Characteristics of coal resources in China and statistical analysis and preventive measures for coal mine accidents

In the process of green and smart mine construction under the context of carbon neutrality,China's coal safety situation has been continuously improved in recent years.In order to recognize the development of coal production in China and prepare for future monitoring and prevention of safety incidents,this study mainly elaborated on the basic situation of coal resources and national mining accidents over the past five years(2017-2021),from four dimensions(accident level,type,region,and time),and then proposed the preventive measures based on accident statistical laws.The results show that the storage of coal resources has obvious geographic characteristics,mainly concentrated in the Midwest,with coal resources in Shanxi and Shaanxi accounting for about 49.4%.The proportion of coal consumption has dropped from 70.2%to 56%between 2011 and 2021,but still accounts for more than half of the all.Meanwhile,the accident-prone areas are positively correlated with the amount of coal production.Among different levels of coal mine accidents,general accidents had the highest number of accidents and deaths,with 692 accidents and 783 deaths,accounting for 87.6%and 54.64%respectively.The frequency of roof,gas,and transportation accidents is relatively high,and the number of single fatalities caused by gas accidents is the largest,about 4.18.In terms of geographical distribution of accidents,the safety situation in Shanxi Province is the most severe.From the time distribution of coal mine accidents,the accidents mainly occurred in July and August,and rarely occurred in February and December.Finally,the"4+4"safety management model is proposed,combining the statistical results with coal production in China.Based on the existing health and safety management systems,the manage-ments are divided into four sub-categories,and more specific measures are suggested.

Analysis of Lymph Node Metastases of 1,526 Cases with Thoracic Esophageal and Cardiac Carcinomas: A Random Sampling Report froni the Fourth Hospital of Hebei Medical University from 1996 to 2004

OBJECTIVE To summarize the regular pattern and state oflymph node metastasis of patients with esophageal and cardiaccarcinomas,so as to analyze factors influencing lymph nodemetastasis.METHODS Clinical data collected from 1,526 thoracicesophageal and cardiac carcinoma patients who were admitted inthe Fourth Hospital of Hebei Medical University during a periodfrom January 1996 to December 2004,were randomly selectedand an Access Database of the patient's information was set up.Eight clinico-pathologic factors,including the patient's age,tumorlocation and size,pathological classification,the depth of tumorinvasion,vascular tumor embolus (VTE),the state of surroundingorgan encroachment and the status of tumor residues,wereidentified.A correlation between these factors and metastases wasstatistically analyzed using SPSS13.0 software.RESULTS Lymph node metastatic sites from esophagealcarcinomas included the thoracic and abdominal cavity.Lymphnode metastasis from the superior esophageal carcinomasmainly occurred in the neck and thoracic cavity.There was atwo-way lymph node metastasis in the patients with the middleesophageal carcinoma.The inferior esophageal carcinomas mainlymetastasized to the paraesophageal,paragastric cardia,and leftgastric artery lymph nodes.The rate and degree of the metastasisfrom the inferior esophageal carcinomas were significantly highercompared to those of the superior and the middle esophagealcarcinomas (P<0.0125).The degree of abdominal lymph node metastasis fromcarcinomas of the gastric cardia was significantly higher comparedwith that of esophageal carcinomas.In the group with carcinomaof the gastric cardia,the rate and degree of the lymph nodemetastases in the paragastric cardia and left gastric artery weresignificantly higher compared to the group with esophagealcarcinoma (P<0.05).Paraesophageal lymph node metastasis fromcarcinomas of the gastric cardia in the thoracic cavity frequentlyoccurred,too,and the degree of the metastasis was similar to thatof esophageal carcinoma.There was no significant difference inthe rate and degree of the paraesophageal lymph-node metastasisbetween the group with carcinoma of the gastric cardia comparedto those with esophageal carcinoma (P>0.05).Multifactoriallogistic regression analysis showed that the tumor size,depth oftumor encroachment,VTE,and tumor residues could all bringabout obvious impact on lymph-node metastases (P<0.05).CONCLUSION Lymph node metastasis from superioresophageal carcinomas mainly occurs in the neck and thoraciccavity.The middle esophageal carcinomas presented a two-waylymph-node metastasis (both the upwards and the downwards),and the lymph node metastasis from inferior esophagealcarcinomas mainly occurred in the thoracic and abdominal cavities.The metastases of carcinoma of the gastriccardia were most commonly found in the abdominalcavity,with frequent paraesophageal lymph-nodemetastasis.The sufficient attention should be paidto neck lymph node clearance in cases of esophagealcarcinoma.What is of the greatest concern is theclearance of the left gastric artery lymph nodes,andalso in cases of gastric cardia carcinoma,clearance,the paraesophageal lymph nodes.With an increasein the tumor size and depth of tumor encroachment,and occurrence of VTE and tumor residual cells,therisk of lymph node metastasis is significantly raised (P<0.05).

