一.Safety Problems Faced By Coal Mines

     1.1 Status Quo

      My country is a big coal-producing country. At present, coal accounts for about 70% of my country's primary energy consumption. For a long time to come, coal will still be a very important strategic resource and play an extremely important role in my country's economic and social development. In 2007, my country's total coal output was 2.523 billion tons, which increased to 2.716 billion tons in 2008, an increase of 7.65%. However, the total number of deaths in my country's coal mines is three times that of other coal-producing countries in the world, and the safety production situation in coal mines is still very severe. In my country's primary energy production and consumption structure, coal has always accounted for about 70% of the total, especially in the in the 1950s and 1960s, coal consumption even accounted for 80% to 90% of total energy consumption. Characteristics of my country's coal industry: 95% of coal mining is underground operations. In underground coal mining, there are five natural disasters: water, fire, gas, coal dust and roof. In the production process, mining, excavation, machinery, transportation, improper management of processes and links will lead to accidents, seriously endangering the lives of employees. The continuous coal safety accidents endanger the life of every miner, bring heavy disasters to the families of the miners, increase the production cost of enterprises, and affect the construction of a harmonious society. The frequent occurrence of mining accidents is extremely inconsistent with the political background of building a socialist harmonious society in our country, is inconsistent with the people-oriented scientific development concept, and completely deviates from the party's governing goals. The problem is imminent, otherwise there may be a risk of piling up. Formulate perfect coal mine safety production laws and regulations, and establish a relatively complete coal mine safety management organization. The state has continuously strengthened supervision and rectification of coal mine safety production, but major accidents still occur frequently. Coal mine safety is a top priority that is related to the physical and mental health and life safety of coal mine workers, as well as to the national economy.

 

     1.2 Classification of Security Issues

• permeable

               Coal mine water penetration refers to the accident caused by digging through the tunnel wall to connect to the groundwater or the abandoned tunnel when the coal mine is being mined in the tunnel.

• coal mine collapse

 Coal mine subsidence should be divided into gob subsidence and karst subsidence.
Goaf subsidence：Long-term large-scale mining forms a goaf. As the area of ​​the goaf continues to increase, the roof (overlying rock) of the coal seam loses its support, and the roof rock layer bends, breaks, and collapses, resulting in Tilt deformation and horizontal movement. During the caving process, the rock mass around the goaf is deformed, loosened, and even damaged, so that the overlying rock layer in the goaf bends and sinks.
Such collapses can be prevented by surveying mining activity and signs on the ground.
Karst collapse：Karst collapse (karst breakdown survey) refers to the karst cave in the lower karst rock layer or the soil cave in the overlying soil layer in the karst area. A general term for slump or subsidence. In the mining area, the surrounding groundwater level is usually changed due to the drainage of groundwater in the karst area.

• Gas

          Also known as coal seam gas (gas of coalseam), coal seam methane. A mixture of methane, carbon dioxide and nitrogen escaping from coal and surrounding rock. Gas is a harmful factor in coal mine production. It not only pollutes the air, but also when the gas content in the air is 5% to 16%, it will cause an explosion in case of fire and cause an accident.

二.Solution

     2.1 Overall function

     Coal mines are flooded, generate gas, and in front of landslides, most of the time there will be some omen. When an accident occurs, taking precautions in advance can reduce or completely avoid the accident. Aiming at the complex mining environment of coal mines, our company has developed a coal mine early warning system with early warning by using sensors and wireless technology.

     This system is composed of front-end sensors, wireless transmission, management platform, and alarm devices. Its block diagram is as follows:

      

     2.2 Detailed function front sensor

• Front Sensor

                 Gas Alarm

                       When the methane, carbon monoxide and carbon dioxide in the air increase, the alarm will upload these types of air values ​​to the platform for alarm.

                 Water Penetration Alarm

                       When a serious water infiltration event occurs in a coal mine, the initial water seepage is slight. During the water seepage stage, an alarm is received through a water immersion rope and transmitted to the management platform. The management platform can read the data of the water level sensor to know the water depth.

                 Landslide Alarm

                        Before the coal mine collapses, there will be some deformation, when the coal mine has deformation, the displacement and deformation sensors will upload the deformation data to the platform.

• Transmission Part

          The complex terrain of coal mines brings great challenges to sensor data transmission. In this system, a variety of communication technologies are fully integrated to collect the data in the coal mine. The following is a brief description of the transmission technology we use:

            The biggest feature of LORA wireless transmission is that it can travel farther than other wireless methods under the same power consumption conditions, realizing the unity of low power consumption and long distance. Expand 3-5 times.

              GPRS/3G/4G transfer When the sensor data is transferred from the mine, use the operator's base station to transfer the data to the cloud through GPRS/3G/4G.

