (60 kg at 1 bar) of causing a potential incident, in addition, the HAZOP indicates that as long as hydrogen leaks are kept under control with adequate ventilation and appropriate vehicle design, the system becomes even more robust, which would be achieved by including additional infrastructure security measures to mitigate events of fire and explosion.     

固体钾盐地下开采工艺与设备配套技术研究

为了研究连续采煤机开采工艺与设备在固体钾盐矿床地下开采中的应用情况,根据老挝龙湖钾镁盐矿区矿层地质条件,分析了首采区2盘区1区段的开采工艺、设备配套方式、设备适用性等。研究结果表明连续采煤机—梭车(间断式运输工艺系统)对地质条件有着较强的适应性,可通过改变连续采煤机截割方式和减小切入矿体的深度来提高连续采煤机截割矿体的效率。该开采方法的成功应用,不仅改变了传统开采方式,而且提高了机械化水平和资源回收率。研究结果为扩大连续采煤机的应用范围奠定了基础,也为类似条件下固体钾盐资源的开采提供了崭新的模式。     

综放工作面过运煤公路下开采技术

为了解决公路下安全高效开采技术问题,将工程实践、岩移观测、数值计算、理论分析相结合,对黄土沟壑区开采沉陷特征及公路下开采技术进行了研究。结果表明:由于煤层埋藏浅,第四系冲积层厚度大强度低,覆岩破坏剧烈,导水裂缝带直达地表,综放回采初期在上下顺槽内侧和切眼外侧出现台阶裂缝,裂缝走向与回采边界平行,落差较小;煤层开采达到或超过充分采动后在回采边界岩体沿煤壁整体切落,地表出现大的台阶裂缝;地表台阶裂缝的出现受地形影响比较明显,边坡土体在重力作用和开采沉陷影响下,地表裂缝更加发育;路基下部的厚黄土层可吸收部分开采沉陷变形,对减轻公路破坏发挥了一定作用;可按台阶裂缝角划定公路保护煤柱,煤柱内不放煤,地表及时采取措施可实现公路的安全运行。研究成果为相似地质条件公路下煤矿开采提供了技术参考。     

矿区废弃地再利用与体育场地建设

矿山废弃地占用大量土地资源,对生态环境也有着巨大的破坏作用。本文通过对矿区废弃地改造模式进行探讨,初步提出了矿区废弃地改造为体育场地的开发模式,结合相关案例对体育场地可建设类型及适用范围进行了分析,并为矿区体育场地建设提出制度保障及政策性建议。将废弃工矿区土地再利用与体育设施建设相结合,在改善矿区环境的同时不仅能够加快矿区产业转型,更能促进社会体育公共服务发展。