Analysis of Prognostic Factors of Esophageal and Gastric Cardiac Carcinoma Patients after Radical Surgery Using Cox Proportional Hazard Model-A Random Sampling Study from the Fourth Hospital of Hebei Medical University during the Period of 1996-2004

OBJECTIVE To retrospectively analyze clinical data of patientsfrom our hospital who underwent radical surgery for esophagealcarcinoma and for adenocarcinoma of the gastric cardia,as well asto investigate prognostic factors affecting the long-term survival ofthe patients.METHODS Data from the patients eligible for our study,admitted to the 4th Hospital of Hebei Medical University fromJanuary 1996 to December 2004,were randomized,and 12distinctive clinicopathologic factors influencing the survival rateof those who underwent radical surgery for esophageal carcinomaor carcinoma of the gastric cardia were collected.Univariate andmultivariate analysis of these individual variables were performedusing the Cox proportional hazard model.RESULTS It was shown by univariate analysis that age,tumorsize,pathologic type,lymph node status,TNM staging,depthof infiltration and encroachment into local organs,etc.,were thefactors that markedly influenced the prognosis of patients(P<0.01).Multivariate analysis showed that pathologic type,numberof the lymph node metastases,involvement of local organs,andTNM staging were independent prognostic factors(P<0.05).CONCLUSION The independent factors influencing theprognosis of patients with esophageal cancer and carcinoma ofthe gastric cardia include pathologic type,number of lymph nodemetastases,involvement of local organs and TNM staging.Themain prognostic factors affecting the patient's survival are patientage,tumor size and depth of infiltration.In addition,patients withinvolvement of the local organs have a worse prognosis,and theyshould be closely followed up.

Analysis of Clinicopathologic Features of Esophageal Carcinoma Patients Undergoing Surgery-a Report of 4,329 Cases

OBJECTIVE To investigate the clinicopathological features of esophageal carcinoma （EC） patients, and to analyze epidemiologic characteristics and the current situation of esophageal cancioma in the southern area of Hebei Province. METHODS A total of 4329 patients with esophageal cancinoma, undergoing surgery in the Fourth Hospital of Hebei Medical University during a period from January 1996 to December 2005, were selected. Collection and statistical analysis of the pathologic data were performed using a SAS 6.0 software package. RESULTS Over the past ten years, there has been a tendency for an increase in the mean age of EC onset （P 〈 0.05）, a downtrend in the percentage of squamous cancer （SqCa） （P 〈 0.05） and an uptrend in the frequency of small cell carcinoma （P 〈 0.05）. In clinical stages, there was a drop in the percentage of Stage-Ⅱ squamous EC patients （P 〈 0.05）, and an increase in that of Stage-Ⅳ patients （P 〈 0.05）. There were statistical differences in sex, age, pathologic types, depth of infiltration, ratio of stages and lymph node metastasis, etc. among the superior, middle and inferior segments of the EC diseased region （P 〈 0.05）. CONCLUSION It was relatively late for the EC patients from this area to see a doctor, resulting in a drop in the ratio of SqCa and an ascensus in that of small cell cancer. However, due to a low incidence of adenocarcinoma, no obvious ascending tendency was found in the frequency of this carcinoma over the past ten years.