Large-size Sb and As geochemical anomalies were discovered in Heidashan area by 1∶200000 regional geochemical exploration, and then two antimony mineralized belts were detected through anomaly appraisal. The Heidashan area is located in the antimony prospective district and hence has favorable geological conditions and great potential for mineralization and oreprospecting.

In this paper, the authors made a detailed processing and interpretation of aeromagnetic data obtained from Yemashan area of Qinghai Province, studied magnetic susceptibilities of intrusive bodies and ores as well as characteristics of regional magnetic field, and explained the fault structural system and the distribution of volcanic rocks in the study area. On such a basis, the relationship between the spatial distribution of irondominated polymetallic ore resources and magnetic anomalies is analyzed, the oreprospecting criteria are established, and the ore potential is predicted.

Using more than ten thousand data collected in the past 20 years since the beginning of geochemical prospecting in the West Qinling area and adopting computer and GIS technology,the authors selected and studied five key oreforming elements of Au,Cu,Pb,Zn and W. Starting with geochemical features,the authors investigated their migration,enrichment and dispersion in time and space. Based on probing into their geochemical characteristics in such areas as Beishan, Qilian Mountains and West Qinling,the authors obtained complete,detailed and systematic geochemical outcomes, which provide theoretical basis for geochemical prognosis of regional ore deposits.The main prospective areas and favorable zones for exploration are pointed out,which is most helpful to further ore-prospecting work.

In the process of prospecting for concealed faults in the Shitingjiang area by means of the remote-sensing geological interpretation,local special riverbed and river shoal landform has hindered the researchers from the application of some common geophysical-geochemical methods.In this paper,the geogas prospecting method was employed to obtain the location and breadth information of local concealed faults.It is shown that geogas prospecting can not only verify the reliability of remote-sensing interpretation but also offer more accurate location information,thus providing important help for the exploration of local geothermal resources.In river bed and river shoal areas,the influence of the surface environment on the accumulative geogas prospecting is insignificant,which is different from things of other common geophysicalgeochemical methods.The accumulative geogas prospecting has fairly good environmental adaptability and practicability.

At the beginning of the 1990 s, the authors carried out ecological environment geochemical investigation in Hangjiahu plain, Ningshao plain, Jinqu Basin and Jinqu plain and, as a result, obtained thousands of analytical data and compiled various kinds of relevant maps and manuals. On the basis of these materials and through technical management,the authors finally acquired threshold contents of soil elements in the whole province.

 A great challenge to economic geologists is the effective and quick locating of mineralization and the supply of basic areas for scientific drill hole arrangement.Great attention has been paid to gas geochemistry because gas can easily migrate through different overburdens and gas anomalies can indicate underlying mineralizations directly or indirectly.After decades of development,a significant improvement has been made in gas geochemical survey in such aspects as indicators,analytical and sampling methods,and data processing and interpretation.With the utilization of GCMS as a routine analytical tool for gas analysis,the determination of a suite of ultratrace level compounds with extremely low detection limits has become possible.In recent years,several new gas geochemical approaches have been developed in the Western Countries,which prove to be effective for exploring concealed or blind ore bodies.This paper has briefly summarized the development of gas geochemical survey,sampling and analytical methods,main indicators and factors related to gas survey.A new gas geochemical survey (SDP) technology is emphatically discussed in this paper in the aspects of the principle,applying and analytical methods,and case studies.

This paper deals with the present research situation of the numerical simulation and imaging technology for crosshole electromagnetic wave. In the forward aspect, the advantages and disadvantages of such methods as finite difference, finite element and integral equation as well as their development trend are discussed. In the inversion aspect, mainly linear and nonlinear inversions are analyzed, with a detailed discussion on the linear inversion methods both in the time domain and in the frequency domain as well as a prediction of their future development trend.

 Based on an analysis of the frequency sounding curve of the CSAMT method (controlled source audio-frequency electromagnetic method), the authors have found that the  curve intersects the curve in the transition region. The physical mechanism of such a phenomenon was studied, and a method for correcting the  curve in the transition region was put forward. It is shown that the corrected   curve is quite consistent with the actual stratigraphic electric character.

Beginning with the present situation of radon researches in China and abroad and the basic theory in radon measurement with active carbon, this paper has analyzed the factors affecting the application of this method. On such a basis, the data processing of this method is discussed. The method was used to detect the underground workedout area in Nanyan Village of Gujiao, with a good result obtained.

As radon gas has such physical-chemical characteristics as reluctance to liquidation, good stability and strong dispersion capacity, it can not only concentrate in the natural gas accumulation but also migrate vertically to the surface. Radon has three kinds of sources: atmospheric radon, crust-derived radon and mantle-derived radon. 3He is derived mainly from the mantle, 4He comes mainly from the crust, and R/Ra is commonly used to signify the source of radon. Radon gas has rich natural gas geological implications: the surface radon gas concentration has certain oil-gas indication significance, and the isotopic distribution characteristic value of radon gas R/Ra has such geological implications as the indication of the oilgas structural environment and fault zone and the implication of the genesis of the CO2 gas accumulation.