• Alarm Section

                  Sound and light alarms are installed in every security guard and management office. When there is data exceeding the standard, the sound and light alarm will turn on the alarm.

              LED Display In the security room, the leader's office is equipped with an eye-catching LED display, and the LED display plays the real-time sensor data of the downhole.。

三．Product Parameter Function

     3.1 Platform

       The platform is managed by cloud platform and adopts advanced B/S architecture. It can collect the value of the front-end sensor in real time, and manage the data of the front-end sensor at the same time. The platform can be customized according to user requirements.

     3.2 Transmission Products

           3.2.1 Wireless Gateway

• 4G Wireless Transfer Gateway (HY-DTU-001)

           This product integrates GPRS/3G/4G remote program wireless transfer module, integrates LORA/SUB 1GHZ non-transfer module for local, and integrates CAN, RS485 communication bus. It can collect local sensor data to the gateway by LOAR, RS485, CAN, etc., and then upload the data to the cloud or management platform through GPRS/3G/4G/Ethernet. The following are the photos and parameters of this device:

                

 

Project	Subproject	Parameter
Master	Master	Industrial grade CPU, main frequency 540MHZ
	Memory	64M Byte
	FLASH	32M Byte
Wireless	Wifi Standard	2.4GHZ，Support IEEE802.11b/g/n
	LORA	430MHZ~510MHZ,868MHZ~915MZ Optional
	Sub 1G Wireless	430MHZ~510MHZ,868MHZ~915MZ Optional
	2G/3G/4G	FDD LTE,TDD LTE,DC-HSPA+/HSPA+/HSPA/WCDMA,TD-SCDMA/GSM/GPRS/EDGE
对外接口	Network Interface	1 Ethernet interface, 1 WIFI, 1 2G/3G/4G module
	Supply Voltage	DC 6V~36V input
	Working Environment	Working temperature -30℃~75℃, humidity 0%~90%RH without condensation
	Working Current	Power on: <12V/200mA, maximum current <12V/400mA
	Other Interface	Two RS485 interfaces, two I/O interfaces, can be used as one 24Bit AD input

 

• 4G multifunctional wireless transfer gateway (HY-DTU-002)

           On the basis of HY-DTU-001, this gateway adds support for I/O sensors, and can control devices through I/O externally. Below are the pictures and parameters of this device

 

Project	Subproject	Parameter
Master	Master	Industrial grade CPU, main frequency 540MHZ
	Memory	64M Byte
	FLASH	32M Byte
Wireless	Wifi Standard	2.4GHZ, support IEEE802.11b/g/n
	LORA	430MHZ~510MHZ, 868MHZ~915MZ optional
	Sub 1G Wireless	430MHZ~510MHZ, 868MHZ~915MZ optional
	2G/3G/4G	FDD LTE,TDD LTE,DC-HSPA+/HSPA+/HSPA/WCDMA,TD-SCDMA/GSM/GPRS/EDGE
External Interface	Network Interface	1 Ethernet interface, 1 WIFI, 1 2G/3G/4G module
	Supply Voltage	DC 6V~36V input
	Working Environment	Working temperature -30℃~75℃, humidity 0%~90%RH without condensation
	Working Current	Power on: <12V/200mA, maximum current <12V/400mA
	Other Interface	Two RS485 ports, 20 I/O ports, five 24 Bit ADC inputs

 

      3.2.2 Wireless Data Acquisition Node (HY-TNOD-001)

• LORA wireless protocol conversion equipment

              This device is responsible for collecting the sensor data of RS485, I/O interface type, and uploading the sensor data to the gateway through LORA. Its main function is to turn a traditional sensor into an IoT device without modifying the structure of the sensor, as long as the following devices are used. The pictures and parameters of this device are as follows:

Project	Subproject	Parameter
Master	Master	Industrial grade cpu, main frequency 72mhz
	Memory	128 KByte
	FLASH	32 KByte
	LORA	430mhz~510mhz, 868mhz~915mz optional
	Sub 1G Wireless	430mhz~510mhz, 868mhz~915mz optional
	Supply Voltage	DC 6v~36v input
	Working Environment	Working temperature -30℃~75℃, humidity 0%~90%rh without condensation
	Working Current	Power on: <12v/200ma, maximum current <12v/400ma
	Other Interface	Two rs485 interfaces, 4 i/o interfaces

 

      3.3 Sensor Products

        3.3.1 Gas alarm

• VOCS (ES72C-VOCS)

                  VOCs have a huge impact on human health, are toxic, irritating, and cause cancer. It is the key precursor for the formation of PM2.5 and ozone, and is an important cause of compound air pollution. ES72C-VOCS, a VOCs collector, uses imported high-end sensors to combine with our wireless gateway to become a high-precision online VOCs data collector. The following are the pictures and parameters of the product:

 

