Effect of quarry dust addition on the performance of controlled low-strength material made from industrial waste incineration bottom ash

The performance of industrial waste incineration bottom ash in controlled low-strength material （CLSM） was investigated in this paper, as the quarry dust was added. CLSM mixtures were made from the industrial waste incineration bottom ash, quarry dust, and cement. Tests for fresh density, bleeding, compressive strength, shear strength, hydraulic conductivity, and excavatability were carried out. The com- pressive strength ranges from 60 kPa to 6790 kPa, the friction angle varies from 5°to 19°, and the cohesion is from 4 to 604 kPa. Most of the mixtures are found to be non-excavatable. It is indicated that the quarry dust addition increases the compressive strength and shear parame- ters, decreases bleeding, and increases the removability modulus.

Assessment of Distribution and Composition of Quarry Mine Dust: Case of Pomona Stone Quarries, Harare

The study aimed at assessing the distribution and composition of dust produced at Pomona Stone Quarry mine in Harare, Zimbabwe. The source contribution to ambient PM2.5 and PM10 dust levels were quantified and their spatial distribution from the quarry to the receptor (community). The study also analysed the pH of soils around the mine, SiO2 and Al2O3 levels in quarry dust. Data was collected through direct observations, personal communications, experiments, soil and dust sampling and analyses. Dust sampling was done in January, April and August, to assess the effect of meteorological conditions on dust concentrations in two phases. Phase 1 was conducted during plant shut down (baseline measurements) while phase 2 was carried out during full plant operations (normal operating conditions), to assess the effect of quarry operations on the surrounding areas. Within the quarry production processes, crushing stage was the most dust emitting stage. Phase 1 dust results showed that both respirable (PM2.5) and inhalable (PM10) dust at all stages were below the legal limit, thus below 35 mg/m3 (respirable) and 180 mg/m3 (inhalable). Highest dust levels (209.9 mg/m3 inhalable and 69.01 mg/m3 respirable) were recorded in August, followed by April (206.9 mg/m3 inhalable and 67.52 mg/m3 respirable) then January (206.82 mg/m3 inhalable and 65.27 mg/m3 respirable). At all stages, highest dust concentrations for both parameters were recorded near the plant and decreased with increasing distance from the plant ( ranging from 209.9 mg/m3 - 19.41 mg/m3 inhalable and 69.01 mg/m3 - 14.23 mg/m3 respirable). This was attributed to the effect of particle size. August recorded the biggest area for both parameters falling within the non-permissible category, followed by April then January. The findings also revealed that the quarry dust contained higher levels of SiO2 (0.752 mg/cm3) which were 7 times higher than the recommended 0.1 mg/cm3 (NSSA). Low Al2O3 levels of 0.102 mg/cm3 were recorded and this was considered as environmentally safe. Soils were slightly acidic-alkaline and the t-test results at 95% confidence interval showed no significant difference between the results from site A and B (p = 0.526). It was concluded that quarry dust from Pomona had no significant effects on soil pH but possible health impacts on the receiving community. The study recommended that dust suppression systems such as water sprays, vegetation, air nets and enclosed production process must be implemented to curb dust emissions.

Evaluating the Stability of Indigenous Akwadum Soil with Cassava Peel Ash and Quarry Dust

Cassava peels are produced as a waste from cassava, which are disposed into landfills. These become an environmental problem;therefore the use of cassava peel ash (CPA) as a soil stabilizer must be encouraged. This study investigates the effects of CPA and quarry dust (QD) on the engineering properties of Akwadum soil behavior, using compaction test, Atterberg limit, and California bearing ratio (CBR). These properties were compared with those of unstabilized soil (original) and soil stabilized with CPA and QD. The natural soil was obtained from a borrowed pit at Akwadum near Koforidua at an average depth of 0.8 m which is meant for road works. This soil sample was stabilized with CPA and QD at 5%, 10% and 20% respectively. The compaction, California bearing ratio and Atterberg limit test were performed on the stabilized soils to thoroughly evaluate them. The results indicate that increasing the percentage of CPA to the natural soil decreases the maximum dry density at increasing optimum water content. The addition of QD at higher percentage increases the maximum dry density at decreasing optimum water content. The results reveal that both QD and CPA improve the engineering properties of the soil with QD providing better results.