Fractal characteristics of elements As , Cd , Cr , Cu , Hg , Pb , Zn and Ni contained in surface and deep-seated geochemical samples from Taiyuan basin were analyzed and studied in detail. The background sections, singularity sections and multifractal dimensions of these eight elements were determined, which were taken for the classification study. On such a basis, their concentration trends were tentatively analyzed. It is held that there exists considerable difference between the surface and deep-seated layers, and that the surface layer has stronger concentration trend than the deep layer. The result of this study provides a credible basis for soil quality assessment in Taiyuan basin.

According to the grade evaluation criteria of heavy metal pollution, the authors carried out the pollution grade evaluation for soil heavy metals in Taiyuan basin using the ideal point method. Two means were chosen for the evaluation: one includes the reference value of the grade standard in the evaluation criteria as the biggest level of the pollution grade, and the other only considers the 1st ~ 5th level of the evaluation standard value, with no consideration given to the reference value. It is shown that the first means weakens the whole pollution situation of Taiyuan basin, whereas the second means can separate pollution degrees of various areas preferably and reflect the pollution situation specifically, thus fairly satisfactorily preserving the pollution information. The evaluation results indicate that the points of relatively low pollution degrees are concentrated in mountain areas, while the points of rather high pollution degrees are distributed along the Fenhe River valley. As for urban pollution, Taiyuan, Yuci and Fenyang-Xiaoyi areas are subjected to rather heavy pollution, Taigu and Qixian possess the second place, and the soil environment of Qingxu, Jiaocheng, Wenshui and Pingyao is comparatively clean.

The extraction of ore-prospecting geochemical information from regional geochemical data is an important subject in geochemical exploration, and the division of geochemical backgrounds and anomalies is the key to the extraction of ore-prospecting geochemical information. Stream sediments are weathering products of rocks and natural material assemblages from the upstream catchment basin, thus having obvious inheritance relationship with rocks of the upstream catchment basin in chemical composition. The content of ore-forming and halo-forming elements is also closely related to major elements. Based on characteristics of stream sediments, the authors adopted the geochemical zoning standardized method to delineate geochemical anomalies. Case studies show that the application of major elements to the division of geochemical zones is effective. The false anomaly in the high background area can be suppressed and the mineralization anomaly in the low background area can be intensified by zoning standardized data processing, thus enhancing the prospecting information. The composite mineralization anomalies are delineated by factor scores of ore-forming and major elements, which can make prominent the ore-induced information.

Tunnel engineering is an important component part of such large-scale engineering projects as railway, highway, water conservancy and hydropower constructions. Unclear geological conditions have frequently led to considerable harmfulness caused by tunnel construction accidents. Therefore, the improvement of the advanced geological forecast for tunnel construction is very necessary. The study of tunnel seismic wave advanced forecast technology has been carried out both in China and abroad in the past several years. In this paper, the author has discussed the present situation and existent problems in this aspect, pointed out the deficiency of the TSP technology, dealt with the importance of overcoming blindness and improving scientific forecast, and described the newly-developed TGP tunnel seismic forecast system and its technology as well as its application effects.

Based on seismic attributes of the time window, the authors studied the methods of first arrival wave pickup by using energy ratio. A comparison was made in theory and application effects of statistical energy ratios between such means as solid, rolling and changing time windows. The results show that the effects of solid and rolling time windows are relatively poor, with considerable errors existent in the process of picking some special points. When the transform length of the time window statistical method is employed, the event of the first arrival curve becomes more smooth, and the abnormal points are greatly reduced, thus effectively improving the pickup accuracy.

Surface geological conditions are very complex in Block 71 of Yemen. The special seismic condition of this area has brought about technical difficulties in construction. In this paper, the author investigated the method of seismic data acquisition in Block 71 through analyzing geophysical conditions and tasks as well as data available and, exemplified by the project of 2D seismic data acquisition in 2006, demonstrated that the adoption of such measures as mixed sources, crooked and linear lines, observation system and excitation parameters could improve the data quality.

Based on soil radon gas survey in Quanzhou City and Jinjiang City, the authors conducted an investigation of the soil radon gas environment in an area of some 465 km2.  The results indicate that radon gas concentrations in soils of Quanzhou and Jinjiang urban areas are at a lower level, whereas those in soils of Quanzhou and Jinjiang suburbs are at a fairly high level. It seems that the radon gas concentration is mainly related to geological background: radon gas concentrations in soils derived from weathering of adamellite, moyite, and biotite schist are higher than those in soils derived from weathering of other rock types.

"Xiaoshan dried radish" is characterized by deliciousness, high yield, high anti-weather change capability and easy growing and processing. These fine qualities are related closely not only to the species but also to the soil geological and geochemical background of its producing area. Compared with soil average element values of Zhejiang plain, the producing area has higher MgO, B, P, CaO and Mn but lower N, K, Mo, Fe and Zn. Viewed from the effective state analytical results of soil nutrients and trace elements, the area contains abundant nitrogen of alkaline hydrolysis, Ge, Mn and Cu and an average amount of rapid available phosphorus, organic matter and Zn. As the soil maturity of the producing area is relatively low and the cropping index there is high, N and K in the soil tend to flow away, and B and Mo are deficient, which affects and restricts the yield and quality of the radish. It is suggested that trace element manure and organic manure should be added in time so as to maintain soil fertility in a scientific way.