Project	Subproject	Parameter
Master	Master	Industrial Grade Cpu, Main Frequency 540mhz
	Memory	64M Byte
	FLASH	32M Byte
Wireless	Wifi Standard	2.4ghz, Support Ieee802.11b/g/n
	LORA	430mhz~510mhz, 868mhz~915mz Optional
	Sub 1G Wireless	430mhz~510mhz, 868mhz~915mz Optional
	2G/3G/4G	FDD LTE,TDD LTE,DC-HSPA+/HSPA+/HSPA/WCDMA,TD-SCDMA/GSM/GPRS/EDGE
External Interface	Network Interface	1 Ethernet Interface, 1 2g/3g/4g Module
	Supply Voltage	Dc 6v~36v Input
	Working Environment	Working Temperature -30℃~75℃, Humidity 0%~90%rh Without Condensation
	Working Current	Power On: <12v/200ma, Maximum Current <12v/400ma
	Other Interface	Two Rs485 Ports, 20 I/o Ports, Five 24 Bit Adc Inputs
Sensor Parameters	Process Gas	High Temperature, High Humidity Flue Gas Or Other Measured Gas
	Constant Temperature	The Temperature After Gas Treatment At 25°c Can Be Set
	Sampling Flow	4L/min
	Sampling Humidity	0~99%RH
	Sampling Temperature	-40℃~+200℃
	System Heating	Optional Function To Prevent The Pipeline From Freezing In Extremely Cold Areas

 

• Multi-parameter gas detector (EC-AIRANSO2-001)

 

    

                  The four-gas temperature and humidity integrated detector adopts the original imported sensor and a new 32-bit low-power processor; the instrument is beautiful and elegant, and the four detection gases can be selected arbitrarily; the circuit adopts 4-layer wiring, which is stronger for weak signals and anti-interference; Independent high-precision imported 16-bit AD chip and unique signal processing algorithm, the measurement data accuracy is higher and more stable; RJ45, RS48 multiple output signals can be selected, and it is convenient to connect to various alarm controllers, PLC, DCS and other control systems; products Widely used in urban tunnels, integrated pipe gallery, metallurgy, petroleum and petrochemical, municipal, chemical and other industries.

Project	Parameter
LORA	430mhz~510mhz, 868mhz~915mz Optional
Sub 1G Wireless	430mhz~510mhz, 868mhz~915mz Optional
2G/3G/4G	Support Fdd Lte,tdd Lte,dc-hspa+/hspa+/hspa/wcdma,td-scdma/gsm/gprs/edge
Precision	±3%FS
Preheat Time	≤8 Seconds
Output Signal	1 Channel 4~20ma Telecommunication Signal Output/rs485
System Language	Chinese And English Can Be Switched
Test Content	Methane, Carbon Monoxide, Oxygen, Hydrogen Sulfide, Carbon Monoxide, Temperature And Humidity
Protection Class	IP65
Scope Of Test	Methane: 0-100% LEL Oxygen: 0-30%VOL Carbon monoxide: 0-500ppm Hydrogen sulfide: 0-100ppm Thermometer: -40-80℃ Humidity: 0-100%RH
Power Supply	DC 24V
Operating Temperature	-40℃~70℃
Installation Method	wall-mountedpipeintegrated
Operating Voltage	24VDC

• Combustible gas alarm (EC-AIRVOC-003)

               It is used to detect whether the combustible gas exceeds the standard, and to detect the concentration of various combustible gases.

Project	Parameter
LORA	430mhz~510mhz, 868mhz~915mz optional
Sub 1G Wireless	430mhz~510mhz, 868mhz~915mz optional
2G/3G/4G	FDD LTE,TDD LTE,DC-HSPA+/HSPA+/HSPA/WCDMA,TD-SCDMA/GSM/GPRS/EDGE
Installation Method	wall-mounted, natural circulation, pump-suction circulation
Temperature Range	-40℃~70℃
Humidity Range	10~95%RH
Explosion-proof Grade	EXD II CT6 GB
Protection Class	IP65
Power Supply	dc 24v

 

四．Product Quotation

     4,1 Platform Quotation

       This part should be quoted according to the customer's requirements, and each customer's needs are different.

     4.2 Transmitting part of the quotation

name	Market Retail Price	Ex-factory Price
4G wireless transmission gateway (HY-DTU-001)	9980
4G wireless transmission gateway (HY-DTU-002)）	13800
Wireless Data Acquisition Node (HY-TNOD-001)	1800

 

     4.3 Sensor Part Quotation

 

Name	Market retail price	Ex-factory price
VOCS (ES72C-VOCS)	35000
EC-AIRANSO2-001	18000
EC-AIRVOC-003	10000

 

    4.4 Alarm part quotation

Name	Market retail price	Ex-factory price
Audible Alarm	300
LED Display	(It depends on the customer's requirements here, non-standard products)