Modeling Tensile Strength of Concrete on Partial Replacement of Ce­ment and Sand with Quarry Dust Ground Granulated Blast Furnace and Slag Silica Fumes

Tensile strength of concrete were examined on its partial replacement of cement and sand using ground granulated blast furnace and quarry dust.The study examines its behaviour at different dimensions.This is to monitor the variation effect of these parameters on the growth rates of tensile to the optimum curing age.These include non linear conditions of tensile state,non-elastic and its brittle behaviour at all times as it express zero conditions in tension.This means that it has the ability to with stand pull force.It also reflects its weak ability to handle shear stress thus tends to cause deformation in material as it has poor elasticity.The reflection of its brittle influence the rate of tensile behaviour from concrete ductility.These are known to be a material on modern mechanics of concrete.These are also considered as quasi brittle material.This behaviour was reflected as the system considered evaluating the growth rate of tensile strength that replaced cement and sand with these locally sourced addictives.The developed model monitor other reflected influential parameters such as variation of concrete porosity due it compaction in placements,tensile behaviour reflects these effect that subject it to mechanical properties of concrete.The study expressed the reaction of these parameters in the simulation,the evaluation of these affected the details variation of tensile growth rate at different water cement ratios and curing age.The tensile behaviour that was monitored are based on these factors in the study.The derived model were validated with the a researcher results[24],and both parameters developed best fits correlation.The study is imperative because the system expressed the behaviour of tensile strength from concrete at different dimensions.Experts can applied these concept to monitor tensile behaviour considering these parameters in its growth rates.

Effects of Quarry Activities on some Selected Communities in the Lower Manya Krobo District of the Eastern Region of Ghana

Extraction of Limestone is an economically important and widespread activity in Ghana and has existed since historical times. However, in spite of its remarkable contribution towards economic development, some adverse impacts have been noticed, especially where extraction is carried out without proper planning and use of modern technology and scientific methods. We have carried out an assessment on the environmental effects of limestone quarrying on some communities in the Lower Manya Krobo District in the Eastern region of Ghana. Dust emission is one of the major effects of the practice of limestone extraction and as such, dust (PM10) sampling was conducted at the affected communities. Mean dry season results recorded in these communities stand at 125.0 μg/m3 or Bueryonye, 116.0 μg/m3 at Odugblase and 109.3 μg/m3 at Klo-Begoro. Oterkpolu community which served as the control recorded an average of 50.5 μg/m3. Average rainy season values recorded for the communities were 83.3 μg/m3 for Bueryonye, 113.1 μg/m3 at Odugblase and 74.4 μg/m3 at Klo-Begoro. The control community, Oterkpolu, had 43.3 μg/m3. These values are above the EPA, Ghana daily guideline level of 70 μg/m3 over a time-weighted average per 24 hours. Questionnaires administration and health records obtained from the health facilities in the communities revealed notable deteriorations in the health of the people as a result of the quarrying activities in the area. Notable among these is the prevalence of malaria though not related to dust emissions, it results from mosquitoes breeding in the stagnant pools of water found in pits created as a result of the mining activity. Other common health cases recorded were acute respiratory tract infection, ear and eye infections, cough and pneumonia.

Development of an Effective Method for Preventing Dust Pollution in Stone Quarries Using Petroleum Refinery Wastes

The paper presents a new method for preventing dust pollution in stone quarries using naphthenic wastes of petroleum refineries. The method is based on the use of naphthenate solutions of metals as wetting agents to minimize dust release during stone-cutting process. The studies were carried out in one of the stone quarries of the Absheron peninsula. Initial experiments were conducted by using sodium-naphthenate (RCOONa) solution from alkali wastes of refineries. The results have shown that the use of RCOONa as wetting agent considerably reduces both dust pollution and energy consumption of the used equipment, while increasing the service life of stone-cutting saw. A series of researches were carried out with cupric naphthenate (RCOOCu) to further use the obtained dust-naphthenate mixture in agriculture. The effect of various parameters on the quality of the obtained product was investigated. The investigations have revealed that maximal dust reduction and the good quality of dust-naphthenate mixture were observed with 0.13% solution of RCOOCu at 11° - 13° angle of slope and 100 - 180 rotation∕min. intensity of conveyer.

