This paper presents new data processing and interpretation methods for the high-precision magnetic data in search for deep-buried minerals in crisis mines. Such means as the three-dimensional visualized inversion based on the numerical integral of 3D bodies, the weak signal identification by the wavelet analysis tools, the equivalent dipole layer method for the fast reduction of magnetic data from an undulated relief to a horizontal plane, and the transformation of to, all fall into this category. The performance of these new methods was illustrated in search for deep-buried minerals in the Daye iron mine, and a magnetite ore body more than 30m thick was discovered by the drilling along No.15 exploration line arranged according to the authors' interpretation in 2005. The application of these new methods shows that the adoption of these new methods is essential in the continued resources exploration for crisis mines.

Located in North Qilian Mountains, Qinghai Province, Zhongnangou belongs to alpine meadow landscape. It has evident alpine-gorge incision and well-developed vegetation below slope, which are obviously unfavorable for granule mechanic motion. Studies indicate that transformation trends of the metallogenic elements in stream sediments of diverse granule grades are identical. The metallogenic elements decrease rapidly in quantity, and are concentrated in the fine size fraction, mainly in the form of sulfide facies. Researches also indicate that the conventional measuring methods for stream detrital sediments have the following defects: granule motion is restrained due to well-developed meadow; stream detrital sediments appear only in Grade 2~3 drainage, and hence much mineralization information might be lost at the reconnaissance stage; at the detailed investigation stage, it is very difficult to collect samples in the real stream sediments due to their limited distribution; where slope sediment samples are collected to replace stream sediment samples, the problem of non-unification of sampling media will occur.

The Yindongpo gold deposit is situated in an upper Palaeozoic carbon-silicon-mud formation. The pyrite typomorphic mineral shows a transitional attribute between the sedimentary origin and the hydrothermal origin. REE patterns assume gentle inclination towards the right without Eu anomalies. REE of ores and Liangwan granite have close relationship in sources. Sulphur isotope δ³⁴S is 3.1%, with high homogenization. Ores and wall rocks have similar lead isotope composition. They were derived from partial melting of South Qinling continent crust which subducted under North Qinling block. Compositions of radon and hydrogen isotopes indicate that ore-forming fluids came from joint evolution of meteoric, magmatic and metamorphic water. Mineralization has experienced three stages, namely, the formation of original sedimentary mineral source bed, the low-grade metamorphism and the preliminary enrichment of ore-forming elements, and the locating of ore-forming elements derived from mixed hydrothermal water.

This paper has discussed geochemical characteristics of different genetic types of ferruginous strata on the basis of achievements made in regional geochemical rock survey. In strata of important sedimentary iron deposits, the quality fractions of Al₂O₃, Ti, P, V, Cr, Ni, Cu, Zn and the w(Fe₂O₃)/w(FeO), w(Sr)/w(Ba) and w(La)/w(Y)ratios are relatively high,whereas the quality fractions of Rb, L, Cs, Sc and w(K₂O)/w(Na₂O)ratios are relatively low. The strata of marine sedimentary iron deposits are strongly enriched in Sb, Li, B, Hg, Sr and K₂O,but depleted in FeO,Na₂O, CaO, Mn, Ti, P, V, Cr, Zr, Ba. Besides, the quality fraction of REE and the w(Fe₂O₃)/w(FeO)ratios are rather low. These geochemical characteristics reflect a special geological-tectonic environment.

With a certain depression of Bohai bay basin as an example, this paper deals with the application effect of such new techniques as the second-vertical derivative after downward continuation to a given depth, the 3D apparent density inversion, and the joint modeling and inversion with gravity, magnetic and seismic data in LCT platform. The anomaly of second-vertical derivative after downward continuation to a certain depth can reflect small-scale, low amplitude and deep-seated buried hills more effectively and intuitively compared with the conventional second-vertical derivative anomaly. The 3D apparent density inversion section can reflect the density variation of the geological body both vertically and horizontally and provide evidence for buried hill research. The application of LCT joint inversion with gravity, magnetic and seismic data can quantitatively determine the depth and amplitude of buried hills.

two-dimensional flexure hinge gradiometer was developed in combination with a two-dimensional capacitance transducer. This design effectively improves the sensitivity and stability of the torque-style gradiometer. Preliminary experimental results show that the resolutions of the gradients W_xx-W_zz and W_xz come to 47 E and 37 E, respectively, restricted mainly by electrical noise.

Aimed at tackling the stochastic variations caused by non-artificial natural factors and accidental factors such as nonpoint source contamination and point source contamination in geochemical maps for different continental and sea media of eastern Zhejiang coastal area, this paper puts forward a geochemical map formation method for different continental and sea media based on a suitable data-processing model and color area spatial distribution so as to improve the map face effects.

The analytical method for mobile forms of gold has been improved by the authors and a new analytical method is put forward in this paper.The method was used to analyze mobile forms of gold in a large number of samples.An application case in a gold deposit within a cold forest landscape area in Northeast China is cited.The results show that adsorbed and exchangeable,organically bound and occluded forms of gold in Fe-Mn oxides can show evident anomalies over the ore bodies,with the anomalies of organically bound gold being the strongest.Organically bound gold is the most effective mobile form in search for buried gold deposits in this kind of landscape areas.The relative error of analytical duplicates is less than 50%,which can meet the analytical requirement for mobile forms of gold.

Inverter, the weakest part of a high frequency and high power transmitter for electrical exploration, is liable to be destroyed. The reason is that the performance of the inverter is not good enough and the inverter protection is not satisfactory. Aiming at solving these problems, this paper presents a new inverter system which bases itself on a new power module-IPM and adopts right driver circuit and buffer circuit. It fits different transmitting frequencies and polar distances with proper settings of dead time, which is adjustable under the control of a micro controller.