Particle swarm optimization (PSO), based on the idea of a swarm of birds searching for foods, is a new global optimization scheme. It can find optimal regions in searching space through the interaction of individuals in a population of particles, with the advantages of efficient searching and easy implementation. This paper deals with the inversion of the magnetic data of tabular bodies by means of PSO in comparison with the genetic algorithm (GA). The inversion results of theoretical and practical data show that PSO can find the optimal solution with fairly high efficiency.

According to data collection requirements and characteristics of the newly developed magnetotelluric instruments, the authors developed a visualized data collection software using C++ program language. Through a friendly interface, users can easily control the whole collecting process, observe collecting signals, estimate the quality of signals and, by adopting some measures, ensure the quality of signals in the process of data collection.

This paper puts forward the triangle element method for calculating gravity anomaly of three-dimensional sphere-coronal model by using the divergence theorem. In this study, the volume integration was changed into surface integral, a series of triangles were used to fit the surface, and then the Green’s formula was adopted to change surface integral into line integral. At the same time, a reasonable calculation program was given. The surface gravity anomalies of homogeneous and non-homogeneous density sphere-coronal models were calculated and, as a result, the planar anomaly maps of the two models were drawn. An error analysis has proved the effectiveness and reliability of this method.

Center for Hydrogeology and Environmental Geology, CSG, Baoding  071051, China)
Abstract： The static effect of the AMT method is an unavoidable problem in groundwater survey in mountainous areas. Nevertheless, people have often paid too much attention to the special distribution of clay layers in Quaternary groundwater survey. Focused on the above two problems, the authors applied 2D finite cell numerical modeling to simulating the influence of the static effect on the TE, TM polarized apparent resistivity curves and the vertical resolution of conductive folia.

This paper deals with the advantages of the tilt derivative method in locating boundaries of magnetic and gravity sources and presents a new theory for explaining the inclination of the geological body, which is called non-absolute horizontal derivative of tilt derivative. Some models have been designed to prove the method, and the problems existent in the tilt derivative method are pointed out. The method was employed to explain the gravity potential data of a certain area, with good results obtained.

 Using the equations and principles of the velocity tomography technology, the authors studied the forward and inversion method for the geological model. The results show that such parameters of the model as its shape, location and slowness can be accurately obtained. First of all, the forward model was set up, the field was divided into regular rectangle grids, and the transmitting and receiving devices were installed respectively on the left and right edges of the section. Within the continuous transmission and reception, each velocity radial time can be obtained on the model. Then 20% noise was added to the travel time, the model was rebuilt with the mature ART method, and the inversion was employed to the model. It is shown that the inversion result approximates to the forward model, and the calculation precision and velocity are satisfactory.

During the geochemical survey performed in the Bacheli gold-molybdenum deposit of Heihe area, Heilongjiang Province, the Mapgis software was applied to drawing map that showed both sampling positions and primary geochemical data. Single element anomaly and comprehensive anomaly maps were completed by Surfer drawing software. The Mapgis software has such advantages as quick drawing, comprehensive attributes and advanced figure-synthesizing function. The comprehensive anomaly map of the study area drawn by Mapgis is coincident with that drawn by Surfer, which is helpful to detecting geochemical anomalies and guiding exploration. The integration of Mapgis with Surfer not only improves the velocity of data-processing but also reflects true metallogenic information. 

Hammer test is a common method for bolt nondestructive dynamic test, but the potential error reading from the wave pattern frequently occurs due to the inconsistent wave caused by the small impact area. The engineer dynamic detection is therefore of great significance in analyzing the hammer mechanic properties. In this paper, the impact between the hammer and the pole was simulated as a spring whose stiffness is K and whose mass is zero, so as to probe into the local deformation. Then the expression of the impact force and the pulse time during the impact were derived. The ANSYS/LS-DYNA software was used to simulate the stress wave pattern and the pulse width in the process, as the hammers had different masses and the radius of impact head and its elastic modulus had different impact velocities, and the prestressed bolt was excited by hammers with different masses and different hardnesses in laboratory. The results further describe the mechanics of the impact of the hammer and rock bolt and creates the condition for the improvement of the engineering detection quality in the rock bolt nondestructive dynamic detection.

Based on a comprehensive study of regional geological and seismic characteristics as well as the spatial variability of rock-mass, the authors applied such means as the excavation techniques and the support models (spatial layout, types, parameters, etc), Acoustic Emission (AE), Borehole-Television (BT), ultrasonic wave characteristics indicating rock-mass micro-fractures and damages to seek the mechanism of localized deformation and destabilization under the conditions of softened and shattered wall rocks. The practical prediction in the Yangchangwan coal mine shows that the accuracy of the prediction can meet the requirements of the construction standards. The rationality and feasibility of the related theory and the technical method are verified, and the wall rock stability and safe mining can be achieved. This study has provided scientific basis for engineering disaster prevention and alleviation.