A Review on Stabilization of Expansive Soil Using Industrial Solid Wastes

In developing countries like India, Industrialization is rising rapidly, and also?a great paucity of land is there, the demand for exploitation of industrial?wastes?which coming from industries is increasing. From geotechnical perspective,?fly ash, granite and quarry waste, cement kiln dust, silica fume, rice husk etc.?are the waste materials?which?have effectual features requisites by an excellent soil stabilization admixture. Stabilization using solid wastes is one of the different?methods of treatment, to improve the engineering properties and make it?suitable for construction. This paper briefs about the recent trends in stabilization of expansive soil using industrial waste (granite and quarry waste, cement kiln?dust, silica fume, rice husk) as stabilizers for decreasing the environmental?hazards.

Use of Stone Dust in the Design of High Performance Concrete

This research evaluated the suitability of stone dust in the design and production of High Perfor-mance Concrete (HPC). HPC mix was designed, tested, costed and a comparison of concrete classes used in the market (Class 25, 30 and 35) done using Cost Benefit Analysis (CBA). The cost benefit was analyzed using Internal Rate of Return (IRR) and Net Present Value (NPV). Laboratory tests established the properties concrete obtained from the design mix. Compressive strength, slump, and modulus of elasticity were tested and analyzed. Structural analysis using BS 8110 was done for a 10 storey office building to establish the structural member sizes. Members obtained from concrete Classes 25, 30, 35 and the new compressive strengths from HPC (Class 80) were obtained and compared. Analysis was done for structural members’ sizes and area freed as a result of de-signing with HPC as well as the steel reinforcement used. To justify the initial cost of HPC if ado- pted, the Cost Benefit Analysis (CBA) was used to estimate increased costs versus income resulting from increased let table space created. The minimum class of concrete used in design was limited to Class 25 N/mm2. The research shows that it is possible to manufacture high strength concrete using locally available stone dust. The stone dust sampled from Mlolongo quarries achieved a characteristic strength of 86.7 N/mm2 at a water cement ratio of 0.32. With the results structural analysis of a 10 storey office structures with columns spaced at 8 meters center to center was de-signed using the four classes and results compared. There was a reduction of columns from 1.2 m wide to 0.65 m wide (over 45%) when concrete class changes from Class 25 to Class 80 creating over 3% of the total space area per floor. Cost benefit analysis using Net Present Value (NPV) and Internal Rate of Return (IRR) presented business case for the use of HPC. With Class 80, the IRR was at 3% and NPV being 8% of the total initial investment. The steel reinforcement increased by 8.64% using Class 30, 11.68% using Class 35 and reduced by 8.37% at Class 80. Further analysis needs to be done to understand the trend of steel reinforcement keeping all the member sizes the same. In this study the member sizes were optimized based on the steel reinforcement and serviceability. This paper provides useful information to design Engineers and Architects and inform future design of multi storey structures.

某露天矿深孔爆破降尘实践

分析了某露天矿深孔爆破爆前、爆中、爆后粉尘的来源,通过若干次试验,采用爆前预湿、水间隔装药、碎石充填、优化孔网等方法,很好地抑制了某石灰石矿深孔爆破产生的扬尘,满足了该矿西南方向某新建大型机场通航安全对降尘的要求。

露天采石场粉尘防治技术分析

为分析露天采石场开采过程中的粉尘危害现状,解决粉尘污染难题,针对露天采石场生产工艺特征,分别提出了爆破作业雾炮抑尘技术、钻机钻孔除尘技术、卡车卸料喷雾抑尘技术、破碎机密闭喷雾降尘技术、筛分作业密闭抽尘净化技术和伸缩落料除尘技术等粉尘防治技术,实现了露天采石场从开采至生产成品全过程中的粉尘治理,极大地降低了露天采石场生产过程中的粉尘浓度,综合降尘效率达85%以上,为露天采石场粉尘防治提供基础依据。