The IMPULSE helicopter frequency electromagnetic system imported from Canada is a new type digital and broad band system. This paper has analyzed the exploration efficiency of the IMPULSE system in the Hongguang iron deposit, including profile and plan characteristics of the electromagnetic and magnetic field, the transformed apparent resistivity and the apparent resistivity depth section. The surveying result between the IMPULSE system and the Tridem fixed plane EM system was also compared. It is shown that the IMPULSE system has higher penetration and resolving power than the Tradem system, and that the IMPULSE system will surely show good exploration efficiency in further mineral and groundwater exploration in China.

The ground penetrating radar (GPR) system usually uses ultra-broadband short pulse, so the antenna must have a wideband. The bowtie antenna with linear discrete resistor loadings was analyzed in this paper by using the method of moments. The result shows that, with such a loading form, the antenna can get a wideband and the radiated short pulse can have a flat tail. The antenna can therefore be applied to the GPR system.

A mass of model experiments are performed. By studying the response of several typical conductive bodies in dipole transient electromagnetic systems, this paper analyses the exploration resolving power of dipole configuration, discusses the problems about dipolar distance and the way to fix the detecting point, and finally concludes the working characteristics of this configuration. The forms of response curves of these bodies in dipole transient electromagnetic measurement are complicated and more arduous to interpret. However, the disturbing of primary field is small for dipole configuration and it has strong ability to distinguish dissimilar bodies from background. Moreover, it is very convenient and flexible. So it adapts to be used in the transient electromagnetic detecting of shallow seafloor and other special environment.

Till now, time-lapse seismic monitoring of continental thin-interbedding reservoir has not made a remarkable breakthrough, and hence the strengthening of the study and application of the time-lapse seismic method as well as the cross-equalization processing technique is of great significance. As a most effective method for improving the repeatability of time-lapse seismic data, the cross-equalization processing technique has been widely used with excellent results achieved. Through the cross-equalization processing of time-lapse seismic monitoring data obtained in the development of continental heavy oil thin-interbedding reservoir with the use of thermal recovery, it is shown that the cross-equalization processing is helpful to recognizing time-lapse seismic anomaly and determining the position of thermal front. Nevertheless, when the repeatability of original seismic data is very bad, such a processing can only improve the repeatability of time-lapse seismic data, but with no good seismic anomaly detected. The key to the successful performance of time-lapse seismic monitoring for the continental thin-interbedding reservoir is the enhancement of the repeatability of seismic wavelets and seismic data. The amplitude attribute seems to be one of the major criteria for the thinner reservoir.

Due to the specific surface conditions as well as the complex and varied surface structure of the beach and shallow sea area, the exploration work in such an area is different from both continental exploration and sea exploration. In the amphibian zone, in particular, there exist two working means (sea and continental means). Based on a systematic study of such field collection links in the field as the excitation seismic source, the detector and the observational system, the authors put forward the method for solving the difficult problem of collecting high-quality seismic data. On the basis of a thorough investigation into the interference wave suppression and the difference correction, a complete set of high-precision and practical special techniques for oil and gas exploration in the beach and shallow sea area was developed, and the results show that its geological effect is satisfactory.

The high-resolution position data in the centimeter grade are extracted from the binary output records of the hand-held GPS position indicator, and the multiple average measurement and post-operation position difference correction method are used so as to decrease the planar locating error of the portable and cheap hand-held GPS position indicator from several meters to 1 m or so. Thus the precision of the sub-meter grade can be attained.

The variance cube technique is based on the statistic principle. The correlation of the seismic signals between the neighboring channels in the 3D seismic data body is used to calculate the variances of the sample spots and extract the discontinuous information in the data body, with the purpose of recognizing such lithologic variation spots as small faults and collapse pillars. Exemplified by a mining area in a coalfield of Shanxi Province and based on testing various parameters of the variance cube, this paper deals with the effects of such factors as the operation mode of the variance cube, the channel number of the operation and the size of the time window upon the calculation results. With the achievements made by the authors, the variance cube technique can yield relatively fine results in detecting such geological bodies as coal seam small faults and collapse pillars.

Two arguments have been advanced in this paper by spreading the "theorem of interchange between magnetization direction and magnetic field component direction" to non-uniform magnetization. The component in any direction of the total field intensity figured out from the single horizon is called component of single-layer field intensity. The even horizon in a broad sense is just the component of single layer field intensity.

The relationship between the dispersion curve of Rayleigh wave and the structure of multilayered media is nonlinear, so the inversion method of the dispersion curve should be nonlinear. In this paper the authors applied the Quasi-Newton method to the inversion of the fundamental mode, with good effects obtained. With a practical example, the method was verified.

Mercury pollution in a certain large city of Guangdong Province is spatially related to dense population and crowded factories. In the longitudinal direction of the soil, the pollution is heavy at the surface and becomes lower downward. The different phases of mercury are also somewhat related to environmental materials (organic matter, grain sizes of soil and pH values). The high mercury contents lead to the high mercury concentration in the atmosphere.

This paper describes a typical example illustrating the application of fuzzy evaluation method and computer technology to the field of environmental quality evaluation,i.e.,the Environmental Data Analytical System for Ministry of Agriculture,with the emphasis placed on the procedures of fuzzy evaluation and the realization of fuzzy evaluation in the Environmental Data Analytical System.The functions,structure,and innovation of that system are also discussed in this paper.

This paper deals with the principle and method of ground penetrating radar (GPR). With practical engineering examples, the author describes the application of ground penetrating radar to the nondestructive concrete construction quality inspection. As a nondestructive inspection method, GPR is widely used in many fields and the result of the application is satisfactory.