废弃采石场无害化治理探讨

废弃采石场的环境污染严重破坏生态环境,通过采取无害化处理解决生态环境与经济发展的这一矛盾。

铁路采石场除尘和降噪技术

铁路采石场各工序均伴有粉尘和噪声。本文以生产规模20万t/年的采石场为例,分析了道砟生产过程中岩层剥离、开采、破碎、筛分、运输各工序粉尘和噪声污染的产生原因和排放特点。道砟开采阶段可采用喷雾除尘机降尘,生产加工阶段破碎及筛分生产车间可建成封闭式厂房,采用脉冲布袋除尘器和水喷雾系统除尘,成品装卸阶段可加装低压喷雾装置、远距离固定式喷雾除尘机和喷洒速效抑尘剂除尘,效果能满足采石场区域粉尘排放标准要求。建设消声厂房、配置消声器和减震台座等措施治理噪声污染效果较好。在采石场应对粉尘和噪声进行监测,监测结果不达标及时采取措施。

浅谈采石场粉尘产生量及控制措施

目前一些中小城市还存在相当数量的采石场,除对生态破坏严重外,粉尘对周边环境的污染不容忽视。

液压凿岩钻机除尘系统设计

凿岩钻机在采石过程中会产生大量粉尘,为了减少这类粉尘对大气污染、人类的健康危害。本设计采用普通的布袋除尘器,对液压凿岩机在工作中产生的粉尘进行过滤-清灰-再过滤,以达到《大气污染物排放限值》的排放要求。本设计适用范围广泛,安装简单,使用方便,经济、便捷。

基于解释结构模型分析露天采石场粉尘职业危害影响因素

通过对露天采石场进行现场调查、检测和实验室分析,本研究确定了采场和破碎站两个粉尘职业危害重点区域;通过对重点区域进行进一步辨识分析,结果发现,露天采石场粉尘职业危害影响因素主要包括集尘器、除尘系统、安全检查等9个。基于各因素间的相互影响分析,笔者构建了解释结构模型,同时运用相关运算分析各因素的层次并建立递阶结构模型。研究表明,直接影响因素为接尘时间和个体防护,根本影响因素为教育培训和安全检查。研究揭示了各影响因素间的深层次关系,为露天采石场粉尘职业危害防治提供了理论依据。

重庆市某区采石场粉尘与噪声职业危害分析

目的探讨重庆市巴南区露天采石场存在的粉尘、噪声危害程度及职业病防治情况。方法依据国家有关标准,2015年对重庆市巴南区11家采石场工作场所的粉尘、噪声进行检测,并结合采石场工人体检及问卷调查结果进行分析。结果 11家采石场共294名工人(男261人,女33人)。总尘总体超标率为14.07%,破碎和振筛岗位的超标情况最严重(分别为24.32%和40.00%);游离Si O2含量大多在10%以下;总体噪声超标率50.98%;听力异常检出率22.54%,疑似尘肺及职业性手臂振动病检出率均为1.88%;工人对职业卫生防护相关知识知晓率为2.08%~53.13%。结论该市采石场工人接触噪声引起的职业健康损害问题突出,不仅要加强对企业的监督、管理,还要对采石场工人加强培训,增强其对粉尘、噪声的防护意识。

民营石场石工矽肺调查

目的掌握民营石场石工矽肺的发生特点，为矽肺防治工作提供科学依据。方法对某石场进行职业卫生学调查，并对149例接尘石工进行职业健康检查。结果粉尘总尘时间加权平均浓度（TWA）0．10～29．8mg／m，，总尘TwA超标率61．11％，最高超标28．8倍。粉尘中游离二氧化硅含量28．4％。检出石工矽肺18例（壹期12例，贰期6例），检出率12．08％。确诊者平均年龄（38．5±1．6）岁（31～45岁）；接尘工龄（5．0±1．2）年（2．0～7．7年）。发病工种以爆破工（66．67％）居多。患者症状以咳嗽15例（83．33％）、胸闷8例（44．44％），气促7例（38．89％）为主。胸片表现为圆形小阴影“q”占77．78％，“p”影占22．22％。矽肺致残引致劳动能力完全丧失者占33．33％。接尘工人的年龄与检出率之间不存在相关关系（Fs=0．357，P〉0．50）；接尘工人的工龄与检出率之间存在正相关关系（Fs=1．000，P=0．01）。结论石工矽肺发病特征为爆破工发病居多，发病年龄小，发病工龄短，呼吸道症状多，胸片表现主要为圆形小阴影“q”，劳动能力损害较重。应认真做好民营石场石工矽肺预防控告工作．

江阴市从事开山采石接尘农民工晚发型矽肺调查

目的探讨江阴市开山采石接尘农民工晚发型矽肺的发病规律,为相关部门及其他类似企业做好脱尘农民工妥善安置提供政策依据。方法通过中国疾病预防控制中心《健康危害因素监测信息系统》收集2006-2018年江阴市开山采石离岗农民工新发矽肺病历资料,从工种分布、接尘工龄、脱尘年限、晋期等方面进行调查。结果江阴市有857例从事开山采石作业农民工患者在2006年以后表现为脱尘后发病,主要为运搬工337例(占39.3%)、粉碎工148例(占17.3%)、凿岩工133例(占15.5%)。平均接尘工龄20(3~41)年,平均脱尘时间14(1~37)年;初诊矽肺时平均发病年龄62(38~84)岁;其中部分人员一旦发病即是贰期、叁期病例;随着脱尘年限的延长,其初诊发病年龄及接尘工龄均出现逐渐缩短的特征。结论开山采石作业导致的矽肺具有一定的潜伏期,即使在刚脱离粉尘环境时尚属于正常,过若干年仍有部分人员可发展为矽肺患者。对脱尘农民工的健康监护工作非常重要,加强脱尘者管理也是尘肺防治工作的重要内容。

五种职业健康风险评估模型评估小型露天石料矿场硅尘危害比较

目的应用5种职业健康风险评估模型评估小型露天石料矿场硅尘危害风险,为职业健康风险评估方法学的研究提供参考。方法选择7家小型露天石料矿场为评估现场,应用新加坡化学毒物职业暴露半定量风险评估方法 (新加坡模型)、英国健康危害物质控制策略简易法(COSHH模型)、罗马尼亚职业事故和职业病风险评估方法 (罗马尼亚模型)、澳大利亚职业健康与安全风险评估管理导则(澳大利亚模型)、国际采矿与金属委员会职业健康风险评估操作指南(ICMM模型)分别对接触硅尘岗位的职工进行职业健康风险评估。计算5种模型评估结果的风险比值(RR),比较差异性、准确性和相关性。结果新加坡模型、COSHH模型、罗马尼亚模型、澳大利亚模型和ICMM模型评估的RR值分别为0.8、1.0、0.4、0.6和0.8。新加坡模型和澳大利亚模型能明确区分汽车运输驾驶员与洒水车司机接触硅尘的风险水平差异,与这2个岗位的实际风险相符。除COSHH模型外,其他4种模型的RR值间均呈正相关(P<0.05);RR值与浓度比值(CR)均呈正相关(P<0.05),其中新加坡模型的RR值与CR值的相关系数最大,为0.801。结论 5种职业健康风险评估模型中新加坡模型相对更能识别石料矿场不同岗位的硅尘危害风险差异,评估准确性较好,与其他模型具有良好的相关性。

广西40家石灰石露天采场凿岩和破碎岗位粉尘危害状况调查

目的调查分析广西石灰石露天采场凿岩和破碎岗位生产过程中粉尘浓度情况与风险等级。方法2015—2019年对广西40家石灰石露天采场凿岩和破碎岗位职业病危害因素进行检测,通过EASC-IHSTAT对粉尘检测结果进行统计学分析,采用国际采矿与金属委员会(International Commission on Mining and Metals,ICMM)职业健康风险评估法、中国安全生产科学研究院职业卫生定性风险评价法以及GBZ/T 229.1—2010《工作场所职业病危害作业分级第1部分:生产性粉尘》进行职业危害因素风险水平分级。结果石灰石露天采场凿岩和破碎岗位工人接触的石灰石粉尘(呼吸性粉尘)时间加权平均浓度(Concentration time-weighted average,CTWA)平均值分别为(3.645±2.168)和(2.705±1.348)mg/m^(3),超标率分别为37.50%和25.00%;ICMM定量法风险评估模型的评估结果均为不可容忍,职业卫生定性风险评价法评估职业危害因素风险水平均高,工作场所石灰石粉尘危害作业分级均为0级(相对无害作业)至Ⅰ级(轻度危害作业)。两种风险评估模型分级结果大致相同,与检测结果基本一致。结论现有条件下凿岩和破碎岗位石灰石粉尘仍可能会对作业工人的健康造成负面影响,应加强综合防治措施以降低作业人员实际接触水平以及危害的风险程度。